Objective To observe the histomorphology and the biocompatibil ity of acellular nerve prepared by different methods, to provide the experimental evidence for the selection of preparation of acellular nerve scaffold. Methods Forty-eight adult Sprague Dawley rats, male or female, weighing 180-220 g, were selected. The sciatic nerves were obtained from 30 rats and were divided into groups A, B, and C (each group had 20 nerves). The acellular sciatic nerves were prepared by the chemical methods of Dumont (group A), Sondell (group B), and Haase (group C). The effect to remove cells was estimated by the degree of decellularization, degree of demyel ination, and intergrity of nerve fiber tube. The histocompatibil ity was observed by subcutaneous implant test in another 18 rats. Three points were selected along both sides of centre l ine on the back of rats, and the points were randomly divided into groups A1, B1, and C1; the acellular nerve of groups A, B, and C were implanted in the corresponding groups A1, B1, and C1. At 1, 2, and 4 weeks after operation, the rats were sacrificed to perform the general observation and histological observation. Results The histomorphology: apart of cells and the dissolved scraps of axon could be seen in acellular never in the group A, and part of Schwann cell basilar membrane was broken. In group B, the cells in the acellular never were not removed completely, the Schwann cell basilar membrane formed bigger irregular hollows, part of the Schwann cell basilar membrane was broken obviously. But in the group C, the cells were completely removed, the Schwann cell basilar membrane remained intactly. Group C was better than group A and group B in the degree of decellularization, degree of demyel ination, integrity of nerve fiber tube and total score, showing significant differences (P lt; 0.05). The subcutaneous implant test: there were neutrophils and lymphocytes around the acellular nerve in 3 groups at 1 week after implant. A few of lymphocytes were observed around the acellular nerve in 3 groups at 2 weeks after implant. The inflammation was less in groups A1, B1, and C1 at 4 weeks after implant, part of the cells grew into the acellular nerve and arranged along the Schwann cell basilar membrane. The reaction indexes of the inflammational cells in group A1 and group B1 were higher than that in group C1 at 1, 2, and 4 weeks after implant, showing significant differences (P lt; 0.01), but there was no significant difference between group A1 and group B1 (P gt; 0.05). Conclusion The acellular sciatic nerves prepared by Haase method has better acellular effect and the histocompatibil ity than those by the methods of Dumont and Sondell.
Objective To assess the sensory restoration after the greater auricular nerve is implanted into the flap to repair the buccal defect in rabbits. Methods Fifteen Japanese white rabbits, weighing 2.0-2.5 kg, were randomly divided into the experimental group (nerve implanted), the control group (nerve unimplanted), and the normal group (without any treatment). In the experimental and the control group, circular defects (2.0 cm×2.0 cm) were constructed in the left cheek of the rabbits. Then, the cervicalflaps (4.5 cm×2.5 cm) were transferred and the great auricular nerve was implanted into the defects in the experimental group, and the flaps without any nervewere implanted into the defects in the control group. The subjects in the normal group were given no treatment. After 6 months, the nerve discharge, the HE staining, and the immunohistochemical method were used to assess the regeneration of the nerve fibers. Results The nerve discharge and the percentage of the different kinds of the nerve fibers in the experimental group (124.2±33.8 roots) were not statistically different from those in the normal group （138.4±20.4 roots，Pgt;0.05）, but significantly different from those in the control group（18.8±5.6 roots,Plt;0.05）. In the center of the flap in the experimental group, the receptive field of the nerve fibers was identical to theimplanting approach of the greater auricular nerve. The HE staining and the immunohistochemical staining showed that the density of the regenerated fibers in the center of the flap in the experimental group reached the normal level.There was no regenerated fibers in the control group. Conclusion The great auricular nerve implanted into the cervical flaps has a good effect on reconstruction of the buccal defect in rabbits.
Objective To study the effect of motor nerve implantation after ectopic transplantation of skeletal muscle on nerve regeneration in rat. Methods Sixty Sprague-Dewley male 8 monthold rats were randomly divided into 3 groups: control group,in situ implantation group and ectopic transplantation group. In control group, obturator nerve controlling right gracilis was cut off. In in situ implantation group, the right gracilis was cut off and replanted to its original site, and the obturator nerve was implanted to the muscle. In ectopic transplantation group, the right gracilis was cut off and transplanted to the muscle of the left leg, and the obturator nerve was implanted to the muscle. After 25 weeks, the neurophysiological information was collected through electromyography and the weight of the muscle was measured. Results The potentialwithout control of the nerve existed in control group. There were no significant differences in latency, amplitude and conduct velocity betweenin situ implantation group and ectopic transplantation group(Pgt;0.05).The atrophy of gracilis was dominant incontrol group, the weight of the muscle was 158.0±19.3 mg. The weights of the muscle were 509.6±14.5 mg in ectopic transplantation group and 516.8±12.7 mg in in situ mplantation group, showing no significant difference (P＞0.05). The weights of the muscle in in situ implantation and ectopic transplantation group were larger than that in control group, showing significant difference(P＜0.05). Conclusion Motor nerve implantation after ectopic transplantation of skeletal muscle could prevent the atrophy of the muscle and resume partial function of nerve.
This article reported the implantation of the greater auricular nerve into the cervicoshoulder skin flap in rabbits. The progress following implantation of the nerve was continuously observed. According to the time elapsed from the nervesbeing implanted, the experimental animals were divided into 4 groups, 4 animalsin each group, in the order of 1, 2, 4 and 6 months groups, respectively, and the normal skin and the cervicoshoulder skin flaps without nerve implantation were used as control. The electron microscope was the method used to observed theprogress. The results showed that in the 2nd month the unmyelinated fibers first appeared, then the myelinated in the 4th month. The caliber of the axons, the thickness of the myelin sheath and the ratio of MF/UF increased with time. In the 4th month, the number of the regenerating nerve fibers (unmyelinated fibers predominant) had achieved the highest level and significantly exceeded that of thenormal skin. But at the 6 months. the MF/UF ratio was still for lower than normal.