Time-dependent proregenerative effects of exogenous melatonin on the transected sciatic nerve / Efectos proregenerativos dependientes del tiempo de la melatonina exógena en el nervio ciático seccionado

SUMMARY: Microsurgical procedures are the treatment of choice of peripheral nerve injuries, but often fail to reach full functional recovery. Melatonin has neuroprotective actions and might be used as a possible proregenerative pharmacological support. Therefore, the aim of this study was to analyze the time-dependence of the neuroprotective effect of melatonin on the overall fascicular structures of both ends of the transected nerve. Sciatic nerve transection was performed in 34 adult male Wistar rats divided in four groups: two vehicle groups (N=7) treated intraperitoneally for 7 (V7) or 21 (V21) consecutive days with vehicle (5 % ethanol in Ringer solution) and two melatonin groups (N=10) administered intraperitoneally 30 mg/kg of melatonin for 7 (M7) or 21 (M21) consecutive days. At the end of the experiment, proximal stump neuroma and distal stump fibroma were excised and processed for qualitative and quantitative histological analysis. Intrafascicular neural structures were better preserved and the collagen deposition was reduced in the melatonin treated groups than in the vehicle groups. Myelin sheath regeneration observed through its thickness measurement was statistically significantly (p<0,05) more pronounced in the M21 (1,23±0,18 µm) vs. V21 group (0,98±0,13 µm). The mean volume density of the endoneurium was lower in both melatonin treated groups in comparison to the matching vehicle treated groups. Although not statistically different, the endoneural tube diameter was larger in both melatonin groups vs. vehicle groups, and the effect of melatonin was more pronounced after 21 days (24,97 % increase) vs. 7 days of melatonin treatment (18,8 % increase). Melatonin exerts a time-dependent proregenerative effect on nerve fibers in the proximal stump and an anti-scarring effect in both stumps.

Los procedimientos microquirúrgicos son el tratamiento de elección de las lesiones de los nervios periféricos, pero a menudo no logran una recuperación funcional completa. La melatonina tiene acciones neuroprotectoras y podría ser utilizada como un posible apoyo farmacológico proregenerativo. Por lo tanto, el objetivo de este estudio fue analizar la dependencia del tiempo del efecto neuroprotector de la melatonina sobre las estructuras fasciculares generales de ambos extremos del nervio seccionado. La sección del nervio ciático se realizó en 34 ratas Wistar macho adultas divididas en cuatro grupos: dos grupos de vehículo (N=7) tratados por vía intraperitoneal durante 7 (V7) o 21 (V21) días consecutivos con vehículo (5 % de etanol en solución Ringer) y dos grupos grupos de melatonina (N=10) a los que se les administró por vía intraperitoneal 30 mg/kg de melatonina durante 7 (M7) o 21 (M21) días consecutivos. Al final del experimento, se extirparon y procesaron el neuroma del muñón proximal y el fibroma del muñón distal del nervio para un análisis histológico cualitativo y cuantitativo. Las estructuras neurales intrafasciculares se conservaron mejor y el depósito de colágeno se redujo en los grupos tratados con melatonina respecto a los grupos con vehículo. La regeneración de la vaina de mielina observada a través de la medición de su espesor fue estadísticamente significativa (p<0,05) más pronunciada en el grupo M21 (1,23±0,18 µm) vs V21 (0,98±0,13 µm). La densidad de volumen media del endoneuro fue menor en ambos grupos tratados con melatonina en comparación con los grupos tratados con vehículo equivalente. Aunque no fue estadísticamente diferente, el diámetro del tubo endoneural fue mayor en ambos grupos de melatonina frente a los grupos de vehículo, y el efecto de la melatonina fue más pronunciado después de 21 días (aumento del 24,97 %) frente a los 7 días de tratamiento con melatonina (18,8 % de aumento). La melatonina ejerce un efecto proregenerativo dependiente del tiempo sobre las fibras nerviosas del muñón proximal y un efecto anticicatricial en ambos muñones.

Progress of the central nervous system myelin sheath development and related diseases in children / 国际儿科学杂志

The myelin sheath of the central nervous system(CNS)is a multilayer lipid membrane with oligodendrocyte membrane surrounding the axon.The development of myelin sheath in children follows the corresponding laws of time and space, and this process of myelination is considered to be related to children′s proper behavior and function.The myelin sheath development of CNS in childhood is a multi-step and extremely complex process, and the integrity of myelin sheath plays a crucial role in shaping CNS function.At present, it has been found that many neurological diseases in children, such as multiple sclerosis, transverse myelitis and pediatric optic neuritis are closely related to myelin sheath abnormality.Therefore, this paper reviews the progress of myelin sheath development and related diseases in childhood, so as to provide a basis for clinical diagnosis and treatment of myelin sheath abnormalities.

Effect of Modified Shuyuwan on Hippocampal Myelin Sheath Injury in Vascular Dementia Rats Through Cx43/Glu/AMPAR Pathway / 中国实验方剂学杂志

ObjectiveTo investigate the effect and mechanism of modified Shuyuwan （SYW） on hippocampal myelin sheath injury in vascular dementia （VD） model rats. MethodSixty male SD rats of SPF grade were randomly divided into sham operation group， model group， and high-， medium- and low-dose modified SYW groups， with 12 rats in each group. The VD model was induced by bilateral carotid artery ligation in rats of the groups except for those of the sham operation group. After modeling， rats were screened by the water maze test， followed by drug treatment by gavage. Specifically， rats in the modified SYW groups were treated with modified SYW at 10， 5， 2.5 g·kg-1·d-1， accordingly， and those in other groups were administered with the same amount of normal saline. After intragastric administration for 28 days， the spatial learning and memory abilities of rats were detected by the water maze test. The hippocampal neuron structure was observed by hematoxylin-eosin （HE） staining. The content of hippocampal tumor necrosis factor （TNF）-α， interleukin-6 （IL-6）， and glutamate （Glu） was observed by biochemical detection. The hippocampal expression of myelin basic protein （MBP）， astrocyte activation marker glial fibrillary acidic protein （GFAP）， and connexin 43 （Cx43） was detected by immunofluorescence detection. The myelin sheath structure in the hippocampus was observed by the electron microscope. The α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid receptor （AMPAR） and Cx43 protein expression was detected by Western blot. ResultCompared with the sham operation group， the model group showed prolonged escape latency （P<0.01）， decreased times of crossing the original platform and percentage of target quadrant detention time （P<0.01）， disordered neuron structure in the hippocampal CA1 region， loose myelin sheath lamella with blurry edge， up-regulated expression levels of TNF-α， IL-6， and Glu in the hippocampal CA1 region， especially Glu （P<0.01）， reduced expression of AMPAR （P<0.01）， increased protein expression of p-AMPAR and Cx43 （P<0.01）， significantly dwindled protein expression of MBP in the myelin sheath， and enhanced fluorescence co-labeled by GFAP and Cx43. Compared with the model group， the modified SYW groups showed shortened escape latency （P<0.05）， increased times of crossing the original platform and percentage of target quadrant detention time （P<0.05）， closely arranged hippocampal neuron structure， denser myelin sheath lamella with clear edge， down-regulated expression levels of TNF-α， IL-6， and Glu in the hippocampal CA1 region， especially Glu （P<0.01）， up-regulated AMPAR （P<0.01）， reduced protein expression of p-AMPAR and Cx43， especially in the high-dose group （P<0.01）， significantly elevated protein expression of MBP in the myelin sheath， and weakened fluorescence co-labeled by GFAP and Cx43， especially in the high-dose group. ConclusionModified SYW can improve the learning and memory abilities of VD rats， and the mechanism may be related to the inhibition of Cx43 expression， reduction of the release of Glu， inhibition of AMPAR-mediated inflammatory response to reduce the production of astrocyte marker GFAP， and promotion of the expression of MBP protein to alleviate myelin injury.

Enhancement of oligodendrocyte autophagy alleviates white matter injury and cognitive impairment induced by chronic cerebral hypoperfusion in rats

Cognitive impairment caused by chronic cerebral hypoperfusion (CCH) is associated with white matter injury (WMI), possibly through the alteration of autophagy. Here, the autophagy-lysosomal pathway (ALP) dysfunction in white matter (WM) and its relationship with cognitive impairment were investigated in rats subjected to two vessel occlusion (2VO). The results showed that cognitive impairment occurred by the 28th day after 2VO. Injury and autophagy activation of mature oligodendrocytes and neuronal axons sequentially occurred in WM by the 3rd day. By the 14th day, abnormal accumulation of autophagy substrate, lysosomal dysfunction, and the activation of mechanistic target of rapamycin (MTOR) pathway were observed in WM, paralleled with mature oligodendrocyte death. This indicates autophagy activation was followed by ALP dysfunction caused by autophagy inhibition or lysosomal dysfunction. To target the ALP dysfunction, enhanced autophagy by systemic rapamycin treatment or overexpression of Beclin1 (BECN1) in oligodendrocytes reduced mature oligodendrocyte death, and subsequently alleviated the WMI and cognitive impairment after CCH. These results reveal that early autophagy activation was followed by ALP dysfunction in WM after 2VO, which was associated with the aggravation of WMI and cognitive impairment. This study highlights that alleviating ALP dysfunction by enhancing oligodendrocyte autophagy has benefits for cognitive recovery after CCH.

Extracranial non-vestibular head and neck schwannomas: a case series with the review of literature

Abstract Introduction: Schwannomas are tumous that arise from Schwann cells. Schwannoma is one of the differential diagnosis for lateral neck swelling. Objective: In this study, we aim to describe the incidence, presenting clinical features and management of extracranial, non-vestibular schwannomas of head and neck region, along with the review of the literature. Methods: Patients treated at our tertiary care hospital for head and neck schwannomas for the past 15 years were included in the study. A review of literature on the extracranial head and neck schwannoma was also done. Results: Twenty-five cases were assessed in this study. Nineteen cases presented as a neck swelling during the initial evaluation. Vagus nerve was the most common nerve of origin, followed by the cervical sympathetic plexus. A rare presentation arising from brachial plexus C5 nerve root was also encountered. A few rare cases of schwannomas arose from the nasal cavity, paranasal sinuses, and oral cavity. Surgical excision was done in all the cases with histopathology suggestive of schwannoma. The nerve of origin of the tumor was identified in nineteen patients. Among them, 11 (58%) were from the vagus nerve, 7 (37%) from the cervical sympathetic chain, and 1 (4%) from the brachial plexus C5 nerve root. Conclusion: A long-standing unilateral neck mass is the most common presenting complaint in head and neck schwannoma. The diagnosis is mainly based on clinical features and investigations such as imaging. The mainstay of treatment is complete surgical excision. The diagnosis is confirmed on the histopathological study after excision of the lesion. Due to the proximity of the tumor with the involved nerve, palsy may occur. Hence, an accurate preoperative diagnosis of schwannoma is essential.

Liuwei Dihuangtang Alleviates Myelin Injury in vHIP and Depression-like Behavior of Diabetes Mellitus Combined with Comorbid Depression Rats via AMPK/Akt/GSK3β/Nrf2 Pathway / 中国实验方剂学杂志

ObjectiveTo observe the effect of Liuwei Dihuangtang on depression-like behavior of diabetes mellitus combined with comorbid depression （DD） rats， so as to explore its action mechanism. MethodFifty male SD rats of SPF grade were fed with high fat diet and injected with low-dose streptozotocin （STZ） via tail vein for inducing diabetes. Afterwards， the diabetic rats were exposed to chronic unpredictable mild stress （CUMS） for 28 d. The successfully modeled DD rats were randomly divided into five groups： model group， fluoxetine （10 mg·kg-1·d-1） group， and low-， medium-， and high-dose （3.375， 6.75， 13.5 g·kg-1·d-1） Liuwei Dihuangtang groups， with 10 in each group. Another 10 rats were classified into the normal control group and treated with intragastric administration of normal saline for four weeks. The tail suspension test and open field test were conducted to evaluate the depressive-like phenotype of rats. The contents of malondialdehyde （MDA）， reactive oxygen species （ROS）， 8-hydroxy-2 deoxyguanosine （8-OHdG）， superoxide dismutase （SOD）， and glutathione （GSH） in ventral hippocampus （vHIP） were measured by enzyme-linked immunosorbent assay （ELISA）， and the myelin basic protein （MBP） expression in vHIP by immunofluorescence assay. The expression levels of MBP， myelin protein lipoprotein （PLP）， myelin oligodendrocyte glycoprotein （MOG）， phosphorylated adenosine 5'-monophosphate-activated protein kinase （p-AMPK）/AMPK， phosphorylated protein kinase B （p-Akt）/Akt， phosphorylated glycogen synthase kinase 3β （p-GSK3β）/GSK3β， and nuclear factor erythroid-2 related factor 2（Nrf2） were determined by Western blotting. ResultCompared with the normal control group， the model group exhibited significantly prolonged immobility in the tail suspension test （P<0.01） and shortened residence at the central area in the open field test （P<0.01）. The immobility time in the medium- and high-dose Liuwei Dihuangtang groups declined to different degrees as compared with that of the model group （P<0.01）， while the residence time at the central area was significantly increased （P<0.05， P<0.01）. Compared with the normal control group， the model group displayed down-regulated MBP， PLP， and MOG protein expression in vHIP （P<0.01）. Compared with the model group， Liuwei Dihuangtang at the low dose up-regulated the expression of MBP （P<0.05）， but did not obviously affect the expression of MOG and PLP. Fluoxetine and Liuwei Dihuangtang at the medium and high doses up-regulated the expression of MBP， PLP， and MOG （P<0.05， P<0.01）. Comparison with the normal control group revealed that the MBP fluorescence intensity in vHIP of the model group was significantly weakened （P<0.01）. After the intervention， the MBP fluorescence intensities in the medium- and high-dose Liuwei Dihuangtang groups and fluoxetine group were enhanced in contrast to that of the model group （P<0.05， P<0.01）. SOD and GSH in the model group were lower than those in the normal control group （P<0.01）， whereas the MDA， ROS， and 8-OHdG expression levels were higher （P<0.01）. Compared with the model group， Liuwei Dihuangtang at the medium and high doses and fluoxetine all down-regulated the expression levels of MDA， ROS， and 8-OHdG （P<0.05，P<0.01）， while up-regulated SOD and GSH expression （P<0.05，P<0.01）. The expression levels of p-AMPK， p-Akt， and Nrf2 in the model group were down-regulated as compared with those in the control group， and the expression of p-GSK3β was up-regulated （P <0.01）. As demonstrated by comparison with the model group， the protein expression of p-AMPK in the low-dose Liuwei Dihuangtang group was elevated （P<0.05）， while p-Akt and Nrf2 were slightly increased， exhibiting no statistical significant difference. However， the protein expression levels of p-AMPK， p-Akt， and Nrf2 in the medium- and high-dose Liuwei Dihuangtang groups and fluoxetine group were up-regulated， while those of p-GSK3β were down-regulated （P<0.05，P<0.01）. ConclusionLiuwei Dihuangtang improves the depressive-like behavior of DD rats， which may be related to its activation of the AMPK/Akt/GSK3β/NRF2 pathway， regulation of the oxidative stress in vHIP， and enhancement of myelin repair.

Liuwei Dihuangtang Alleviates Myelin Injury in Anterior Cingulate Cortex and Depression-like Behaviors of Rats with Diabetes Mellitus and Depression via Promoting Autophagy and Regulating Microglial Phenotype / 中国实验方剂学杂志

ObjectiveTo observe the effect of Liuwei Dihuangtang （LWDHT） on depression-like behaviors of rats with diabetes mellitus and depression （DD） and explore its mechanism. MethodThe diabetes mellitus （DM） model was induced by the high-fat diet and tail vein injection of low-dose streptozotocin （STZ） in 50 male Sprague-Dawley rats of SPF grade. Then the DD model was induced by chronic unpredictable mild stress （CUMS） for 28 days in DM rats. Fifty DD rats were randomly divided into model group， fluoxetine group （10 mg·kg-1·d-1）， and low-， medium-， and high-dose LWDHT groups （3.375， 6.75， 13.5 g·kg-1·d-1）， with 10 rats in each group. Another 10 healthy rats were assigned into a control group and received normal saline by gavage. After four weeks of drug intervention， the forced swimming assay was carried out to assess the depression-like behaviors of rats. The expression levels of tumor necrosis factor-α （TNF-α）， interleukin-1β （IL-1β）， interleukin-4 （IL-4）， and interleukin-10 （IL-10） in the anterior cingulate cortex （ACC） were detected by enzyme-linked immunosorbent assay （ELISA）. Immunofluorescence was used to detect the expression of myelin basic protein （MBP） in ACC and the co-localization of ionized calcium-binding adapter molecule 1 （Iba1） with intracellular microtubule-associated protein 1 light chain 3 （LC3）. The protein expression levels of MBP， myelin proteolipid protein （PLP）， myelin oligodendrocyte glycoprotein （MOG）， Beclin-1， LC3， p62， and microglia （MG） phenotypic protein-related inducible nitric oxide synthase （iNOS）， and arginase 1 （Arg1） were detected by Western blot. ResultCompared with the control group， the model group showed shortened swimming time and prolonged immobility time （P<0.01）. Compared with the model group， the medium- and high-dose LWDHT groups showed reduced immobility time （P<0.05， P<0.01）. Compared with the control group， the model group showed decreased protein expression of MBP， PLP， and MOG in the ACC region （P<0.01）. Compared with the model group， the fluoxetine group and the medium- and high-dose LWDHT groups showed up-regulated protein expression of MBP， PLP， and MOG （P<0.05， P<0.01）. Compared with the control group， the model group showed decreased MBP fluorescence intensity in the ACC region （P<0.01）. Compared with the model group， the fluoxetine group and the medium- and high-dose LWDHT groups showed increased MBP fluorescence intensity in the ACC region （P<0.05， P<0.01）. Compared with the control group， the model group showed increased expression of iNOS （P<0.01） and slightly increased Arg1 protein expression. Compared with the model group， the medium- and high-dose LWDHT groups and the fluoxetine group showed down-regulated iNOS expression and up-regulated Arg1 protein expression （P<0.05， P<0.01）， but there was no significant difference between the fluoxetine group and the medium-，high-dose LWDHT groups. Compared with the control group， the model group showed increased expression levels of proinflammatory factors IL-1β and TNF-α in the ACC region （P<0.01） and slightly increased expression levels of anti-inflammatory factors IL-4 and IL-10. Compared with the model group， the fluoxetine group， and the medium- and high-dose LWDHT groups showed down-regulated expression of IL-1β and TNF-α （P<0.05， P<0.01） and up-regulated expression of IL-4 and IL-10 （P<0.05， P<0.01）. Compared with the control group， the model group showed reduced expression levels of Beclin-1 and LC3Ⅱ （P<0.01） and increased expression level of p62 （P<0.01）. Compared with the model group， the fluoxetine group and the medium- and high-dose LWDHT groups showed up-regulated Beclin-1 and LC3Ⅱ expression （P<0.01） and down-regulated p62 expression （P<0.01）. Compared with the control group， the model group showed decreased LC3+Iba1+ cells in the ACC region （P<0.01）. Compared with the model group， the fluoxetine group and the medium- and high-dose LWDHT groups showed increased LC3+Iba1+ cells （P<0.05， P<0.01）. ConclusionLWDHT can alleviate the depression-like behaviors in DD rats presumedly by promoting MG autophagy， regulating MG phenotypic changes， and increasing MG clearance of myelin sheath fragments. Meanwhile， MG phenotypic transformation also inhibits ACC inflammation in DD rats， improves the local microenvironment of oligodendrocyte proliferation and differentiation， and ultimately promotes the repair and remyelination of damaged myelin sheath.

Ultrastructural clarification of the peripherally located actin network in the myelinated axons / Aclaración ultraestructural de la red de actina localizada periféricamente en los axones mielinizados

SUMMARY: Despite the existence of a large amount of actin in the axons, the concentration F-actin was quite low in the myelinated axons and almost all the F-actin were located in the peripheries of the myelinated axons. Until now, the ultrastructural localization of F-actin has still not been reported in the myelinated axons, probably due to the lack of an appropriate detection method. In the present study, a phalloidin-based FITC-anti-FITC technique was adopted to investigate the subcellular localization of F-actin in the myelinated axons. By using this technique, F-actin is located in the outer and inner collars of myelinated cytoplasm surrounding the intermodal axon, the Schmidt-Lanterman incisures, the paranodal terminal loops and the nodal microvilli. In addition, the satellite cell envelope, which encapsulates the axonal initial segment of the peripheral sensory neuron, was also demonstrated as an F-actin-enriched structure. This study provided a hitherto unreported ultrastructural view of the F-actin in the myelinated axons, which may assist in understanding the unique organization of axonal actin cytoskeleton.

RESUMEN: A pesar de la existencia de una gran cantidad de actina en los axones, la concentración de F-actina era bastante baja en los axones mielinizados y casi la totalidad de F-actina se localizaba en las periferias de los axones mielinizados. A la fecha aún no se ha reportado la localización ultraestructural de F-actina en los axones mielinizados, probablemente debido a la falta de un método de detección apropiado. En el presente estudio, se adoptó una técnica FITC-anti-FITC basada en faloidina para investigar la localización subcelular de F-actina en los axones mielinizados. Mediante el uso de esta técnica, la F-actina se localiza en los collares externo e interno del citoplasma mielinizado que rodea el axón intermodal, a las incisiones de Schmidt-Lanterman,a las asas terminales paranodales y a las microvellosidades nodales. Además, la envoltura de la célula satélite, que encapsula el segmento axonal inicial de la neurona sensorial periférica, también se demostró como una estructura enriquecida con F-actina. Este estudio proporcionó una vista ultraestructural de la F-actina en los axones mielinizados, que puede ayudar a comprender la organización única del citoesqueleto de actina axonal.

Xiaoyaosan Promotes Myelin Regeneration and Alleviates Depressive Symptoms in Vascular Dementia Mice with Depression via Promoting Microglia Polarization / 中国实验方剂学杂志

Objective:To investigate the effect of Xiaoyaosan on depressive behavioral phenotype in mice with vascular dementia （VaD） mice and its possible mechanism. Method:Sixty three-month-old male C57/BL6 mice were divided into the normal control group， model group， positive control group， as well as low-， medium-， and high-dose Xiaoyaosan groups. Mice in all groups except for the normal control group underwent bilateral carotid artery stenosis. Two weeks later， they were subjected to chronic restraint stress， 6 h per day， for inducing VaD complicated with depression. Mice in the low-， medium-， and high-dose Xiaoyaosan groups were treatment with intragastric administration of Xiaoyaosan decoction （5， 10， 20 g·kg^-1）， the ones in the positive control group with fluoxetine （10 mg·kg^-1）， and those in the normal control group and model group with an equal volume of normal saline for four weeks， during which the restraint stress was maintained. The depressive behavioral phenotype of mice was observed in sugar water preference test and tail suspension test. The fluorescence expression of myelin basic protein （MBP） in ventral hippocampus （vHIP） was detected by fluorescence immunoassay. The ultrastructure of myelin sheath in vHIP was observed by transmission electron microscopy. The protein expression levels of MBP， myelin oligodendrocyte glycoprotein （MOG）， myelin-associated glycoprotein （MAG）， triggering receptor expressed on myeloid cells-2 （TREM2）， inducible nitric oxide synthase （iNOS）， arginase 1 （Arg1）， interleukin-I<italic>β</italic> （IL-1<italic>β</italic>）， tumor necrosis factor-<italic>α</italic> （TNF-<italic>α</italic>）， interleukin-4 （IL-4）， and interleukin-10 （IL-10） were assayed by Western blot. Result:As revealed by behavioral test， compared with the normal control group， the model group exhibited prolonged immobility time and decreased percentage of sugar water preference （<italic>P</italic><0.01）. Compared with the model group， Xiaoyaosan significantly shortened the immobility time of mice （<italic>P</italic><0.05） and increased the percentage of sugar water preference （<italic>P</italic><0.01）. Western blot results showed that the protein expression levels of MBP， MOG， and MAG in vHIP of the model group were remarkably decreased as compared with those of the normal control group （<italic>P</italic><0.01）. The protein expression levels of MBP， MOG， and MAG in vHIP of the low-dose Xiaoyaosan group were increased in contrast to those in the model group （<italic>P</italic><0.05， <italic>P</italic><0.01）， while the protein expression of iNOS was decreased （<italic>P</italic><0.01）. The protein expression levels of MBP， MOG， MAG， TREM2， Arg1， IL-4， and IL-10 in the medium- and high-dose Xiaoyaosan groups were up-regulated （<italic>P</italic><0.05， <italic>P</italic><0.01）， whereas those of iNOS， IL-1<italic>β</italic>， and TNF-<italic>α</italic> were down-regulated （<italic>P</italic><0.01）. The immunofluorescence findings demonstrated that the mean fluorescence intensity of MBP in the model group declined in comparison with that in the normal control group （<italic>P</italic><0.01）， while the mean fluorescence intensities of MBP in the low-， medium-， and high-dose Xiaoyaosan groups were enhanced to different degrees （<italic>P</italic><0.01）. It was observed under the transmission electron microscope that the myelin structure of the model group was loosened and the dense layer was separated and irregularly arranged. Xiaoyaosan improved the structural integrity of myelin sheath and the looseness of lamellar structure. Conclusion:Xiaoyaosan ameliorates the depressive behavioral phenotype of VaD mice， which may be related to the up-regulation of TREM2， the induction of M2 polarization of microglia cells， the enhancement of their anti-inflammatory and phagocytic abilities， and the promotion of damaged myelin sheath regeneration.

The modified method of luxol fast blue for paraffin-embedded myelin sheath staining / El método modificado de luxol fast blue para la tinción de mielina fijada en parafina

SUMMARY: Histological techniques are the study of animal and human tissues through staining and examining them under a microscope. To demonstrate the axonal degeneration and demyelination in histological studies, the Luxol Fast Blue staining is gold standard techniques. In this study, a new histochemical method based on modified Luxol Fast Blue for the staining of the myelin sheath in sciatic nerve tissues described. The sciatic nerves of rats were removed and then the sciatic nerve was immersed in 10 % formaldehyde for one week and embedded in paraffin block. Next, thin sections (5 µm) were cut, using a microtome and stained with conventional and modified Luxol Fast Blue. Our results showed that a new method of modified Luxol Fast Blue staining can accurately identify the myelin in the sciatic nerve fibers. The current study showed that the Luxol Fast Blue combination with Light Green has a good effect on myelin coloration, and the results of this study are comparable to LFB combination with Sirius red.

RESUMEN: Las técnicas histológicas son el estudio de tejidos animales y humanos mediante tinción y examen bajo un microscopio. Para demostrar la degeneración axonal y la desmielinización en estudios histológicos, la tinción Luxol Fast Blue es una técnica estándar de oro. En este estudio, se describe un nuevo método histoquímico basado en Luxol Fast Blue modificado para la tinción de mielina en los tejidos del nervio ciático. Se seccionaron los nervios ciáticos de ratas y luego el nervio ciático se sumergió en formaldehído al 10 % durante una semana y se fijó en bloque de parafina. Posteriormente, se cortaron secciones delgadas (5 µm) usando un microtomo y se tiñeron con Luxol Fast Blue convencional y modificado. Nuestros resultados mostraron que un nuevo método de tinción Luxol Fast Blue modificado puede identificar con precisión la mielina en las fibras del nervio ciático. El estudio actual mostró que la combinación Luxol Fast Blue con Light Green es un buen efecto sobre la coloración de mielina, y los resultados de este estudio son comparables a la combinación LFB con Sirius red.

Anatomical and ultrastructural sex differences in mean diameter and thickness of myelinated axons in adult rat corpus callosum / Diferencias sexuales anatómicas y ultraestructurales del diámetro medio y grosor de los axones mielinizados en el cuerpo calloso de ratas adultas

Sexual dimorphism exists at all levels of the nervous system. These sex differences could underlie genderrelated differences in behavior and neuropsychological function, as well as the gender differences in the prevalence of various mental disorders such as autism, attention deficit disorders, and schizophrenia. Myelination, on the other hand, is a unique cellular process that can have a dramatic impact on the structure and physiology of an axon and its surrounding tissue. The corpus callosum (CC) is the largest of the brain commissures, which connects the cerebral cortices of the two hemispheres, and provides interhemispheric connectivity for information transfer and processing between cortical regions. Variation in the axonal properties of CC will alter the interhemispheric connectivity. The CC consists of myelinated and unmyelinated axons, glial cells and blood vessels. Several functional studies have reported that the function of CC is associated with its axons density and myelination properties. The sexual dimorphism in the axonal content of the CC has always been controversial; hence, the aim of this study was to analyze the differences in axons' diameter and myelin sheath thickness of the CC between male and female rats. For this purpose, five pairs of adult male and female rats were perfused and the CC were removed and sectioned. Four sections from different subregions of the corpus callosum that represent the genu, anterior body, posterior body, and splenium of the CC were stained and electron microscopic images were captured using stereological guidelines. Later, the axons diameter and myelin sheath thickness for each subregion were calculated and compared between males and females. Our preliminary findings of the present study indicated region specific differences in the myelinated axon thickness and diameter in the CC between male and female rats.

El dimorfismo sexual existe en todos los niveles del sistema nervioso. Estas diferencias de sexo podrían ser la base de las diferencias de comportamiento y función neuropsicológica relacionadas con el sexo, así como las diferencias en la prevalencia de diversos trastornos mentales, como el autismo, los trastornos por déficit de atención y la esquizofrenia. La mielinización, por otro lado, es un proceso celular único que puede tener un impacto dramático en la estructura y fisiología de un axón y su tejido circundante. El cuerpo calloso (CC) es la mayor comisura cerebral, que conecta las cortezas cerebrales de ambos hemisferios, y proporciona la conectividad interhemisférica para la transferencia y el procesamiento de información entre regiones corticales. La variación en las propiedades axonales de CC alterará la conectividad interhemisférica. El CC consiste en axones mielinizados y no mielinizados, células gliales y vasos sanguíneos. Varios estudios funcionales han informado que la función de CC está asociada con la densidad de axones y las propiedades de mielinización. El dimorfismo sexual en el contenido axonal del CC siempre ha sido controvertido; por lo tanto, el objetivo de este estudio fue analizar las diferencias en el diámetro de los axones y el grosor de la vaina de mielina del CC entre ratas macho y hembra. Para este propósito, se perfundieron cinco pares de ratas macho y hembra adultas y se extrajeron y seccionaron las CC. Se tiñeron cuatro secciones de diferentes subregiones del cuerpo calloso que representan el genu, el cuerpo anterior, el cuerpo posterior y el esplenio y se capturaron imágenes de microscopía electrónicas utilizando referencias estereológicas. Posteriormente se calculó el diámetro de los axones y el grosor de la vaina de mielina para cada subregión y se compararon entre machos y hembras. Nuestros hallazgos preliminares del presente estudio indicaron diferencias específicas en el grosor y diámetro del axón mielinizado en el CC entre ratas macho y hembra.

Effectiveness of Flaxseed Oil on Peripheral Nerve Regeneration Following Crush Injury of Sciatic Nerve in Rat: Behavioural Analysis and an Electron Microscopic Study

@#Introduction: Peripheral nerve injuries (PNI) are a disabling injury as it often results in motor and sensory deficit with cognitive impairment. Flaxseed oil provides a good source of omega-3 fatty acid and it is believed to be able to protect the damaged nerve cell for successful nerve recovery. This study aimed to investigate a potential neuro-regeneration properties of flaxseed oil in treating the PNI. Methods: A total of 65 rats were separated into 4 groups: Group 1: Normal group (n=5), Group 2: Negative group (n=20), Group 3: Experimental group (n=20) and Group 4: Positive control (n=20), all the group were further divided into 4 groups (post-operative 7, 14, 21, 28 days, n=5 for each days). The functional restoration was assessed by walking track analysis (Sciatic Functional Index analysis-SFI) and toe spreading reflex (grading score). Electron microscope studies were performed on sciatic nerve to evaluate the regenerative process through morphologic and morphometric changes. Results: Oral administration of flaxseed oil (experimental group) at 1000 mg/kg body weight/day showed better recovery compared to negative control value. However, there was no significant difference in SFI and toe spreading reflex between positive (mecobalamin) and experimental group (flaxseed oil). Morphological and morphometrical findings indicated increases in the myelin thickness and myelin sheath layer after administration of flaxseed oil. Conclusion: The flaxseed oil supplementation could enhance the neurorestorative capacities of injured sciatic nerve.

Olfactory ensheathing cell transplantation promotes the ultrastructure repair at the lesion site of rat models of spinal cord injury / 中国组织工程研究

BACKGROUND: Olfactory ensheathing cell transplantation for treating spinal cord injury is an issue of concern, which mainly explores the changes of microenvironment after spinal cord injury. However, the effect of olfactory ensheathing cell transplantation on the ultrastructure of spinal cord after spinal cord injury is never reported. OBJECTIVE: To investigate the ultrastructure alterations of neurocytes, axons, myelin sheaths, synapses, and glial scar after spinal cord Injury, and the effect of olfactory ensheathlng cell transplantation on the protection and regeneration of nerve repair after spinal cord Injury. METHODS: The study was approved by the Ethical Committee of Biomedicine of Medical Department of Xi’an Jiaotong University, approval No. 2018-2048. Twenty female Sprague-Dawley rats were divided into three groups: Blank control group (n=4, complete laminectomy of T10, partial laminectomy of Tg and Tn), DF12 group (n=B, cordotomy+injection of DF12 solution), and olfactory ensheathing cell transplantation group (n=8, cordotomy+olfactory ensheathing cell transplantation). The spinal cord was removed under anesthesia to observe the ultrastructure alterations of neurocytes under transmission electron microscope at 1, 7, 28 and 56 days after injury. RESULTS AND CONCLUSION: (1) Compared with the blank control group, the organelles in the neurons of the injured lesions were significantly reduced, and the obvious changes were found in the ultrastructure of axon, synapses and myelin sheath in the DF12 group. In the olfactory ensheathing cell transplantation group, the organelles in the neurons of the injured lesions were significantly increased with obvious nucleolus, the regeneration of axon, myelin sheath and synapses were significantly promoted, and the glial scar was significantly decreased. (2) The degree of reaction of the astrocytes and pericytes in the olfactory ensheathing cell transplantation group was light. (3) These findings suggest that olfactory ensheathing cell transplantation can effectively protect the nerve tissues in the lesions after spinal cord injury, promote the regeneration of axon, myelin sheath and synapses, and inhibit the hyperplasia of astrocytes and pericytes, so that the post-injury microenvironment is available for the regeneration of neurons, axons and synapses.

Insight into white matter changes in Alzheimer’s disease: A focus on myelin and oligodendrocyte / 中国组织工程研究

BACKGROUND: In previous studies Alzheimer’s disease was considered as a typical disease of the brain gray matter, and most attention has focused on the pathological and neuroimaging changes of gray matter in Alzheimer’s disease. Recently, in addition to neuronal loss, white matter degeneration and demyelination may be important pathophysiological features in the progress of Alzheimer’s disease. To date, much attention has been paid to the changes of white matter in Alzheimer’s disease. OBJECTIVE: To elucidate the evidence for extensive white matter abnormalities in Alzheimer’s disease and its mechanism, and to discuss the relationship between white matter changes and cognitive function. METHODS: A computer-based retrieval was performed by the first author in PubMed and CNKI databases to search related papers published from January 1998 to April 2019 using the keywords of “Alzheimer’s disease, white matter injury, neurodegeneration, oligodendrocyte” in English and Chinese, respectively. Articles related to Alzheimer’s disease, white matter abnormalities, the mechanism of oligodendrocyte death and the relationship between white matter changes and cognitive function were selected. A total of 41 relevant literatures were retrieved. RESULTS AND CONCLUSION: White matter abnormalities widely occur in Alzheimer’s disease patients, which are probably the earliest pathological changes. White matter lesions are of important significance in the pathology and pathogenesis of Alzheimer’s disease. Several mechanisms such Aβ toxicity and tauopathy, oxidative stress, excitotoxicity, and iron overload can affect oligodendrocytes, resulting in myelin loss. Altering axonal conduction by demyelination or axonal damage can directly and/or indirectly affect cognition. In conclusion, white matter changes are closely related to cognitive impairment. Explorations on the relationship between white matter changes and the hallmark of Alzheimer’s disease cannot only provide theoretical evidence for Alzheimer’s disease pathogenesis, but also develop a new therapeutic approach for Alzheimer’s disease.

Effects of Three Handing-Three Points on Motor Function and Expression of Transforming Growth Factor-β1/Smad2 Pathway in Injured Sciatic Nerve of Rats / 中国康复理论与实践

Objective:To investigate the effect of Tuina of Three Handing-Three Points on the motor function of hind limbs, the proliferation of Schwann cell, recovery of myelin sheath and the expression of transforming growth factor (TGF)-β1/Smad2 pathway protein in injured sciatic nerve of rats. Methods:A total of 66 male Sprague-Dawley rats were randomly divided into sham operation group (n = 22), model group (n = 22) and observation group (n = 22). The sciatic nerve injury model was made by clamping method. On the eighth day after modeling, the observation group received stimulation on Yinmen (BL37), Chengshan (BL57) and Yanglingquan (GB34). The sciatic functional index (SFI) was measured before intervention and 21 days after intervention. The Oblique Plate Test was performed before intervention, and seven days, 14 days and 21 days after intervention. The expression of S100, TGF-β1 and Smad2 were observed by immunofluorescence. The expression of TGF-β1, Smad2 and p-Smad2 was detected by Western blotting. Results:Before intervention, SFI was lower in the model group and observation group than in the sham operation group (P < 0.05); 21 days after intervention, SFI and the angle of Oblique Plate Test were higher in the observation group than in the model group (P < 0.05). Immunofluorescence showed that, 21 days after intervention, the expression of S100 was lower in the model group than in the sham operation group (P < 0.01), and was higher in the observation group than in the model group (P < 0.05), no difference was found between the observation group and the sham operation group (P > 0.05). Western blotting showed that, before intervention and seven days after intervention, the expression of TGF-β1, Smad2 and p-Smad2 were higher in the model group than in the sham operation group; 21 days after intervention, no difference was found in the expression among groups (P > 0.05) Conclusion:Three Handing-Three Points could promote the proliferation of Schwann cell and the recovery of myelin sheath, to improve the motor function of hind limbs in rats with sciatic nerve injury, which may not be related to TGF-β1/Smad2 pathway.

Effects of Three Handing-Three Points on Thickness of Myelin Sheath and Expression of Neuregulin 1 and Human Epidermal Growth Factor Receptor 2 after Sciatic Nerve Injury in Rats / 中国康复理论与实践

Objective:To explore the effect of Tuina of Three Handing-Three Points on the recovery of motor function, the expression of neuregulin (NRG) 1 and human epidermal growth factor receptor (ErbB) 2 in the injured point of sciatic nerve and L4-6 spinal cord, and the morphological change of myelin sheath at the injured point of sciatic nerve of rats. Methods:A total of 76 male Sprague-Dawley rats were randomly divided into normal group, sham operation group, model group and Tuina group with 19 rats in each group. The right side sciatic nerve was clamped to make model in the model group and Tuina group. The sham operation group exposed sciatic nerve only. Tuina group received Tuina on Yinmen (BL37), Chengshan (BL57) and Yanglingquan (GB34) with dialing, plucking and kneading using Tuina technique simulator. All of them were tested with Oblique Plate Test before modeling, seven days and 28 days after modeling. Western blotting was used to detect the protein expression of NRG1 and ErbB2 in the injured point of sciatic nerve and L4-6 spinal cord. The change of myelin sheath at the sciatic nerve injury point was observed and analyzed by transmission electron microscope. Results:Seven days and 28 days after modeling, the scores of Oblique Plate Test were lower in the model group and Tuina group than in the normal group and the sham operation group (P < 0.05); 28 days after modeling, the scores was higher in Tuina group than in the model group (P < 0.05). At the sciatic nerve injury point, three days after modeling, the expression of NRG1 and ErbB2 was higher in the model group and Tuina group than in the normal group and the sham operation group (P < 0.05); seven days and 28 days after modeling, there was no significant difference in NRG1 among groups (P > 0.05); 28 days after modeling, the expression of ErbB2 was higher in the model group and Tuina group than in the normal group and the sham operation group (P < 0.05). In L4-6 spinal cord, three days after modeling, the expression of NRG1 and ErbB2 was higher in the model group and Tuina group than in the normal group and sham operation group (P < 0.05); seven days after modeling, the expression of NRG1 was higher in the model group and Tuina group than in the sham operation group (P < 0.05), and the expression of ErbB2 was higher in the model group and Tuina group than in the normal group and the sham operation group (P < 0.05); 28 days after modeling, the expression of NRG1 was higher in Tuina group than in the model group (P < 0.05), and there was no significant difference in ErbB2 among groups (P > 0.05). The electron microscope showed that, 28 days after modeling, the myelin sheath collapsed seriously in the model group; while the ultrastructure of the nerve injury point improved, and the myelin sheath of the nerve fiber was relatively intact in Tuina group; the g-ratio value was lower in the model group than in the sham operation group (P < 0.05), the g-ratio value was higher in Tuina group than in the model group (P < 0.05), and no difference was found in g-ratio value between Tuina group and sham operation group (P > 0.05). Conclusion:Three Handing-Three Points could improve the motor function of hind limbs in rats with sciatic nerve injury, which may be related to the adjustment of NRG1 and ErbB2 in the sciatic nerve and spinal cord, to maintain normal myelin sheath structure.

Multiple sclerosis has a distinct lipid signature in plasma and cerebrospinal fluid / Esclerose múltipla tem uma assinatura lipídica distinta no plasma e no líquido cefalorraquiano

ABSTRACT The diagnosis of multiple sclerosis (MS) has changed over the last decade, but remains a composite of clinical assessment and magnetic resonance imaging to prove dissemination of lesions in time and space. The intrathecal synthesis of immunoglobulin may be a nonspecific marker and there are no plasma biomarkers that are useful in the diagnosis of MS, presenting additional challenges to their early detection. Methods We performed a preliminary untargeted qualitative lipidomics mass spectrometry analysis, comparing cerebrospinal fluid (CSF) and plasma samples from patients with MS, other inflammatory neurological diseases and idiopathic intracranial hypertension. Results Lipid identification revealed that fatty acids and sphingolipids were the most abundant classes of lipids in the CSF and that glycerolipids and fatty acids were the main class of lipids in the plasma of patients with MS. The area under the curve was 0.995 (0.912-1) and 0.78 (0.583-0.917), respectively. The permutation test indicated that this ion combination was useful for distinguishing MS from other inflammatory diseases (p < 0.001 and 0.055, respectively). Conclusion This study concluded that the CSF and plasma from patients with MS bear a unique lipid signature that can be useful as a diagnostic biomarker.

RESUMO Embora o diagnóstico da EM tenha se modificado na última década, ainda tem como requisito básico a demonstração da disseminação no tempo e no espaço, através do quadro clínico e do exame de ressonância magnética. A síntese intratecal de imunoglobulina pode ser um marcador inespecífico e não há biomarcadores plasmáticos que sejam úteis no diagnóstico da EM, impondo desafios à sua detecção precoce. Métodos Realizamos uma análise lipidômica preliminar por espectrometria de massas, não direcionada, qualitativa, comparando amostras de LCR e plasma de pacientes com EM, outras doenças neurológicas inflamatórias e hipertensão intracraniana idiopática (HII). Resultados A identificação lipídica revelou que os ácidos graxos e esfingolipídios foram as classes mais abundantes de lipídios no LCR e que glicerolipídios e ácidos graxos foram a principal classe de lipídios no plasma de pacientes com EM. A AUC foi de 0,995 (0,912-1) e 0,78 (0,583-0,917), respectivamente. O teste de permutação indicou que essa combinação de íons foi útil para distinguir a EM de outras doenças inflamatórias (p < 0,001 e 0,055, respectivamente). Conclusão Este estudo sugere que o líquido cefalorraquidiano (LCR) e o plasma de pacientes com EM possuem uma assinatura lipídica única, pode ser útil como um biomarcador diagnóstico.

O desafio para compreender a morfologia cerebral: da visualização à quantificação / Challenges in understanding brain morphology: from visualization to quantification

O objetivo deste trabalho é estudar a morfologia neuronal a partir de modelos animais, fornecer informações biológicas difíceis de serem obtidas em humanos, permitindo estudar condições neuropsiquiátricas como doença de Alzheimer, ansiedade, dentre outras. O presente trabalho descreveu metodologia de estudo para cérebro de roedores, duas técnicas neuroanatômicas, Klüver-Barrera e Golgi-Cox, e seus respectivos processos de quantificação. A técnica de Klüver-Barrera permitiu visualização da substância branca e cinzenta com destaque na bainha de mielina. A técnica de Golgi-Cox, adaptada para realidade de nosso laboratório, mostrou-se eficiente para visualização de neurônios e seus prolongamentos, como dendritos e espinhas dendríticas, permitindo assim a quantificação. A partir de imagens obtidas de microscópio descreveu-se os diferentes passos para quantificação, a determinação de volume de estruturas internas cerebrais (corpo caloso e camada celular do hipocampo) assim como a quantificação das espinhas dendríticas em neurônios piramidais. Os métodos descritos e detalhados poderão ser utilizados em vários campos da neurociência

Neuronal morphology is analyzed in animal models to provide biological information difficult to obtain in humans. The above makes possible the study of neuro-psychiatric, such as Alzheimer´s disease, anxiety and others. Current study described methodology for rodents´ brains, two neuro-anatomic techniques, Klüver-Barrera and Golgi-Cox, and their respective quantification processes. Klüver-Barrera technique visualized the white and gray matter, particularly the myelin sheath. Golgi-Cox technique, adapted for current research, was efficient to visualize neurons and their prolongations, such as dendrites and dendritic spines, with quantification. Images by microscope described the different steps for the quantification, determination of volume of the brain´s internal structures (callous body and the hypocampus´s cell layer) coupled to the quantification of dendritic spines in pyramid neurons. Described and detailed methods will be useful in several fields of neuroscience

Effect of electroacupuncture combined with Schwann cell transplantation on limb locomotor ability, regional remyelination and expression of spinal CD4 and CD8 proteins in compressive spinal injury rats / 针刺研究

OBJECTIVE: To observe the effect of electroacupuncture (EA) combined with transplantation of Schwann cells (SCs) on limb locomotor, myelin sheath repair and expression of CD4 and CD8 in compressed spinal cord injury (CSCI) rats, so as to explore its mechanisms underlying improvement of CSCI. METHODS: A total of 45 female SD rats were randomly divided into normal control, model, EA, Schwann cell (SC) transplantation, and EA＋SC transplantation groups (n＝9 rats in each group). The CSCI model was established by laminectomy at T12-L2 and clip compression. Rats of the SC transplantation group accepted injection of the cultured SC suspension (2×106/6 µL) into the central, upper and lower sites of the injured spinal cord (5 mm in depth) 7-8 days after CSCI modeling. EA (2 Hz) was applied to bilateral "Zusanli" (ST36) and "Sanyinjiao" (SP6) for 10 min, once daily and 6 days a week for 3 weeks. The Basso, Beattie and Bresnahan locomotor rating scale (BBB scale) was used to evaluate the function state of CSCI. Morphological changes of the regional injured tissue were observed under light microscope after H．E. staining. The myelin sheath repair state and survival of SCs were detected by Luxol fast blue (LFB) staining and immunofluorescence histochemistry, and the expression of CD4, CD8 and P0 of the injured spinal cord was detected by Western blot. RESULTS: Compared with the normal control group, the BBB scores at the time-points of 0 d, and 1, 2, and 3 weeks were significantly decreased in the model group (P0.05). LFB staining showed a disordered arrangement of the nerve fibers in the white matter, myelinociasis and obvious decrease of the medullated fibers in the model group, and these situations were relatively milder in both EA and SC transplantation groups and obviously milder in the EA＋SC transplantation group. H．E. staining displayed that the structure of the injured region of the spinal cord was incomplete, accompanied with a large number of defect cavities and neuronal karyopyknosis in the model group, while the structure was relatively clear, with an increase of the normal neurons and fewer neuronal karyopyknosis in the EA＋SC transplantation group. Compared with the normal control group, MBP in the model group was significantly decreased (P0.05), while after the intervention and in comparison with the model group, the expression levels of P0 protein were significantly increased in the EA, SC transplantation and EA＋SC transplantation groups (P<0.05), and was significantly higher in the EA＋SC transplantation group than in both EA and SC transplantation groups (P<0.05). The expression levels of CD4 and CD8 proteins were significantly lower in the EA＋SC transplantation group than in the SC transplantation group (P<0.05)．. CONCLUSION: EA＋SCs transplantation can improve the locomotor function in CSCI rats, which may be related to its effects in increasing the survival of transplanted SCs to promote the remyelination and in reducing the immune rejecting reaction.

Effect of propofol on myelin basic protein expression and myelination of oligodendrocytes in neonatal SD rats / 南方医科大学学报

OBJECTIVE@#To investigate the effects of different doses of propofol on myelin basic protein (MBP) synthesis and myelination of oligodendrocytes in neonatal SD rats.@*METHODS@#A total of 57 neonatal SD rats (7 days old) were randomly divided into control group (=13), vehicle (fat emulsion) group (=5), and 25, 50 and 100 mg/kg propofol groups (=13 in each group). Eight hours after a single intraperitoneal injection of propofol or the vehicle, the rats were examined for expressions of mRNA, caspase-3 mRNA, cleaved caspase-3 and MBP in the brain tissues using qPCR and Western blotting. Immunofluorescence assay was used to detect the apoptosis of the oligodendrocytes at 8 h after the injection and the myelination of the corpus callosum and internal capsule at 24 h.@*RESULTS@#Compared with the control group, the neonatal rats with propofol injections showed significantly down-regulated expressions of mRNA and MBP protein in the brain tissue ( < 0.05). Propofol dose-dependently increased the transcription level of caspase-3 and the protein levels of cleaved caspase-3 at 8 h after the injection ( < 0.05). Propofol injection significantly increased the apoptosis of the oligodendrocytes, and the effect was significantly stronger in 50 and 100 mg/kg groups than in 25 mg/kg group ( < 0.05). At 24 h after propofol injection, myelin formation was significantly decreased in the corpus callosum of the neonatal rats in 100 mg/kg propofol group and in the internal capsule in 50 and 100 mg/kg groups ( < 0.05).@*CONCLUSIONS@#In neonatal SD rats, propofol can dose-dependently promote oligodendrocyte apoptosis, decrease MBP expressions in the brain, and suppress myelin formation in the corpus callosum and the internal capsule.