Impairment induction by axotomy in motor functional and histological anterior horn of spinal cord structure / Inducción del deterioro por axotomía en la estructura motora funcional e histológica del asta anterior de la médula espinal

We have surveyed the motor changes in rats subjected to sciatic nerve axotomy. The rats were divided into two groups, each one consisting of ten animals, which underwent the following intervention: The first group (control): healthy rats without any injuries and experimental group: rats with injured sciatic nerve without treatment. at 12 weeks, the L4 and L5 spinal cord segments were removed. We evaluated nerve function using muscle electromyography (EMG) activity and sciatic function index (SFI) simultaneously with histological spinal cord analyses by stereological methods at 12 week. After nerve injury presented gross locomotor deficits at week 12. We also found that the volume of the anterior horn of spinal cord and total number of motor neurons were decreased after nerve axotomy (p<0.05). In conjunction, these results indicate that peripheral nerve injuries have more severe consequences on hind limb motor output.

En este estudio se examinaron los cambios motores en ratas sometidas a axotomía del nervio ciático. Las ratas se dividieron en dos grupos diez animales. El primer grupo (control) eran ratas sanas sin lesiones, y el grupo experimental consistió en ratas con nervio ciático lesionado sin tratamiento. A las 12 semanas, los segmentos de la médula espinal L4 y L5 fueron removidos. Se evaluó la función nerviosa mediante electromiografía muscular (EMG) y el índice de función ciática (IFC), simultáneamente con análisis histológicos de la médula espinal mediante métodos estereológicos. A las 12 semanas de la lesión nerviosa presentó déficit locomotor grueso. Además, se observó que el volumen del asta anterior y el número total de neuronas motoras disminuyeron después de la axotomía nerviosa (P <0,05). En conjunto, estos resultados indican que las lesiones de los nervios periféricos determinan graves consecuencias de la función motora de los miembros posteriores.

Protective effect of cataractogenic lens injury on RGCs in optic nerve axotomy eye in vivo and its mechanism / 中华实验眼科杂志

Background It has been reported that murine Müller cells conditional medium can promote the survival of retinal ganglion cells (RGCs) and the regeneration of axons,and the survival rate of RGCs improve in the optic nerve axotomy eyes with cataractogenic lens injury in vitro.However,the interaction of Müller cells with pricking of lens in protecting RGCs is unclear.Objective The aim of this study was to investigate the role of Müller cells on survival of RGCs in the optic nerve axotomy with cataractogenic lens injury.Methods Forty-eight clean adult Wistar rats were randomized into sham operation group,optic nerve axotomy group and lens injury combined with optic nerve axotomy group.The optic nerve was exposed only in the rats of the sham operation group,optic nerve was completely transected at 3 mm behind the eyeball in the rats of the optic nerve axotomy group,and lens puncture and optic nerve axotomy were performed in the eyes of lens injury combined with optic nerve axotomy group.The rats were sacrificed at day 7 and day 14 after operation to prepare the retinal specimens.The RGCs were examined and counted by hematoxylin-eosin staining.Müller cells labeled by glial fibrillary acidic protein (GFAP) were counted using immunohistochemisty.Results The number of RGCs was (52.98 ± 1.90) /field and (51.81 ±3.09) /field on the 7th and 14th day in the sham operation group,without significant difference between them (t =0.910,P =0.378).The number of RGCs was significantly lower on the 14th day ([22.67±1.94] /field) than that of the 7th day ([36.61±1.69] /field) in the optic nerve axotomy group (t=15.312,P=0.000).Also,the number of RGCs was (50.76±2.77) /field and (35.69±1.80) /field on the 7th and 14th day in the lens injury combined with optic nerve axotomy group,showing a significant difference between the two timepoints (t =12.920,P =0.000).In addition,the RGCs number in the lens injury combined with optic nerve axotomy group was significantly higher than that in the optic nerve axotomy group both on 7 days and 14 days after operation (7 days:t =102.840,P =0.000; 14 days:t =164.020,P =0.000),and the number of RGCs was lower in the lens injury combined with optic nerve axotomy group than that of the sham operation group on day 14 (t =187.040,P =0.034).None of GFAP-labeled Müller cell was seen in sham operation group at both on 7 days and 14 days after operation,but a significant difference was found in the optic nerve axotomy group between the two timepoints ([29.38 ± 2.04]/field vs.[19.07 ± 2.14]/field ; t =-9.868,P=0.000).No significant difference in the number of the GFAP-labeled Müller cells was found in the lens injury combined with optic nerve axotomy group between 7 days and 14 days after operation([48.96±2.80] /field vs.[46.73±1.50]/field,t=1.987,P=0.067).In postoperative 7 days and 14 days after operation,the number of GFAP-labeled Müller cells increased in the lens injury combined with optic nerve axotomy group compared with the optic nerve axotomy group (7 days:t =-15.997,P=0.000; 14 days:t=-29.938,P=0.000).Conclusions In optic nerve axotomy with cataractogenic lens injury eye,the punctural injury of lens induce the activity of Müller cells and further promote the survival of RGCs in the cataratogenic lens injury combined with optic nerve axotomy rat eyes.

Effects of sciatic nerve transection on ultrastructure, NADPH-diaphorase reaction and serotonin-, tyrosine hydroxylase-, c-Fos-, glucose transporter 1- and 3-like immunoreactivities in frog dorsal root ganglion

Frogs have been used as an alternative model to study pain mechanisms. Since we did not find any reports on the effects of sciatic nerve transection (SNT) on the ultrastructure and pattern of metabolic substances in frog dorsal root ganglion (DRG) cells, in the present study, 18 adult male frogs (Rana catesbeiana) were divided into three experimental groups: naive (frogs not subjected to surgical manipulation), sham (frogs in which all surgical procedures to expose the sciatic nerve were used except transection of the nerve), and SNT (frogs in which the sciatic nerve was exposed and transected). After 3 days, the bilateral DRG of the sciatic nerve was collected and used for transmission electron microscopy. Immunohistochemistry was used to detect reactivity for glucose transporter (Glut) types 1 and 3, tyrosine hydroxylase, serotonin and c-Fos, as well as nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-diaphorase). SNT induced more mitochondria with vacuolation in neurons, satellite glial cells (SGCs) with more cytoplasmic extensions emerging from cell bodies, as well as more ribosomes, rough endoplasmic reticulum, intermediate filaments and mitochondria. c-Fos immunoreactivity was found in neuronal nuclei. More neurons and SGCs surrounded by tyrosine hydroxylase-like immunoreactivity were found. No change occurred in serotonin- and Glut1- and Glut3-like immunoreactivity. NADPH-diaphorase occurred in more neurons and SGCs. No sign of SGC proliferation was observed. Since the changes of frog DRG in response to nerve injury are similar to those of mammals, frogs should be a valid experimental model for the study of the effects of SNT, a condition that still has many unanswered questions.

The influence of selected pathological states on the somatostatin-like immunoreactive (SOM-LI) endocrine cells in the mucosal layer of the porcine descending colon

This study reports on changes in the number of somatostatin-like immunoreactive (SOM-LI) endocrine cells in the porcine descending colon, caused by chemically driven inflammation, axotomy and proliferative enteropathy (PE). The distribution pattern of SOM-LI endocrine cells has been studied using the routine single-labelling immunofluorescence technique. Semi-quantitative evaluation of the number of the SOM-immunostained endocrine cells within the mucosal layer of the porcine descending colon has been based on counting of all endocrine cells immunoreactive to SOM per unit area (0,1 mm²). Under physiological conditions the number of SOM-LI endocrine cells has been shown to constitute 3,30±0,22. All applied pathological processes resulted in changes in the SOM-like immunoreactivity, which varied in particular processes studied. The number of SOM-LI endocrine cells increased to 6,28±0,31 and 4,43±0,35 during chemically driven inflammation and proliferative enteropathy, respectively, and decreased to 1,17%±0,16 after axotomy. The obtained results suggest that SOM-LI endocrine cells may participate in various pathological states within porcine descending colon and their functions probably depend on the type of pathological factor.(AU)

Establishment of a model for axonal regeneration following mechanical transection in vitro / 中华创伤杂志

Objective To establish a model fit for axonal regeneration research after its mechanical injury.Methods Cortical explants from mice were planted on culture dishes by microglass pipettes or routine glass pipettes.The cell body and dendrites in axonal area were detected by immunofluorescence and RT-PCR.Besides,purity of regenerated axons was also tested by immunofluorescence and RT-PCR after mechanical transection of axons under microscopy.Results Compared with explants planting by routine glass pipettes,in the outside 1/2 axons of explants planted by micro-glass pipettes,the immunofluorescence and RT-PCR showed negative nucleus and dendrites.In the regenerated axons following mechanical transection of explants planted by micro-glass pipette,the immunofluorescene and RT-PCR showed no regenerated axons nucleus mixed into the dendrites and nucleus.Conclusions Explants planted by micro-glass pipette obtains enough pure axons and regenerated axons.The establishment of models of axonal mechanical transection lays foundation for its molecular study after trauma.

Axonal regeneration style and speed after axonal transaction: a preliminary study / 中华创伤杂志

ObjectiveTo establish a central nervous system axonal mechanical transection model in vitro and observe the axonal regeneration style and speed following the transection. MethodsThe cortical explants the mice were cultured in vitro,of which the axon and dendrite parts were marked using immunofluorescence.The model was built by mechanically transecting the axons and removing the severed axons.The axonal regeneration style was observed by tracing the undeveloped cellular bodies adhering to the residual axonal surface.The growth speed of the regenerated axons and normal axons were measured as well.Results ( 1 ) After mechauically transecting the axons of explants,the axonal regeneration was largely founded at the transected line.The undeveloped cellular bodies went over the transected line and spread to the distal area with axonai regeneration. (2) The axonal growth speed was (118 ± 32) μm/d and (72 ±41) μm/d in the transection group,but was (41 ± 17) μm/d and (32 ± 19) μm/d in the control group at 24 and 48 hours respectively. ConclusionThe regeneration style of the transected axons is the extension of the axonal stumps,rather than sprouting growth,and the growth speed is faster than that of the normal axons.

Co-localization of activating transcription factor 3 and phosphorylated c-Jun in axotomized facial motoneurons / 대한해부학회지

Activating transcription factor 3 (ATF3) and c-Jun play key roles in either cell death or cell survival, depending on the cellular background. To evaluate the functional significance of ATF3/c-Jun in the peripheral nervous system, we examined neuronal cell death, activation of ATF3/c-Jun, and microglial responses in facial motor nuclei up to 24 weeks after an extracranial facial nerve axotomy in adult rats. Following the axotomy, neuronal survival rate was progressively but significantly reduced to 79.1% at 16 weeks post-lesion (wpl) and to 65.2% at 24 wpl. ATF3 and phosphorylated c-Jun (pc-Jun) were detected in the majority of ipsilateral facial motoneurons with normal size and morphology during the early stage of degeneration (1-2 wpl). Thereafter, the number of facial motoneurons decreased gradually, and both ATF3 and pc-Jun were identified in degenerating neurons only. ATF3 and pc-Jun were co-localized in most cases. Additionally, a large number of activated microglia, recognized by OX6 (rat MHC II marker) and ED1 (phagocytic marker), gathered in the ipsilateral facial motor nuclei. Importantly, numerous OX6- and ED1-positive, phagocytic microglia closely surrounded and ingested pc-Jun-positive, degenerating neurons. Taken together, our results indicate that long-lasting co-localization of ATF3 and pc-Jun in axotomized facial motoneurons may be related to degenerative cascades provoked by an extracranial facial nerve axotomy.

Expressão do complexo de histocompatilidade principal de classe I (MHC I) no sistema nervoso central: plasticidade sináptica e regeneração / Expression of class I major histocompatibility complex (MHC I) in the central nervous system: role in synaptic plasticity and regeneration / Expresión del complejo principal de histocompatibilidad de clase I (MHC I) en el sistema nervioso central: plasticidad sináptica y regeneración

Foi demonstrado recentemente que o complexo de histocompatibilidade principal de classe I (MHC I), expresso no sistema nervoso central (SNC), não funciona somente como molécula com papel imunológico, mas também como parte de um mecanismo envolvido na plasticidade sináptica. A expressão de MHC I interfere na intensidade e seletividade da retração de sinapses em contato com neurônios que sofreram lesão e também influencia a reatividade das células gliais próximas a esses neurônios. A intensidade do rearranjo sináptico e resposta glial após lesão, ligadas à expressão de MHC I no SNC, repercute em diferenças na capacidade regenerativa e recuperação funcional em linhagens de camundongos isogênicos. Dessa forma, os novos aspectos sobre a função do MHC I no SNC direcionam futuras pesquisas no sentido de buscar o envolvimento do MHC I em doenças neurológicas e também o desenvolvimento de novas estratégias terapêuticas.

It has been recently demonstrated that the major histocompatibility complex of class I (MHC I) expressed in the central nervous system (CNS) does not only function as a molecule of the immune system, but also plays a role in the synaptic plasticity. The expression of MHC I influences the intensity and selectivity of elimination of synapses apposed to neurons that were subjected to lesion, besides influencing the reactivity of neighboring glial cells. MHC I expression and the degree of synaptic rearrangement and glial response after injury correlate with differences in the regenerative potential and functional recovery of isogenic mice strains. In this way, the new aspects regarding MHC I functions in the CNS may guide further studies aiming at searching the involvement of MCH I in neurologic disorders, as well as the development of new therapeutic strategies.

El complejo mayor de histocompatibilidad de clase I (MHC I), expresado en el sistema nervioso central (SNC), no sólo funciona como una molécula con función inmunológica, sino que es crucial para las respuestas del tejido nervioso en casos de lesiones. El MHC I está involucrado con los procesos de plasticidad sináptica y las células gliales en el microambiente de la médula espinal después de realizada axotomía periférica. La expresión de MHC I interfiere con la intensidad y la forma en que se producen la contracción y la eliminación de sinapsis con relación a las neuronas, cuyos axones se han comprometido, y también influye en la reactividad de las células gliales, cerca de estas neuronas. La intensidad de estos cambios, que responden a la expresión de MHC I en el SNC, implica diferencias en la capacidad de regeneración axonal de las células dañadas por axotomía, por lo que el nivel de expresión de las moléculas MHC I se relaciona con el proceso de regeneración de los axones y, en consecuencia, con la recuperación funcional. Por consiguiente, estos nuevos aspectos sobre la función del MHC I en el SNC orientan nuevas investigaciones con miras a entender el papel del MHC I en las enfermedades neurológicas y a desarrollar nuevas estrategias terapéuticas.

S100ß and fibroblast growth factor-2 are present in cultured Schwann cells and may exert paracrine actions on the peripheral nerve injury / S100ß e fator de crescimento de fibroblasto-2 estão presentes nas células de Schwann cultivadas e exercem ações parácrinas na lesão do nervo

PURPOSE: The neurotrophic factor fibroblast growth factor-2 (FGF-2, bFGF) and Ca++ binding protein S100ß are expressed by the Schwann cells of the peripheral nerves and by the satellite cells of the dorsal root ganglia (DRG). Recent studies have pointed out the importance of the molecules in the paracrine mechanisms related to neuronal maintenance and plasticity of lesioned motor and sensory peripheral neurons. Moreover, cultured Schwann cells have been employed experimentally in the treatment of central nervous system lesions, in special the spinal cord injury, a procedure that triggers an enhanced sensorymotor function. Those cells have been proposed to repair long gap nerve injury. METHODS: Here we used double labeling immunohistochemistry and Western blot to better characterize in vitro and in vivo the presence of the proteins in the Schwann cells and in the satellite cells of the DRG as well as their regulation in those cells after a crush of the rat sciatic nerve. RESULTS: FGF-2 and S100ß are present in the Schwann cells of the sciatic nerve and in the satellite cells of the DRG. S100ß positive satellite cells showed increased size of the axotomized DRG and possessed elevated amount of FGF-2 immunoreactivity. Reactive satellite cells with increased FGF-2 labeling formed a ring-like structure surrounding DRG neuronal cell bodies.Reactive S100ß positive Schwann cells of proximal stump of axotomized sciatic nerve also expressed higher amounts of FGF-2. CONCLUSION: Reactive peripheral glial cells synthesizing FGF-2 and S100ß may be important in wound repair and restorative events in the lesioned peripheral nerves.

OBJETIVO: O fator neurotrófico fator de crescimento de fibroblastos-2 (FGF-2, bFGF) e a proteína ligante de Ca++ S100ß são expressos pelas células de Schwann dos nervos e por células satélites do gânglio da raiz dorsal (GRD). Estudos recentes indicam a importância das moléculas nos mecanismos parácrinos relacionados à manutenção neuronal e à plasticidade de neurônios periféricos motores e sensoriais. Além disso, células de Schwann cultivadas têm sido empregadas experimentalmente no tratamento de lesões no sistema nervo central, especialmente na lesão da medula espinal, a qual mostrou uma melhora da função sensoriomotora. Estas células são ainda propostas no reparo do nervo lesado com perda de tecido. MÉTODOS: Usamos a dupla marcação imunohistoquímica e o Western blot para caracterizar melhor in vitro e in vivo a presença das proteínas nas células de Schwann e nas células satélites do GRD assim como sua regulação nessas células após a compressão do nervo ciático de ratos. RESULTADOS: FGF-2 e S100ß estão presentes nas células de Schwann do nervo ciático e nas células satélites do GRD. Células satélites do GRD axotomizado positivas para S100ß possuíam quantidade aumentada de imurreatividade da FGF-2. Células satélites reativas apresentando maior quantidade de FGF-2 formaram um anel ao redor dos corpos neuronais do GRD. Células de Schwann do coto proximal à axotomia do nervo ciático e positivas para S100ß também expressaram quantidades aumentadas de FGF-2. CONCLUSÃO: As células gliais periféricas ao sintetizar FGF-2 e S100ß podem ser importantes no reparo de cicatrização e em eventos restaurativos nas lesões do nervo.

Effects of systemic administration of ciliary neurotrophic factor on Bax and Bcl-2 proteins in the lumbar spinal cord of neonatal rats after sciatic nerve transection

Ciliary neurotrophic factor (CNTF) is a cytokine that plays a neuroprotective role in relation to axotomized motoneurons. We determined the effect of daily subcutaneous doses of CNTF (1.2 µg/g for 5 days; N = 13) or PBS (N = 13) on the levels of mRNA for Bcl-2 and Bax, as well as the expression and inter-association of Bcl-2 and Bax proteins, and the survival of motoneurons in the spinal cord lumbar enlargement of 2-day-old Wistar rats after sciatic nerve transection. Five days after transection, the effects were evaluated on histological and molecular levels using Nissl staining, immunoprecipitation, Western blot analysis, and reverse transcriptase-polymerase chain reaction. The motoneuron survival ratio, defined as the ratio between the number of motoneurons counted on the lesioned side vs those on the unlesioned side, was calculated. This ratio was 0.77 ± 0.02 for CNTF-treated rats vs 0.53 ± 0.02 for the PBS-treated controls (P < 0.001). Treatment with CNTF modified the level of mRNA, with the expression of Bax RNA decreasing 18 percent (with a consequent decrease in the level of Bax protein), while the expression of Bcl-2 RNA was increased 87 percent, although the level of Bcl-2 protein was unchanged. The amount of Bcl-2/Bax heterodimer increased 91 percent over that found in the PBS-treated controls. These data show, for the first time, that the neuroprotective effect of CNTF on neonatal rat axotomized motoneurons is associated with a reduction in free Bax, due to the inhibition of Bax expression, as well as increased Bcl-2/Bax heterodimerization. Thus, the neuroprotective action of the CNTF on axotomized motoneurons can be related to the inhibition of this apoptotic pathway.

EFFECTS OF NERVE INJURY ON THE EXPRESSION OF Trk RECEPTOR PROTEINS LOCALIZED ON THE TRIGEMINAL MESENCEPHALIC NEURONS / 神经解剖学杂志

Immunofluorescence histochemistry combined with retrograde tracing technique was employed to observe the effects of masseteric nerve transection on the expression of Trk ( tropomyosin-related kinase) receptor proteins, namely TrkA, TrkB and TrkC in the trigeminal mesencephalic nucleus ( Me5 ) of the rat. At 7 and 14 days following transection of masseteric nerve through which Fluorogold (FG) was applied to identify the Me5 neurons innervating masseter, brain sections were immunohistochemically processed to detect the three Trk isoforms in FG-labeled Me5 neurons. With the percentage of double-labeled neurons to the total number of FG-labeled neurons as the index,we demonstrated ( 1 ) a significant increase in the percentage of TrkA-immunoreactive (IR) Me5 neurons at both 7 and 14 days after nerve transection, (2) no significant, but gradual, increase in the percentage of TrkB-IR Me5 neruons with longer survival time post transection and ( 3 ) little change of TrkC expression. The current findings indicate that axotomy differently affected the expression of the individual Trk receptors and these expression patterns may reflect an adaptation of the Me5 neurons to the peripheral nerve injury.

Differential Activation of Microglia in the Substantia Nigra and Lesioned Site Following Medial Forebrain Bundle Transection / 대한해부학회지

Medial forebrain bundle (MFB) transmits the nigrostriatal dopaminergic (DA) axons, and previously we reported that transection of the MFB causes apotosis-like neurodegeneration of nigral DA neurons. On the other hand, it is likely to occur necrosis at the lesioned site where MFB is cut, due to direct mechanical transection of the brain tissue. To clarify the pathological dynamics of microglia reacting to the two different types of neuronal cell death, immunophenotypic and morphological features of microglia were compared and analyzed in the substantia nigra (SN) and lesioned site of the MFB axotomized rat brain. OX42 (mouse anti-rat CD 11b; pan-microglia marker), ED1 (mouse anti-rat lysosomal enzyme; phagocytic marker), and OX6 (mouse anti-rat MHC II) were used as primary antibodies for immunohistochemical localization of microglia, ED2 (mouse anti-rat macrophage) for macrophages, and anti-tyrosine hydro-xylase (TH) antibody for DA neurons. Quite numerous activated microglia with strong OX42 immunoreactivity were found in the SN at 1 day post-lesion (dpl), but most of them were ED1-and OX6-negative except only a few which were ED1-positive. This phenomenon was thought to be related with the stage of alert, the first step of microglial activation. It could be presumed that microglial phagocytosis may precede MHC II expression, because ED1-positive microglia appeared from 1 dpl while OX6-positive ones from 3 dpl. Number of activated microglia showing strong ED1, OX6 and OX42 immunoreactivity increased significantly by 7 ~14 dpl, and they specifically stick to various parts of dendrites and somas of TH-immunoreactive neurons of the SN. The phagocytic microglia of the SN maintained ramified form although they retained enlarged soma and shortened, thickened processes. The lesioned site was surrounded by numerous microglia showing strong OX42 and ED1 immunoreactivity as early as 1 dpl, indicating that microglial phagocytosis starts earlier in the lesioned site than in the SN. OX42-positive microglia of the lesioned site were ED2-negative, and showed amoeboid morphology already from 1 dpl. The amoeboid microglia became to be enlarged in their soma size by 3 dpl, and fused each other to form clumps within the necrotic zone by 5 ~7 dpl. The entire necrotic zone was completely filled with microglia of obscure outline with strong OX42 and ED1 immuno-reactivity. However, the majority of amoeboid microglia of the lesioned site were OX6-negative except a few. These results clearly demonstrate that activated microglia reacting to apoptotic neurodegeneration show different pathodynamic characteristics in terms of immunological phenotypes and morphology from those reacting to necrotic, mechanical lesion.

Neuroglial Proliferative Activity Following Medial Forebrain Bundle Axotomy / 대한해부학회지

Changes in morphology, immunophenotypes and proliferative activity of neuroglia are key features in most forms of CNS pathology. We compared proliferative activity of neuroglial cells in response to two different types of brain injury induced by medial forebrain bundle (MFB) axotomy. In the cannula track where acute necrosis occurs due to mechanical lesion caused by cannula inserted to incise the MFB, many BrdU-immunoreactive (ir) cells appeared around the cannula track already at 1 day post-lesion (1 dpl). Their number significantly increased by 7 dpl and then decreased, but considerable number of BrdU-ir cells was still found at 14 dpl. Some of the BrdU-ir cells were double-labeled with either OX-42 or GFAP. This finding suggests that both microglia and astrocytes are activated and proliferate immediately after the mechanical damage, and the proliferative activity is maintained in a considerable number of these cells by 14 dpl. In general, the main cell type showing BrdU immunoreactivity was amoeboid microglia within the necrotic zone immediately surrounding the cannula track, and was astrocytes in the periphery of the necrotic zone more or less apart from the cannula track. Previously, we reported that MFB axotomy induces apoptosis of dopaminergic (DA) neurons in the substantia nigra (SN). In the SN where axotomized DA neurons undergo apoptosis, only a few BrdU-ir cells were found at 1 dpl. Their number increased gradually from 3 dpl and peaked at 7 dpl, then significantly reduced at 14 dpl. Most of them were double-labeled with OX -42-positive ramified microglia but not with GFAP. This data indicates that microglia but not astrocyte are the cell type that proliferate in response to apoptotic neuronal cell death, and their morphology and proliferative activity are different from those observed in the cannula track. Meanwhile, in the both cannula track and SN, some BrdU-ir cells were thought to be neither GFAP-positive nor OX-42-positive, and thus they were presumed to be infiltrated peripheral immune cells. These results demonstrate that different types of neuronal cell death are accompanied with different neurogilal proliferative activities.

Pre-emptive Effect of Methylprednisolone on the Mechanical Allodynia Development after Peripheral Nerve Injuries in Rats / 대한마취과학회지

BACKGROUND: Glucocorticoids have anti-inflammatory effects and have been used to treat many types of nerve injury- associated chronic pain conditions. A randomized double-blind study was performed to determine if methylprednisolone could prevent the development of neuropathic pain after a peripheral nerve injury in rats. METHODS: Two groups of rats, one group (n = 50) injected intraperitoneally with methylprednisolone (100 mg/kg/day, for 7 days starting from 3 days prior to the nerve injury) and the other (n = 58) treated with saline with same manner, were compared in terms of the incidence and intensity of allodynia after a superior caudal trunk transection at the level between the 3rd and 4th sacral spinal nerves. The tail-flick responses to normally innocuous mechanical and thermal stimuli applied to the tail were observed as the behavioral signs of neuropathic pain. RESULTS: The proportions of rats exhibiting tail-flick responses to the mechanical (but not thermal) stimuli 7, 14 and 21 days after the nerve injury were significantly smaller in the methylprednisolone-treated group (2, 3 and 4 of 50 rats, respectively) than in the saline-treated, control group (11, 14 and 15 of 58 rats, respectively) (P = 0.009). However, the pain intensity was similar in mechanical allodynia developed rats of the two groups (P > 0.05), which was estimated based on the frequency and latency of the tail-flick responses after applying mechanical and thermal stimuli, respectively. CONCLUSIONS: These results suggest that a pre-emptive treatment with high methylprednisolone doses may be used to prevent the development of mechanical allodynia following peripheral nerve injuries.

EXOGENOUS FGF-2 REGULATES THE METABOLISM OF RAT FACIAL MOTONEURONS AFTER INJURY / 解剖学报

Objective To study the regulatory effect of exogenous fibroblast growth factor(FGF\|2) in expressions of calcitonin gene\|related peptide(CGRP) and FGF\|2 in facial motoneurons after injury. Methods The right facial nerve was transected 6?mm distal to the stylomastoid foraman.A 3?mm\+3 piece of Gelfoam presoaked in 25??l of various test solutions(normal saline,or 16?10 6?IU/L FGF\|2,or 32?10 6?IU/L FGF\|2) was implanted adjacent to the proximal nerve stump.After three days survival,the rats were killed and brainstems were removed.Serial 20??m cryosections were cut through the whole brainstem.The CGRP and FGF\|2 immunoreactivity were studied by immunohistochemisty and image analysis. Results An increase in the CGRP and decrease in the FGF\|2 signals were presented in axotomized motoneurons with saline\|treated animals.In FGF\|2\|treated animals,the lesion\|induced up\|regulation of CGRP and down\|regulation of FGF\|2 were attenuated compairing with normal saline treated animals.Conclusion\ Exogenous FGF\|2 can increase FGF\|2 expression and decrease CGRP expression in rat facial motoneurons after injury.\;[

Subdiaphragmatic vagotomy induces NADPH diaphorase in the rat dorsal motor nucleus of the vagus

Axotomy of the vagal motor neurons by cervical vagotomy induces NADPH diaphorase staining due to increased nitric oxide synthase expression in both the rat dorsal motor nucleus and nucleus ambiguous; furthermore, cerical vagotomy leads to cell death of the dorsal motor nucleus cells. Subdiaphragmatic vagotomy axotomizes the vagal motor cells further from the brainstem than cervical vagotomy, and cuts the fibers running only to the abdominal viscera. Here we report that subdiaphragmatic vagotomy is sufficient to induce NADPH diaphorase staining in the dorsal motor nucleus but does not induce staining in the nucleus ambiguus. Because the neurons of the dorsal motor nucleus do not undergo cell death after subdiaphragmatic vagotomy and are able to re-enervate the gut, the increased nitric oxide synthase expression after distal axotomy may be related more to regeneration than degeneration.

Retinal Neuronal Cell Death and Expression of p53p and Bax Protein Following Optic Nerve Axotomy

This investigation were performed in order to study the mechanism of neuronal cell degeneration and mediated gene of retinal cell death in optic nerve transection model. The optic nerve was transected at 5mm posterior from eye ball without affecting the retinal blood supply. Expression of cell deth gene were observed by p53p and Bax immunohistochemistry. The density of ganglion cels was determined by flat-mounted retinas after axotomy. Dying cells contained the pycnotic nuclei at 1 and 2 weeks and approximately 50% of ganglion cells were degenerated within 14 days after axotomy in ganglion cell layer. Bax and p53 were found to be expressed in the ganglion cell layer and inner unclear layer at 7 and 14 days after optic nerve transection. At 14 days, expression of death genes were observed strogly in ganglion cell layer and partially in inner unclear layer. this study suggest that p53p and Bax proteins may mediate ganglion cell degeneration after axotomy.

Changes of GDNF mRNA expression in proximal end and corresponding spinal cord after sciatic nerve sever in rats / 第二军医大学学报

Objective:To investigate the expression of GDNF mRNA on proximal end of sciatic nerve and T 12 L 1 spinal cord after sciatic nerve was cut in rats. Methods:The sciatic nerve of proximal end and spinal cord paralleling T 12 L 1 nerve root was taken respectively before and after sciatic nerve were severed. The level of GDNF mRNA on proximal end of sciatic nerve and spinal cord was observed and compared before and after sciatic nerve cut. Semi quantitative RT PCR method with ? actin as an inner consult was used to detect the expression of GDNF mRNA. Results:GDNF mRNA expression decreased by 10% 24 h after sciatic nerve was cut, 38% 7 d later, 45% 14 d and 52% 28 d in proximal end, while it decreased by 20%, 68%,80% and 85% on 1, 7, 14 and 28 d respectively in the spinal cord. Conclusion:The reduction of GDNF mRNA level on proximal end and homologous segmental spinal cord may be caused by losing the support of GDNF mRNA from the target tissue after sciatic nerve cut. This study provides a foundation for foreign GDNF to be used in treating SCI.

CHANGES OF STAT3 EXPRESSION IN RETINA AFTER TRANSECTION OF OPTIC NERVE / 解剖学报

Objective To study the expression and distribution of protein STAT3 in the retina after optic nerve transection. Methods Immunocytochemistry, Western blot and computer image analysis techniques were used. Results After optic nerve transection, STAT3 levels in the retina was highly up-regulated, the peak of which appeared at day 1 postaxotomy, then decreased gradually to the normal level 5 days later. More translocations of STAT3 to the nucleus were seen.Conclusion JAK-STAT signal transduction pathway was involved in the pathological processes in the retinal after transection of the optic nerve.

EFFECT OF DISTANCE OF AXOTOMY ON AXONAL REGENERATION OF RETINAL GANGLION CELLS INTO A NORMAL OR PRE-DEGENERATED PERIPHERAL NERVE GRAFT IN ADULT HAMSTERS / 解剖学报

Objective\ The present study was carried out to examine the relationship between the distance of axotomy and axonal regeneration systematically,and the effect of a pre\|degenerated peripheral nerve(PN) graft on axonal regeneration of retinal ganglion cells(RGCs) axotomized at different distances. Methods\ The optic nerve(ON) was transected at 0^5,1,1^5,2,3 or 7mm from the optic disc and a normal (the normal group) or pre\|degenerated(the pre\|degeneration group) PN graft was transplanted onto the ocular ON stump in adult hamsters. Results\ In both groups,the number of regenerating RGCs 28 days after grafting decreased significantly when the distance of axotomy increased from 0^5 to 7mm with a sharp decline between 0^5 and 3mm.When the corresponding distance points between the two groups were compared,enhanced regeneration was observed at 2 and 3mm in the pre\|degeneration group. Conclusion\ These results show that the distance of axotomy on the ON of adult hamsters is critical in determining the number of regenerating RGCs.The beneficial effect of a pre\|degenerated PN graft on axonal regeneration of axotomized RGCs is conditional on the distance of axotomy.\;