The Protective Effects Of The Acellular Nerve Matrix Grafts On The Cells Of Spinal Anterior Horns And Spinal Ganglia

ObjectiveRecently, peripheral nerves were acellularly treated and the grafts of extracellular nerve matrix were prepared by the principle and the method of tissue engineering science. The peripheral nervous injury was repaired by the graft, which obtained the good effects promoting the regeneration and functional repair of the injured nervous fibers. However, what effects do the grafts have on the neurons giving off associated nervous fibers (including the neurons of spinal anterior horns and spinal ganglia) ? There are still no reports about it. This study will explore this program.MethodThirty Wistar rats were used. Ten rats were prepared the acellular grafts of sciatic nerves by chemical extraction; the other twenty rats were divided into the experimental group and the control group (the injured sciatic nerve group) and each group had ten rats. The grafts, L7 - S2 spinal cord and corresponding spinal ganglia were taken out three to four months after the rats were fed. All the samples were stained by HE and Nissl and were prepared to samples of electronic microscopy, which were observed by histology and ultrastructure. The neuron number of spinal anterior horns and spinal ganglia was analyzed by statistics.ResultsIf the approaches preparing the grafts of the acellular peripheral nervousmatrix by chemical extraction were applied in room temperature, they could be shortened seven to ten days. The experimental group ( nervous injury was bridged by acellular graft) was observed after operation. The paws of some operated rats suffered from swelling and ulcer and recovered normally after three to four weeks. After three months, the operated leg stepped backward powerfully, walked normally gradually and escaped when the bottom of the operated paws was punctured by a needle. The operated paw;s of the control group have suffered from swelling and ulcer for a long time and the motor and sense functions haven \ recovered. The operated leg of the control group( nerve defect) havent recovered in the functions of motor and sense. Three or four months after operation, a large quantity of regenerated nervous libers were observed in HE staining transverse and vertical slices of the grafts in the experimental group; the regenerated axon, myelin and schwann cells were observed clearly in the samples of electronic microscopy. The spinal anterior cells of L7 - S2 were seen on HE and Nissl staining samples in the normal aspect of the experimental group and the control group. The cells were quite large, which were divided into the medial group and the lateral group, and there were rich speckle Nissl bodies in cytoplasm. The structures of the spinal anterior cells in L7 - S2 were normal in the graft of the experimental group and the defect of the control group, but the groups were not clear, and there were hyperplastic glial cells. The number of the anterior cells innervating limb muscles decreased, especially the control group. The results of statistics showed that there was a significant difference in the number of the spinal anterior cells between the transplanted aspect(10. 37 ± 1.45 ) and the normal aspect( 14.40 ± 1. 81) of the experimental group, as well as the transplanted aspect(5. 97 ± 1. 69) of the experimental group and the defect aspect of the control group( P <0.01 ,Tab. 1).The spinal ganglia of L7 - S2 were seen on HE and Nissl staining samples in the normal aspect of the experimental group and the control group. The shape and the structures of the cells were normal, and minute granulated Nissl bodies were full of the cytoplasm, which were comprised by large, middle and little cells. The structures of the ganglion ceDs in L7 - S2 were normal in the transplanted aspect of the experimental group and the defected aspect of the controlgroup, but the number of the cells was less lhan the normal aspect, obviously the control group. The results of statistics showed that there was a significant difference in the number of the ganglion cells between the transplanted aspect (45.57 ±5. 88) and the normal aspect (53. 57 ±6. 57) of the experimental group, as well as transplanted aspect of the experimental group and the defect aspect(36.90±5. 15) of the control group(P <0.01 ,Tab.2).ConclusionsThe grafts of acellular peripheral nervous matrix were prepared in asepsis and room temperature, which could be shortened the time and could be applied for emergency. The experiment indicated that the immunity of the grafts disappeared essentially, which possessed good histocompatibility and effectively induced and promoted the regeneration of the injured nerve. The experiment first proved that the grafts had great protective effects on the spinal anterior cells and spinal ganglia giving off spinal nerves.