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BACKGROUND:We have previously prepared acellular nerve graft and implanted bone marrow mesenchymal stem cells into the graft, to successful y construct tissue engineered artificial nerves. OBJECTIVE:Horseradish peroxidase nerve retrograde tracer technique was used to evaluate protective effects on sensory neurons fol owing sciatic nerve defect bridging with tissue engineered artificial nerves constructed by acellular nerve graft and bone marrow mesenchymal stem cells in rats. METHODS:Adult, clean, healthy, male Sprague-Dawley rats were randomly assigned to three group:(1) Experimental group:Rat sciatic nerve detect was bridged by acellular nerve graft combined with bone marrow mesenchymal stem cells;(2) Blank control group:Rat sciatic nerve defect was bridged by acellular nerve graft;(3) Autologous nerve control group:Rat sciatic nerve defect was bridged by autologous nerve transplantation. Regeneration of sensory neurons in the spinal dorsal root ganglia was assessed using horseradish peroxidase nerve retrograde tracer technique at 12 weeks fol owing surgery. RESULTS AND CONCLUSION:Sensory neuron regeneration in the spinal dorsal root ganglia at 12 weeks fol owing surgery was better in the experimental group compared with blank control group. No significant difference was detected between experimental group and autologous nerve control group. S-100 immunohistochemical staining in plantar skin showed brown positive reaction in each group. These findings indicate that tissue engineered artificial nerves constructed by acellular nerve graft and bone marrow mesenchymal stem cells have protective effects on sensory neurons in the spinal dorsal root ganglia, and can promote the recovery of sensory function and repair sciatic nerve defect in rats.
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BACKGROUND: Tissue-engineered artificial nerve was successfully constructed with the compound of acellular nerve graft and bone marrow mesenchymal stem cells, suggesting that it could promote peripheral neural regeneration.OBJECTIVE: To construct tissue-engineered artificial nerve, and to verify neural functional recovery of bridging rats following sciatic nerve defect.METHODS: A total of 60 adult male SD rats were used to induce sciatic nerve defect models (15 mm in length), and they were then randomly divided into three groups, with 20 rats in each group. Sciatic nerve defect group was treated with tissue-engineered artificial nerve; blank control group was treated with tissue-engineered nerve stent; autoallergic neural control group was treated with autoallergic neural transplantation. Twelve weeks after bridging, histology of sciatic nerve and neuralfunctional recovery were detected via gross observation, wet mass of tibialis anterior muscle, and histological analysis.RESULTS AND CONCLUSION: At 12 weeks after bridging surgery, rats in experimental group were able to stand on the floor,and withdrawal reflex was detected at plantar skin on the surgical side. S-100 protein of plantar skin was positive. There was no significant difference in wet mass of tibialis anterior muscle between experimental and autoallergic neural transplantation group (P ＞ 0.05). HRP retrograde tracing in the experimental group demonstrated that HRP-positive cells were observed in both spinalcord and posterior root ganglion. There was no significant difference in number of myetinated nerve fiber, thickness of myelin sheath, and area of nerve tissue between experimental and autoallergic neural transplantation group. The results demonstrated that the compound of acellular nerve graft and bone marrow mesenchymal stem cells could successfully construct tissue-engineered artificial nerve to repair sciatic nerve defect and promote neurohistological reconstruction and functional recovery.
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BACKGROUND: Previous studies have successfully prepared the natural and biologically degraded acellular nerve graft and have proved the effect of promoting neural regeneration.OBJECTIVE: To construct tissue engineered artificial nerve with acellular nerve graft and bone marrow mesenchymal stem cells, and to observe the effect of promoting motor functional recovery and repairing rat sciatic nerve defects. DESIGN, TIME AND SETTING: Randomized control animal experiment was performed in the Medical TIssue Engineering Laboratory of the First Affiliated Hospital of Liaoning Medical University between June 2008 and February 2009. MATERIALS: Wistar adult healthy male rats weighing 180-200 g were used to prepare acellular nerve graft, while Wistar adult healthy male rats weighing 100-120 g were used to prepare bone marrow mesenchymal stem cells. Tissue engineered artificial nerve was produced with acellular nerve graft co-cultured with bone marrow mesenchymal stem cells. METHODS: Sixty Wistar adult healthy male rats weighing 180-200 g were induced sciatic nerve defect models, 15 mm long. SD rats were divided into three groups at random with 20 animals in each group. ①Experiment group: Rat sciatic nerve defects were bridged with tissue engineered artificial nerve. ②Blank control group: Rat sciatic nerve defects were bridged with tissue engineered nerve scaffold. ③Autologous nerve control group: Rat sciatic nerve defects were bridged with autologous nerve graft. MAIN OUTCOME MEASURES: At 12 weeks postoperation, the recovery of motor function was evaluated with gross observation, electrophysiology, histological observation and triceps surae wet weight.RESULTS: ①At 12 weeks postoperation, the toes at the operation side could separate and supported to the ground in the experiment group; there was no significant difference in the regenerated nerve conduction velocity between experimental group and autologous nerve graft group. ②At 12 weeks postoperation, histochemical stain results showed AchE-positive motor end-plate arranged regulady in the middle and superior part of gestrocnemius muscle to form end-plate zone in the experiment group. By use of silver staining, the regenerated nerve tract and the emergent branch were shown to be connected with motor end-plate.③There was no significant difference in the tibialis anterior muscle wet weight between experimental group and autologous nerve graft group. CONCLUSION: Bridging acellular nerve graft and bone marrow mesenchymal stem cells into rat sciatic nerve defects can promote motor functional recovery.
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Objective To observe the repairing effect of the acellular nerve allografts on the sciatic nerve gap of rat. Methods The acellular nerve allografts,treated by hypotonic-chemical detergent,were put on the 10 mm gap of the sciatic nerve in the rat.The action potential of the regenerated nerves was determined by the electrophysiologic method 13 weeks after operation.The morphology of the regenerated nerves was observed under light microscope and electron microscope,and the results were analyzed statistically. Results No inflammation and rejected reaction were found in the period of 13 weeks after operation in the operated and control groups.There was no significant difference in number of the regenerated nerve fibers,diameter of the axons,and the thickness of the regenerated myelinated nerve between the experimental group and control group.Conclusion The present results indicated that the acellular nerve allografts had good biocompatibility for the host rat in vivo and might as a bridge promote the regeneration of the injured sciatic nerve.;
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Objective The experiment was designed to investigate the effect of acellular nerve allografts on the functional recovery and reconstruction of the nerve-muscle structure of the sciatic nerve defect in rats. Methods Acellular nerve allograft was transferred into the defected rat sciatic nerve with 10mm long.The wet weight of tibialis anterior was weighed at 12 and 24 weeks postoperatively compared with control group.The conducted velocity of regenerated nerve and the effect of regenerated nerve on tibialis anterior were investigated by electrophysiologic test,and silver staining combined with AChE histochemical methods were used in the experiment separately. Results The wet weight of tibialis anterior and the conducted velocity of regenerated nerve in experimental group were similar to those in control group in 12 and 24 weeks after transplantation.The positive acetylcholinesterase(AChE)histochemical reaction was observed in the tibialis anterior at 12 weeks with deeper staining and located in the middle of tibialis anterior tidily at 24 weeks after operation.The regenerated nerve bundles and nerve terminals were found to grow into the motor end-plate of the tibialis anterior in silver staining combined with AChE staining in experiment group.Electromyogram showed that the regenerated nerve has innervated tibialis anterior already.Conclusion The results indicated that extracted nerve allografts as a bridge can promote the motor functional recovery and reconstruction of the nerve-muscle structure of the defected rat sciatic nerve.