Effect of Long-term Peripheral Nerve Stimulation on Neuro-Muscular Complex Morphologic Recovery in Experiment / Efecto de la Estimulación del Nervio Periférico a Largo Plazo sobre la Recuperación Morfológica del Complejo Neuromuscular en Experimento

SUMMARY: Peripheral nerve injury is an extremely important medical and socio-economic problem. It is far from a solution, despite on rapid development of technologies. To study the effect of long-term electrical stimulation of peripheral nerves, we used a domestically produced electrical stimulation system, which is approved for clinical use. The study was performed on 28 rabbits. Control of regeneration was carried out after 3 month with morphologic techniques. The use of long-term electrostimulation technology leads to an improvement in the results of the recovery of the nerve trunk after an injury, both directly at the site of damage, when stimulation begins in the early period, and indirectly, after the nerve fibers reach the effector muscle.

La lesión de los nervios periféricos es un problema médico y socioeconómico extremadamente importante. Sin embargo, y a pesar del rápido desarrollo de las tecnologías, aún no tiene solución. Para estudiar el efecto de la estimulación eléctrica a largo plazo de los nervios periféricos, utilizamos un sistema de estimulación eléctrica de producción nacional, que está aprobado para uso clínico. El estudio se realizó en 28 conejos. El control de la regeneración se realizó a los 3 meses con técnicas morfológicas. El uso de tecnología de electro estimulación a largo plazo conduce a una mejora en los resultados de la recuperación del tronco nervioso después de una lesión, tanto directamente en el lugar del daño, cuando la estimulación comienza en el período temprano, como indirectamente, después de que las fibras nerviosas alcanzan el músculo efector.

Clinical analysis of chronic mild occupational carbon disulfide poisoning / 中国职业医学

Objective: To analyze clinical features and electroneuromyography (ENMG) results of chronic mild occupational carbon disulfide poisoning cases. Methods: A total of 344 patients diagnosed with chronic mild occupational carbon disulfide poisoning based on GBZ 4-2002 Diagnostic Criteria of Occupational Chronic Carbon Disulfide Poisoning were selected as study subjects from 2006 to 2019 using the retrospective study method. Their clinical data was collected and analyzed. Results: The main symptoms of the study subjects were dizziness, headache, insomnia, dreaming, memory impairment, numbness and weakness in the distal extremities. Positive signs mainly included symmetrical glove and stocking distribution like sensory disorders in the distal extremities, and the weakening or absent Achilles tendon reflex and knee reflex. The incidence of symptoms and signs increased with the length of service (all P<0.01). The incidence of fundus and venous changes in patients was 41.3%, which increased with the length of service (P<0.01). ENMG examination showed varying degrees of abnormalities in the peripheral motor and/or sensory nerves in all patients, with a higher incidence of motor nerve abnormalities than sensory nerve abnormalities (21.1% vs 3.7%, P<0.01). The incidence of motor nerve abnormality was higher on the right side than the left side (23.7% vs 18.5%, P<0.01). The incidences of motor nerve abnormalities from high to low in the order were median nerve, common peroneal nerve, ulnar nerve and posterior tibial nerve (34.9% vs 27.9% vs 16.6% vs 5.1%, P<0.01). The incidences of sensory nerve abnormalities from high to low in the order were median nerve, ulnar nerve and sural nerve (5.2% vs 5.1% vs 0.7%, P<0.01). The incidences of left ulnar nerve, right ulnar nerve and right median nerve were higher in male patients than in female patients (15.2% vs 5.3%, 24.0% vs 11.7%, 44.8% vs 28.7%, all P<0.05), while the incidences of the left and right common peroneal nerve in lower extremity motor nerve were lower in male patients than in female patients (18.4% vs 52.1%, 21.2% vs 46.8%, all P<0.01). Conclusion: Chronic mild occupational carbon disulfide poisoning was mainly manifested as multiple peripheral nerve injury. ENMG results showed that the distal motor nerve conduction abnormalities were more sensitive than the sensory nerve conduction abnormalities, with a higher degree of impairment in the upper limb than the lower limb, and more impairment in the right side than the left side.

Effect of folic acid coated-crosslinked urethane-doped polyester elastomer nerve conduit on promoting the repair of long distance peripheral nerve injury in rats / 中国修复重建外科杂志

OBJECTIVE@#To investigate the effect of folic acid coated-crosslinked urethane-doped polyester elastomer (fCUPE) nerve conduit in repairing long distance peripheral nerve injury.@*METHODS@#Thirty-six 3-month-old male Sprague Dawley rats weighing 180-220 g were randomly assigned to 3 groups, each consisting of 12 rats: CUPE nerve conduit transplantation group (group A), fCUPE nerve conduit transplantation group (group B), and autologous nerve transplantation group (group C), the contralateral healthy limb of group C served as the control group (group D). A 20-mm-long sciatic nerve defect model was established in rats, and corresponding materials were used to repair the nerve defect according to the group. The sciatic function index (SFI) of groups A-C was calculated using the Bain formula at 1, 2, and 3 months after operation. The nerve conduction velocity (NCV) of the affected side in groups A-D was assessed using neuroelectrophysiological techniques. At 3 months after operation, the regenerated nerve tissue was collected from groups A-C for S-100 immunohistochemical staining and Schwann cell count in groups A and B to compare the level of nerve repair and regeneration in each group.@*RESULTS@#At 3 months after operation, the nerve conduits in all groups partially degraded. There was no significant adhesion between the nerve and the conduit and the surrounding tissues, the conduit was well connected with the distal and proximal nerves, and the nerve-like tissues in the conduit could be observed when the nerve conduit stents were cut off. SFI in group A was significantly higher than that in group C at each time point after operation and was significantly higher than that in group B at 2 and 3 months after operation ( P<0.05). There was no significant difference in SFI between groups B and C at each time point after operation ( P>0.05). NCV in group A was significantly slower than that in the other 3 groups at each time point after operation ( P<0.05). The NCV of groups B and C were slower than that of group D, but the difference was significant only at 1 month after operation ( P<0.05). There was no significant difference between groups B and C at each time point after operation ( P>0.05). Immunohistochemical staining showed that the nerve tissue of group A had an abnormal cavo-like structure, light tissue staining, and many non-Schwann cells. In group B, a large quantity of normal neural structures was observed, the staining was deeper than that in group A, and the distribution of dedifferentiated Schwann cells was obvious. In group C, the nerve bundles were arranged neatly, and the tissue staining was the deepest. The number of Schwann cells in group B was (727.50±57.60) cells/mm 2, which was significantly more than that in group A [(298.33±153.12) cells/mm 2] ( t=6.139, P<0.001).@*CONCLUSION@#The fCUPE nerve conduit is effective in repairing long-distance sciatic nerve defects and is comparable to autologous nerve grafts. It has the potential to be used as a substitute material for peripheral nerve defect transplantation.

Pinostrobin from Boesenbergia rotunda attenuates oxidative stress and promotes functional recovery in rat model of sciatic nerve crush injury

Oxidative stress plays a role in the delay of peripheral nerve regeneration after injury. The accumulation of free radicals results in nerve tissue damage and dorsal root ganglion (DRG) neuronal death. Pinostrobin (PB) is one of the bioflavonoids from Boesenbergia rotunda and has been reported to possess antioxidant capacity and numerous pharmacological activities. Therefore, this study aimed to investigate the effects of PB on peripheral nerve regeneration after injury. Male Wistar rats were randomly divided into 5 groups including control, sham, sciatic nerve crush injury (SNC), SNC + 20 mg/kg PB, and SNC + 40 mg/kg PB. Nerve functional recovery was observed every 7 days. At the end of the study, the sciatic nerve and the DRG were collected for histological and biochemical analyses. PB treatment at doses of 20 and 40 mg/kg reduced oxidative stress by up-regulating endogenous glutathione. The reduced oxidative stress in PB-treated rats resulted in increased axon diameters, greater number of DRG neurons, and p-ERK1/2 expression in addition to faster functional recovery within 4 weeks compared to untreated SNC rats. The results indicated that PB diminished the oxidative stress-induced nerve injury. These effects should be considered in the treatment of peripheral nerve injury.

Study on the mechanism of Taohong siwu decoction improving peripheral nerve injury induced by paclitaxel in rats / 中国药房

OBJECTIVE To explore the mechanism of Taohong siwu decoction （THD） improving peripheral nerve injury induced by paclitaxel （PTX） in rats. METHODS The effects of THD （1 g/mL drug-containing serum） and PTX （0.1 μmol/L） alone or in combination on the proliferation rate of Schwann cells line RSC96 as well as the expressions of lysosomal-associated membrane protein-2 （LAMP2）， autophagy marker protein yeast Atg 6 homolog （Beclin1）， phosphatidylinositol 3-kinase （PI3K）， protein kinase B （Akt）， and mammalian target of rapamycin （mTOR） were investigated， and then compared with autophagy promoter rapamycin and autophagy inhibitor 3-methyladenine （3-MA）. The effects of high-dose and low-dose THD on the expressions of myelin basic protein （MBP） and myelin protein zero （MPZ）， S100 calcium-binding protein （S100）， LAMP2， Beclin1， PI3K， Akt and mTOR were tested at the end of the experiment. RESULTS After treatment of THD+PTX， the proliferation rate of RSC96 cells was significantly higher than those treated with PTX alone. After treatment of THD+PTX or THD+ 3-MA， the protein expressions of LAMP2 and Beclin1 in RSC96 cells were significantly higher than those treated with PTX or 3- MA alone， while the protein expressions of PI3K， Akt and mTOR were significantly lower than those treated with PTX or 3-MA alone （P＜0.05）. Compared with model group， the protein expressions of MBP， MPZ， S100， LAMP2 and Beclin1 in sciatic nerve of rats were increased significantly in THD high-dose and low-dose groups， while the protein expressions of PI3K， Akt and mTOR were significantly decreased （P＜0.05）. CONCLUSIONS THD may activate Schwann cell autophagy by inhibiting the PI3K/Akt/ mTOR signaling pathway， thereby improving peripheral nerve injury caused by PTX.

Fotobiomodulação com LED induz melhora na funcionalidade da marcha em ratos após lesão nervosa periférica / Photobiomodulation with LED increased the gait functionality in rats submitted to peripheral nerve injury

Introdução: As lesões nervosas periféricas (LNP) podem resultar em distúrbios motores e sensoriais alterando a funcionalidade do membro afetado, porém pouco se conhece a respeito dos efeitos da fotobiomodulação (FBM) com diodo emissor de luz (LED). Objetivo: Analisar os efeitos do LED sobre a funcionalidade da marcha de ratos Wistar pós LNP. Metodologia: Ratos Wistar foram submetidos a LNP por esmagamento de ciático e analisados nos seguintes grupos experimentais: (1) Controle; (2) LNP; (3) LNP+ LED (780 nm, potência média 40 mW, exposição radiante, energia por ponto, 3,2 J sobre o nervo ciático (LEDn); (4) LNP+ LED em nervo e região do músculo envolvido (LEDnm) e (5) LNP+ LED apenas em região do músculo (LEDm). Após 7, 14, 21 e 28 dias foram realizadas as análises de marcha utilizando o Índice Funcional Ciático (IFC). Resultado: Após 7 dias, os grupos tratados com LED apresentaram uma melhora da marcha em relação ao grupo Lesão, sendo essa melhora mais pronunciada no grupo LEDn. Após 14 dias, os grupos LEDn e LEDnm apresentaram valores semelhantes ao grupo controle e após 21 e 28 dias o IFC não apresentou diferenças entre os grupos experimentais. Conclusão: O LED aumentou a funcionalidade da marcha avaliada pelo IFC após 1 e 2 semanas pós LNP, especialmente quando foi usado na região nervosa associada ou não à região muscular.

Introduction: Peripheral nerve injuries (PNI) can result in motor and sensory disturbances altering the functionality of the affected limb, however not much is known about the effects of photobiomodulation (PBM) with light emitting diode (LED). Objective: We aimed to analyze the effects of LED on the gait function of Wistar rats after PNI. Methodology: Wistar rats were submitted to PNI by sciatic crush and analyzed in the following experimental groups: (1) Control; (2) PNI; (3) PNI+ LED (780 nm, mean power 40 mW, radiant exposure, energy per spot, 3.2 J on the sciatic nerve) (LEDn); (4) LNP+ LED on nerve and involved muscle region (LEDnm) and (5) LNP+ LED only on muscle region (LEDm). After 7-, 14-, 21- and 28-days gait analyses were performed using the Sciatic Functional Index (SFI). Results: After 7 days, the groups treated with LED showed an improvement in gait compared to the PNI group, with this improvement being more pronounced in the LEDn group. After 14 days, the LEDn and LEDnm groups showed similar values to the control group and after 21 and 28 days the SFI did not show differences between the experimental groups. Conclusion: LED increased the gait functionality evaluated by SFI after 1 and 2 weeks post-PNI, especially when it was used in the nerve region associated or not with the muscle region.

Adipose-derived stem cell transplantation for the treatment of peripheral nerve injury induced by 1-bromopropane in rats / 中国职业医学

@#Abstract: Methods - （ ） To investigate the repairing effect of adipose derived stem cells ADSCs transplantation in - - Methods 1 bromopropane induced peripheral nerve injury in rats. A total of 45 specific pathogen free male SD rats were （ ） （ ） randomly assigned to the control group 15 rats and exposure group 30 rats . The rats in the exposure group were gavaged with - ， ， 1 bromopropane at a dose of 800 mg/kg body weight while the control group were given with equal volume of corn oil once a ， - day five days per week for eight weeks. The rat model of peripheral nerve injury induced by 1 bromopropane was established - ， - and was randomly assigned to the self recovery group and ADSCs group 12 rats in each group. ADSCs group and self recovery （ 6 ） ， group were injected with 0.5 mL contains 1×10 cells ADSCs or 0.5 mL phosphate buffer solution respectively by tail vein once a week for four weeks. The control group was not administered any treatment. The rats in each group were assessed using - - （ ） ， ， inclined plane test and Basso Beattie Bresnahan BBB score on the first day before treatment as well as 7 14 21 and 28 day ， after treatment. At the end of treatment the sciatic nerve was isolated for histopathological examination. The oxidative stress - indexes in the cerebral motor cortex were detected by colorimetric analysis. The levels of brain derived neurotrophic factor （ ） （ ） - Results BDNF and nerve growth factor NGF in the sciatic nerve were detected by enzyme linked immunosorbent assay. The - maximum tilt angle of the inclined plate and the BBB score were lower in self recovery group at the five time points of treatment （ P< ） all 0.05 compared with the control group. The maximum tilt angle of the inclined plate test was higher in ADSCs group at 21 （ P< ）， ， ， （ P< ）， and 28 days of treatment all 0.05 and the BBB score was higher at 7 14 21 and 28 days of treatment all 0.05 - （ ） when compared with the self recovery group. The level of malondialdehyde MDA in the cerebral motor cortex increased （P< ）， （ ） （ ） （ P< ）， 0.05 while the superoxide dismutase SOD activity and glutathione GSH level decreased all 0.05 and the levels （ P< ） - of BDNF and NGF in the sciatic nerve decreased all 0.05 in self recovery group compared with the control group. There was ， ， no significant difference in SOD activity and MDA GSH BDNF and NGF levels between ADSCs group and control group （ P> ） （P< ）， （ all 0.05 . The level of MDA in cerebral motor cortex decreased 0.05 the SOD activity and GSH level increased all P< ）， （P< ） - 0.05 and the level of BDNF in sciatic nerve increased 0.05 in ADSCs group compared with the self recovery group. Conclusion - - ADSCs transplantation can repair peripheral nerve injury induced by 1 bromopropane via anti oxidative stress and regulating the secretion of neurotrophic factors.

Transcriptome Analysis of Schwann Cells at Various Stages of Myelination Implicates Chromatin Regulator Sin3A in Control of Myelination Identity / 神经科学通报·英文版

Enhancing remyelination after injury is of utmost importance for optimizing the recovery of nerve function. While the formation of myelin by Schwann cells (SCs) is critical for the function of the peripheral nervous system, the temporal dynamics and regulatory mechanisms that control the progress of the SC lineage through myelination require further elucidation. Here, using in vitro co-culture models, gene expression profiling of laser capture-microdissected SCs at various stages of myelination, and multilevel bioinformatic analysis, we demonstrated that SCs exhibit three distinct transcriptional characteristics during myelination: the immature, promyelinating, and myelinating states. We showed that suppressor interacting 3a (Sin3A) and 16 other transcription factors and chromatin regulators play important roles in the progress of myelination. Sin3A knockdown in the sciatic nerve or specifically in SCs reduced or delayed the myelination of regenerating axons in a rat crushed sciatic nerve model, while overexpression of Sin3A greatly promoted the remyelination of axons. Further, in vitro experiments revealed that Sin3A silencing inhibited SC migration and differentiation at the promyelination stage and promoted SC proliferation at the immature stage. In addition, SC differentiation and maturation may be regulated by the Sin3A/histone deacetylase2 (HDAC2) complex functionally cooperating with Sox10, as demonstrated by rescue assays. Together, these results complement the recent genome and proteome analyses of SCs during peripheral nerve myelin formation. The results also reveal a key role of Sin3A-dependent chromatin organization in promoting myelinogenic programs and SC differentiation to control peripheral myelination and repair. These findings may inform new treatments for enhancing remyelination and nerve regeneration.

Research progress in promotion of peripheral nerve regeneration by regulating macrophages / 中华显微外科杂志

This article reviews the research progress in promotion of peripheral nerve regeneration by regulating macrophages, a new idea for the research and treatment of peripheral nerve injury. The Trauma Center of The First People's Hospital Affiliated to Shanghai Jiao Tong University reviewed the relevant literatures in the regulation of macrophages on peripheral nerve regeneration at home and abroad, from 2013 to 2021, were reviewed and analysed. Of the study from 2013 to 2021, autologous nerve transfer was the main option in the treatment of peripheral nerve injury, but it has many setbacks such as insufficient donor, new nerve injury and local neuroma. Modulating macrophage-related function can effectively improve the prognosis of nerve injury. In recent years, the regulation of macrophages in the treatment of nerve injury is mainly through the mechanism of M1 macrophages polarisation to M2 macrophages, increase of phagocytosis, change of the phenotype of macrophages, and so on. By studying the characteristics of macrophages and regulating the function and phenotype of macrophages, it would provide a new idea and important research direction in the treatment of peripheral nerve injury.

Two-dimensional and three-dimensional techniques for determining the kinematic patterns for hindlimb obstacle avoidance during sheep locomotion / Técnicas bidimensionais e tridimensionais para determinar os padrões cinemáticos durante a ultrapassagem de obstáculos pelos membros pélvicosdurante a locomoção de ovinos

ABSTRACT: Analysis of locomotion is often used as a measure for impairment and recovery following experimental peripheral nerve injury. Compared to rodents, sheep offer several advantages for studying peripheral nerve regeneration. In the present study, we compared for the first time, two-dimensional (2D) and three-dimensional (3D) hindlimb kinematics during obstacle avoidance in the ovine model. This study obtained kinematic data to serve as a template for an objective assessment of the ankle joint motion in future studies of common peroneal nerve (CP) injury and repair in the ovine model. The strategy used by the sheep to bring the hindlimb over a moderately high obstacle, set to 10% of its hindlimb length, was pronounced knee, ankle and metatarsophalangeal flexion when approaching and clearing the obstacle. Despite the overall time course kinematic patterns about the hip, knee, ankle, and metatarsophalangeal were identical, we found significant differences between values of the 2D and 3D joint angular motion. Our results showed that the most apparent changes that occurred during the gait cycle were for the ankle (2D-measured STANCEmax: 157±2.4 degrees vs. 3D-measured STANCEmax: 151±1.2 degrees; P<.05) and metatarsophalangeal joints (2D-measured STANCEmin: 151±2.2 degrees vs. 3D-measured STANCEmin: 162 ± 2.2 degrees; P<.01 and 2D-measured TO: 163±4.9 degrees vs. 3D-measured TO: 177±1.4 degrees; P<.05), whereas the hip and knee joints were much less affected. Data and techniques described here are useful for an objective assessment of altered gait after CP injury and repairin an ovine model.

RESUMO: A análise da locomoção é frequentemente usada como uma medida para avaliar a disfunção e sua recuperação após lesão nervosa periférica experimental. Quando comparadas com os roedores, as ovelhas oferecem várias características atrativas como modelo experimental para o estudo da regeneração nervosa periférica. Não existem estudos acerca dos resultados da locomoção após lesão e reparação do nervo periférico no modelo ovino. No presente estudo, realizámos e comparámos a cinemática bidimensional (2D) e, pela primeira vez, tridimensional (3D) do membro pélvico durante a ultrapassagem de obstáculos no modelo ovino. Este estudo teve como objetivo obter dados cinemáticos para servir de modelo para uma avaliação objetiva do movimento articular do tornozelo em estudos futuros de lesão e reparação do nervo fibular comum (FC) no modelo ovino. A estratégia usada pelas ovelhas para elevar o membro pélvico sobre um obstáculo com uma altura moderada, fixado em 10% do seu comprimento, caracteriza-se por uma flexão pronunciada do joelho, tornozelo e metatarso-falangeana ao se aproximar e ultrapassar o obstáculo. Apesar dos padrões cinemáticos do quadril, joelho, tornozelo e metatarso-falangeano terem sido idênticos, foram encontradas diferenças significativas entre os valores do movimento angular das articulações em 2D e 3D. Os nossos resultados mostram que as mudanças mais aparentes que ocorreram durante o ciclo da marcha foram nas articulações do tornozelo (em 2DSTANCEmax: 157±2.4 graus vs. em 3D STANCEmax: 151±1.2 graus; P<.05) e metatarso-falangeana (em 2D STANCEmin: 151±2.2 graus vs. em 3D STANCEmin: 162 ± 2.2 graus; P<.01 e em 2D TO: 163±4.9 graus vs. em 3D TO: 177±1.4 graus; P<.05), enquanto as articulações do quadril e do joelho foram muito menos afetadas. É provável que os dados e técnicas descritas aqui sejam úteis para uma avaliação objetiva das alterações na marcha após lesão e reparação do PC no modelo ovino.

Important roles of non-coding RNA in peripheral nerve repair / 中国组织工程研究

BACKGROUND: Non-coding RNA is widely distributed in the nervous system in vivo and a significant change in the expression of non-coding RNA has been observed in a neural injury model. This suggests that non-coding RNA may serve as a potential target for resolving the challenges of peripheral nerve repair. OBJECTIVE: To summarize the mechanisms of microRNA, circular RNA and long non-coding RNA in the process of repair after peripheral nerve injury with the attempt to determine the possible treatment of peripheral nerve injury. METHODS: The first author retrieved the relevant literatures in CNKI and PubMed databases published from January 2001 to April 2019. The key words were “non-coding RNA, miRNA, circRNA, IncRNA, peripheral nerve injury” in Chinese and English, respectively. Forty-three literatures were included in accordance with the exclusion and inclusion criteria. RESULTS AND CONCLUSION: (1) MicroRNAs can act on certain signal pathways, regulate the apoptosis, growth, proliferation and differentiation of Schwann cells and participate in the repair of peripheral nerve injury. (2) Circular RNAs act as microRNA sponges to competitively inhibit the transcription in microRNA, and exert corresponding biological functions. (3) A large amount of long non-coding RNAs are expressed after peripheral nerve injury, and play a key role in the peripheral nerve regeneration.

Signal pathways related to regeneration after peripheral nerve injury / 药学实践杂志

Due to the limited self-repair ability of neurons after injury, there has been a lack of effective treatments for nerve injury in clinical practice. So, to find drugs that promote the repair after nerve injury has become a research hotspot. Schwann cells and neurons play an important role in regeneration of the peripheral nerves after injury. This review summarizes the classification of peripheral nerve injury, the signaling pathways related to peripheral nerve regeneration in Schwann cells and neurons as well as diseases related to peripheral nerve injury, and provides a basis for further exploration of the regeneration mechanism after peripheral nerve injury.

Research progress on dental pulp stem cells in the repair of peripheral nerve injury / 口腔疾病防治

@#Peripheral nerve injury (PNI) is a common disease in the oral cavity that can easily lead to loss of function and abnormal appearance. The application of dental pulp stem cells (DPSCs) combined with tissue engineering in the repair of PNI is a research hotspot. DPSCs have the advantages of abundant sources, simple extraction, low immunogenicity and a high proliferation rate in vitro. They can differentiate into Schwann cells (SCs). SCs can induce autophagy and secrete key neurotrophic factors, such as nerve growth factor, brain-derived neurotrophic factor, ciliary neurotrophic factor and glial cell-derived neurotrophic factor. SCs are beneficial for the repair of nerve injury. DPSCs in different periods have differences in immune regulation, anti-inflammatory effects, expression of neural markers, angiogenesis and so on, which provide more diversified choices for nerve repair. At present, the introduction of tissue engineering provides a more controllable and improved microenvironment for DPSCs, which is conducive to the application and development of DPSCs in regenerative medicine and tissue engineering. However, there are still many problems to be solved, such as the selection of stem cells, functional link recovery, uncontrollable direction of axon regeneration, regulation of the peripheral nervous system and mechanism of repair.

3-methyladenine improves the efficiency of sciatic nerve allograft in mice / 中国组织工程研究

BACKGROUND: Recent studies have shown that the occurrence of Wallerian degeneration is closely related to autophagy in Schwann cells. The regulation of autophagy in Schwann cells can significantly affect the occurrence and development of Wallerian degeneration, subsequently altering axon regeneration and myelination. OBJECTIVE: To clarify whether sciatic nerve allograft can achieve higher efficiency when the cell autophagy is inhibited by 3-methyladenine. METHODS: We harvested 16 sciatic nerve segments from 8 female C57BL/6J mice that were purchased from Beijing Vital River Laboratory Animal Technology Co., Ltd. in China. All the segments were equally divided into experimental and control groups and cultured in 3-methyladenine culture medium and normal culture medium for 72 hours, respectively. Another 16 female C57BL/6J mice were taken to make animal models of left sciatic nerve defects. After modeling, the sciatic nerve segments were grafted to repair sciatic nerve defect through microsurgery: 3-methyladenine-treated nerve segments in the experimental group and normally treated nerve segments in the control group. Sciatic nerve index in each mouse was recorded at 2, 4, 6, and 8 weeks after modeling. At 8 weeks after modeling, the regenerated nerve segments were histologically analyzed using hematoxylin-eosin staining, immunofluorescent staining, toluidine blue staining, and transmission electron. The animal experiment was approved by the Animal Ethics Committee of Peking Union Medical College. RESULTS AND CONCLUSION: There were no differences in the sciatic nerve index between the two groups (P > 0.05) except at 8 weeks after modeling (P < 0.05). Hematoxylin-eosin staining revealed an intact nerve structure in the experimental group but a large area of voids in the control group. Immunofluorescent staining indicated that there were nerve tracts with more complete structures in the experimental group than the control group. Toluidine blue staining revealed some myelinated and unmyelinated nerve fibers regenerated in the experimental group and only a few of myelinated nerve fibers and unmyelinated axons newly formed in the control group. Under the transmission electron microscope, myelin sheath thickness and myelinated fiber diameter were significantly higher in the experimental group than the control group (P < 0.05). Therefore, 3-methyladenine-treated nerve allografts could inhibit autophagy in Schwann cells, maintain the myelin sheath structure of the allograft, and promote axonal regeneration and functional recovery.

Establishment and evaluation of traumatic neuroma model / 中国组织工程研究

BACKGROUND: Traumatic neuroma is a common complication of peripheral nerve injury, and basic research on peripheral nerve repair and regeneration through a traumatic neuroma model is rarely reported. OBJECTIVE: To establish and identify a traumatic neuroma model. METHODS: The study was approved by the Laboratory Animal Ethical Committee of Chinese PLA General Hospital. Fifteen healthy Sprague-Dawley rats aged 8 weeks old were selected to expose the sciatic nerve under microscope, and the sciatic nerve was cut 1 cm away from the posterior gluteal muscle branch using microscissors. The proximal nerve was sutured to the surrounding muscle with 11-0 microlines, and the distal nerve was left open and reflexed. After 3 weeks, ultrasonic and histological examinations were used to verify the formation of neuroma. RESULTS AND CONCLUSION: (1) Ultrasound: After 3 weeks of modeling, the proximal nerve showed obvious spindle enlargement, which was a hypoechoic parenchymal nodule without echo. (2) Gross observation: The proximal nerves were enlarged and slightly stiffened, with fibrous connective tissue hyperplasia and adhesion to the surrounding tissues. (3) Hematoxylin-eosin staining indicated hyperplasia of fibrous tissue and disorderly growth of nerve fibers in the tumor. Immunofluorescence staining (S100, NF200) revealed irregular hyperplasia of Schwann cells and nerve axons in the tumor. (4) These results suggest that the model of traumatic neuroma is successfully constructed.

Ultrasound-guided platelet-rich plasma injection for repair of sciatic nerve crush injury / 中国组织工程研究

BACKGROUND: Platelet-rich plasma (PRP) contains growth factors that affect tendon, ligament, muscle and bone healing. On this basis, researchers gradually realize that such molecules released after PRP activation can regulate the early inflammation of peripheral nerve injury, activate Schwann cells, promote the polarization of macrophages, and actively prevent the hyperplasia of collagen fibers, thus becoming the key drivers of nerve function recovery. OBJECTIVE: To evaluate the value of ultrasound-guided PRP injection in the repair of sciatic nerve crush injury. METHODS: Twenty-eight healthy New Zealand white rabbits (provided by the Beijing Longan Experimental Animal Breeding Center) were randomly divided into normal group, control group, single PRP group and multiple PRPs group. In the normal group, the right sciatic nerve was exposed and then sutured directly. In the control group, a compression injury model of the right sciatic nerve was established. In the single PRP group, autologous PRP was injected around the injured nerve under ultrasound guidance at 24 hours after modeling. In the multiple PRPs group, autologous PRP was injected around the injured nerve under ultrasound guidance at 24 hours after modeling, and then the PRP injection was performed once at the 3rd and 5th weeks after modeling. Histological and morphological observation of regenerated nerves, wet weight recovery and histological manifestations of the denervated muscle were evaluated at 12 weeks after modeling. The study protocol was approved by the Administrative Committee of Experimental Animals in PLA General Hospital with the approval No. 2015-x10-02. RESULTS AND CONCLUSION: The integral optical density values of NF-200 and S100 staining, myelinated nerve fiber density, myelinated nerve fiber diameter and myelin sheath thickness were significantly increased in the single PRP and multiple PRPs groups compared with the control group (all P < 0.05), and the multiple PRPs group showed better outcomes than the single PRP group (all P < 0.05), but was still inferior to the normal group (all P < 0.05). Compared with the control group, wet weight and cross-sectional area of muscle fibers significantly increased in the single PRP group and multiple PRPs group (P < 0.05), and the multiple RPRs group showed better outcomes than the single PRP group, but was still inferior to the normal group (P < 0.05). To conclude, ultrasound-guided multi-frequency injection of autologous PRP has a good effect on the repair of sciatic nerve crush injury.

Transplantation of bone marrow mesenchymal stem cells for denervated muscular atrophy / 中国组织工程研究

BACKGROUND: Microscopic surgery or some adjuvant treatments can neither effectively delay nor treat denervated muscle atrophy by repairing damaged nerve cells. Studies have found that bone marrow mesenchymal stem cells have the potential for directional differentiation and repair damaged tissues under certain environmental factors. It is speculated that the cells can play a certain role in repairing denervated atrophic muscles. OBJECTIVE: To investigate whether transplantation of bone marrow mesenchymal stem cells can alleviate and retard atrophy of denervated muscles. METHODS: Primary bone marrow mesenchymal stem cells were isolated from Sprague-Dawley rats, and passage 3 cells were labeled by BrdU for cell transplantation. Thirty Sprague-Dawley rats were divided into three groups, 10 rats in each group. In the sham operation group, only the main trunk of the sciatic nerve was exposed but not clamped. In the treatment group, the main trunk of the sciatic nerve was clamped and bone marrow mesenchymal stem cell suspension was injected into the gastrocnemius muscle. In the control group, after the sciatic nerve trunk was clamped, the gastrocnemius muscle innervated by the sciatic nerve was injected with DMEM medium of equal volume (without cells and fetal bovine serum). Basso, Beattie and Bresnahan scores were used to evaluate the motor function of the rat’s left hindlimb at 1 and 2 weeks after cell transplantation. Changes in the gastrocnemius muscle fibers were observed by hematoxylin-eosin staining and BrdU immunohistochemical staining at 14 days after cell transplantation. RESULTS AND CONCLUSION: The passage 3 bone marrow mesenchymal stem cells were positive for BrdU. The labeled cells could survive in and repair the denervated muscle tissue in the treatment group. Compared with the model group, the denervated muscle fibers of the treatment group recovered from mutual fusion and re-arranged regularly. To conclude, transplantation of bone marrow mesenchymal stem cells can alleviate and retard atrophy of denervated muscles.

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 Endogenous Neurotrophic Factors on Nerve Regeneration after Cryopreserved Sciatic Nerve Allograft in Rats / 中国康复理论与实践

Objective:To investigate the effect of endogenous neurotrophic factor (ENTFs) on nerve regeneration after cryopreserved sciatic nerve allograft in rats. Methods:The 15-mm sciatic nerves from female Sprague-Dawley rats were placed in DMEM solution and pretreated in vitro for 1 day, 3 days, 7 days, 14 days, and 21 days at 37 ℃ with 5% CO2 (groups A, B, C, D and E) respectively. Fresh nerve group (group F) was set up. The protein expression of glial cell line-derived neurotrophic factor (GDNF), nerve growth factor (NGF), Bcl-2, Bax, Caspase-3, major histocompatibility complex (MHC)-I and MHC-II was detected by Western blotting. The above six groups were cryopreserved in liquid nitrogen for four weeks. The living cells and dead cells of the nerves after cryopreservation were observed by Calcein-AM/propidium iodide staining. In addition, the above six cryopreserved groups and another fresh nerve group (group G) were transplanted to the Wistar rats by allografting (groups A', B', C', D', E', F' and G'). Isograft group (group H') was set up. One week after transplantation, the expression of CD8+ T cells and macrophages of the graft were observed by immunofluorescence staining, and the plasma levels of interleukin (IL)-2, interferon (IFN)-γ, and tumor necrosis factor (TNF)-α were detected by ELISA. Twenty weeks after transplantation, the compound muscle action potential (CMAP) and nerve conduction velocity (NCV) were examined by electrophysiology. The wet weight ratio of gastrocnemius muscle was calculated by the operational side compared with the contralateral side. The expression of neurofilament protein (NF) 200 of the transplanted nerves was observed by immunofluorescence staining. The number of myelinated nerve fibers was analyzed by toluidine blue staining. The thickness of myelinated was analyzed by electron microscopy. Results:Compared with group F, the protein expression of GDNF and NGF increased in groups C, D and E (P < 0.05); the protein expression of Bcl-2 reduced and the protein expression of Bax and Caspase-3 increased in groups B, C, D, and E (P < 0.05); the protein expression of MHC-I and MHC-II decreased in all the pretreated groups (P < 0.05). Four weeks after cryopreservation, compared with groups F and G, the number of living cells decreased in groups C, D and E. One week after transplantation, compared with groups F' and G', the expression of CD8+ T cells and macrophages decreased, and the plasma concentration of IL-2 and TNF-α decreased in groups C', D' and E' (P<0.05). Twenty weeks after transplantation, CMAP, NCV, the wet weight ratio of gastrocnemius muscle, the number of axon and thickness of myelin sheath were better in groups C', D' and E' than in groups F' and G' (P<0.05), as well as the expression of NF200. Conclusion:ENTFs can be induced by pretreating the sciatic nerve in vitro. Cryopreserved sciatic nerve with high expression of ENTFs could promote nerve regeneration and functional recovery after allograft.

Advances of Wnt Signaling Pathway in Osteoporosis after Peripheral Nerve Injuries (review) / 中国康复理论与实践

Wnt signaling pathway plays an important role in bone metabolism. Wnt signaling pathway inhibitors are mediated by the mechanical load, while nerve growth factors and neuropeptide (neuropeptide substance P and neuropeptide Y), which are closely related to the peripheral nervous system, affect bone metabolism through the Wnt signaling pathway. This paper reviewed the mechanism of Wnt signaling pathway in osteoporosis after peripheral nerve injury from these two aspects.