Objective To review the mechanism and effects of cell autophagy in the pathophysiology changes of peripheral nerve injury. Methods The recent literature about cell autophagy in peripheral nerve injury and regeneration was extensively reviewed and summarized. Results The researches through drugs intervention and gene knockout techniques have confirmed that the Schwann cell autophagy influences the myelin degeneration, debris clearance, inflammatory cells infiltration, and axon regeneration through JNK/c-Jun pathway. To adjust autophagy process could slow down the Wallerian degeneration, maintain the integrity of injured nerve, while the effect on axon regeneration is still controversial. Conclusion The Schwann cell autophagy plays a key role in the pathophysiology changes of peripheral nerve injury, the further study of its mechanism could provide new methods for the therapy of peripheral nerve injury.
Schwann cells (SC) play an important role in nerve regeneration. The cultures of both human and rabbit SC (gt;99%) were obtained, and were separately derived from the sciatic nerve of the human fetus and the rabbit respectively by "the method of reexplantation". In addition, the cryostore and resuscitation of SC were carried out, and the resuscitated cells could retain their growth properties.
OBJECTIVE: To investigate the effects of Ginsenoside Rb1 on the proliferation of Schwann cell cultured. METHODS: The sciatic nerve from SD rats was cultured in vitro; 10 micrograms/ml, 20 micrograms/ml, 200 micrograms/ml and 1 mg/ml Ginsenoside Rb1 was applied on the fifth day of culture. The proliferation of Schwann cells of sciatic nerves was determined in different time by MTT assay and thymidine incorporation assay. RESULTS: 10 micrograms/ml of Ginsenoside Rb1 significantly induced Schwann cell proliferation better than DMEM cell culture medium, but higher concentrations of Ginsenoside Rb1 at 1 mg/ml significantly inhibited the proliferation of Schwann cells, whereas 200 micrograms/ml of Ginsenoside Rb1 had similar effects to DMEM culture medium. CONCLUSION: Ginsenoside Rb1 at the optimal concentration is effective on inducing the proliferation of Schwann cells, but at higher concentration is cytotoxic for Schwann cells.
Objective To research the protective effects of different allogeneic cells injected into denervated muscles on ventricornual motor neuron. Methods Thirty-six adult female SD rats, weighting 120-150 g, were individed into four groups randomly and each group had nine. Left ischiadic nerves of all the SD rats, which were cut down on germfree conditions,were operated by primary suture of epineurium. Different cells were injected into the triceps muscles of calf in each group after operation with once a week for 4 weeks:1 ml Schwann cells (1×106/ml) in group A, 1 ml mixed cells ofSchwann cells and myoblast cells (1∶1,1×106/ml) in group B, 1 ml extract from the mixed cells of Schwann cells, myoblast cells and endotheliocytes (1∶1∶1,1×106/ml)in group C,and 1 ml culture medium without FCS as control group(group D). The observation of enzymohistochemistry and C-Jun expression in the ventricornual motor neuron was made after three months of operation. Results After 3 months of operation, the expressions of C-Jun in groups A, B and C were superiorto that in group D; the number of neuron was more than that of group D. The expressions of C-Jun in the ventricornual motor neuron were as follows: 128.591±0.766 in group A, 116.729±0.778 in group B, 100.071±2.017 in group C and 144.648±2.083 in group D; showing statistically significant difference between groupsA, B, C and D(P＜0.01). Enzymohistochemistry showed the well outlined and wellstacked cell body of neuron in groups A, B and C, and illdefined boundary of cytoplasm and nucleus. There was statistically significant defference in enzyme activity of the ventricornual motor neuron between groups(P＜0.01). Conclusion All of the Schwann cells,mixed cells of Schwann cells with myoblast cells,and the extract from Schwann cells, myoblast cells and endotheliocytes can protect the ventricornual motor neuron. And the protectiveeffect of the extract from Schwann cells, myoblast cells and endotheliocytes is superior to that of Schwann cells and mixed cells.
Objective To explore the advance in physical materials,chemical matrix, and biological seed cells for fabricating artificial nerve. Methods Recent literature relevant to artificial nerve, especially the achievement in physical material, chemical matrix and biological seed cells for fabricating artificial nerve, were extensively reviewed. Results Polymers of polylactic acid or polyglycolic acid and their polymer, polymer of hyaluronic acid and glut-aldehyde, polymer of polyacrylonitrile and polyvinylchloride were artificial nerve materials with the properties of good biocompatibility and biodegradation. A conduit with multichannel and high percentage of pores was beneficial to the regeneration of nerve. The activated Schwann cells were excellent seeds of artificial nerve. A suitable chemical matrix, such as laminin and alginate, could promote the regeneration of nerve. Conclusion The successful fabrication of artificial nerve lies in the advance in the mechanism of nerve regeneration and physical material, chemical matrix and biological seed cells.
Objective To study the migration of Schwann cells from the nerve autograft in the acellular nerve allograft of the rats in vivo. Mehtods The sciatic nerves (20 mm long) of the SD rats were harvested and prepared for the acellular nerve grafts by the chemical extraction. Then, they were observed by the gross view, HE staining, and Antilamininstaining, respectively. Another 32 female SD rats weighing 250-300 g were obtained for the study. A 2-mm-long nerve autograft was interposed between the two 10-mm-long nerve allografts to form a 22-mm-long composite. Then, the composite was placed in the muscle space, together with a sole 22-mm-long nerve allograftas a control. They were harvested at 5，10，15 and 20 days, respectively, and were then given the HE staining and the S-100 staining. Results The acellular nerve graft was semitransparent under the gross view. HE staining showed that no cell was observed within the nerve graft. Anti-laminin staining showed that the basal membrane was partially interrupted, with a positive result (dark brown). All the nerve grafts in both the groups exhibited the existenceof the cells. The S-100 positive cells were observed from the 15th day at the far ends of the two allografts of the composite; however, there were no suchcells observed within the sole nerve allograft. Conclusion Schwann cells from the sciatic nerves (2 mm- long) of the rats can migrate in the acellular nerve allograft to the far ends of the neighboring 10-mm-long nerve allografts at 15 days after operation, which offers the theoretical basis forthe repair of the longrange nerve defect by the composite of the acellular nerve allografts with the interposed nerve autograft.
OBJECTIVE: To review the advance in materials of nerve conduit and Schwann cell transplantation for preparation of artificial nerve with tissue engineering technique. METHODS: Recent literatures about artificial nerve, nerve conduit and Schwann cell transplantation were extensively reviewed. RESULTS: Many biomaterials such as silicon, dacron, expanded polytetrafluoroethylene(ePTFE), polyester and chitin could be used as nerve conduits to repair nerve defect, the degradable biomaterials were better. The nerve conduit with intrinsic filaments could be used to bridge an extended gap in peripheral nerve. Purified and cultured Schwann cells were still bioactive. Axonal regeneration could be enhanced after implantation of Schwann cells into nerve conduit. CONCLUSION: The ideal artificial nerve is composed of three dimensional biodegradable nerve conduit and bioactive Schwann cells, Schwann cells can be distributed in nerve conduit just like Bünger’s band.
Objective To evaluate the effect of Schwann cell (SC) on the proliferation of marrow mesenchymal stem cells (MSCs) and provide evidence for application of SC in construction of the tissue engineered vessels.Methods SC and MSCs were harvested from SD rats(weight 40 g). SC were verified immunohstochemically by the S-100 staining, and MSCs were verified by CD 44, CD 105, CD 34 and CD 45. The 3rd passages of both the cells were cocultured in the Transwell system and were amounted by the 3H-TDR integration technique at 1, 3, 5 and 7 days,respectively. The results were expressed by the CPM(counts per minute, CPM) values. However, MSCs on both the layers were served as the controls. The Westernblot was performed to assess the expression of the vascular endothelial growth factor (VEGF), its receptor Flk-1, and the associated receptor neuropilin 1(NRP-1) in SC, the trial cells, and the controls. Results SC had a spindle shape in the flasks, and more than 90% of SC had a positive reaction for the S-100 staining.MSCs expressed CD44 and CD105, and had a negativesignal in CD 34 and CD 45. The CPM values of MSCs in the trial groups were 2 411.00±270.84，3 016.17±241.57，6 570.83±2 848.27 and 6 375.8±1 431.28at 1, 3, 5 and 7 days, respectively. They were significantly higher in their values than the control group (2 142.17±531.63，2 603.33±389.64，2 707.50±328.55，2 389.00±908.01), especially at 5 days （P＜0.05）. The Western blot indicated that VEGF was expressedobviously in both the SC group and the cocultured MSCs grou,p and was less visible in the control cells. The expressions of Flk-1 and NRP-1 inthe cocultured MSCs were much ber than in the controls. Conclusion SC can significantly promote the proliferation of MSCs when they are cocultured. The peak time of the proliferation effect appeared at 5 days. This effect may be triggered by the up-regulation of VEGF in MSCs, which also leads to the upregulation of Flk-1 and NRP-1 .
Objective To study the result of using nerve conduit coated with chitin and filled with a guide-fiber to repair peripheral nerve defect. Methods Twenty-four female adult SD rats were made the model of 14 mm-gap on bilateral sciatic nerve under sterile condition. The rats were randomly divided into 4 groups(n=6),group A: polymer polyglycolic-lactic acid(PGLA) nerve conduit coated with chitin and filled with a guide-fiber as experimental group to repair 14 mm gap of rat sciatic nerve；group B: PGLA nerve conduit coated with chitin； group C: PGLA nerve conduit； group D: autograft (control group). The repair result was evaluated by normal observation, EMG testing and S-100 histological immunostaining analysis 4 and 12 weeks after operation.Results Four weeks after the operation，there were new regenerated immature fibers in groups A,B and C, 12 weeks after the operation, the regenerated nerve fibers were seen to have bridged the gap. There were myelinated fibers equably distributed and rarely newgenerated nerve fibers in distal parts of group D. The repair result of PGLA nerve conduit coated with a chitin and filled with guide-fiber was better than that of groups B and C（Plt;0.05）. There was significant difference of nerve fiber diameter，thickness of myelin sheath and fiber density in group D from those in groups A, B and C（Plt;0.05），but there were degenerative changes such as vacuoles insheaths and myelin separation in proximal and few new regenerated nerve fibers in distal parts of group D. Conclusion PGLA nerve conduit coated with chitin and filled with a guide-fiber offers a possible substitute for the repair of peripheral nerve defect.
Objective To review the research progress on the role of Schwann cells in regulating bone regeneration. MethodsThe domestic and foreign literature about the behavior of Schwann cells related to bone regeneration, multiple tissue repair ability, nutritional effects of their neurotrophic factor network, and their application in bone tissue engineering was extensively reviewed. ResultsAs a critical part of the peripheral nervous system, Schwann cells regulate the expression level of various neurotrophic factors and growth factors through the paracrine effect, and participates in the tissue regeneration and differentiation process of non-neural tissues such as blood vessels and bone, reflecting the nutritional effect of neural-vascular-bone integration. ConclusionTaking full advantage of the multipotent differentiation ability of Schwann cells in nerve, blood vessel, and bone tissue regeneration may provide novel insights for clinical application of tissue engineered bone.