BACKGROUND: Auto-neural transplantation is used widely on peripheral neurological defect, but it also has some difficulties. So some scholars try to use xenoma-neural transplantation; however, it is hard todeal with immunological rejection.OBJECTIVE: To study the effect of transforming growth factor-β1 (TGFβ1) used in local area on neural regeneration after transplantation of fresh nerve allograft.DESIGN: Randomized controlled study.SETTING: Hand Surgery Department of Union Hospital Affiliated to Tongji Medical College of Huazhong University of Science and TechnologY.MATERIALS: The experiment was conducted in the Union Hospital Affiliated to Tongji Medical College of Huazhong University of Science and Technology between August 2001 and October 2002. Totally 60healthy adult Wistar rats from different confinements were randomly divided into three groups including experimental group, blank group and rncontrol group with 20 in each group.METHODS: TGF-β1 plasmid was prepared for using. Establishment of animal model: Sciatic nerve at the 0.5 cm deep of piriformis muscle of rats in the two groups was cut with disinfectant razor into chip regularly about 2.0 cm. The excisional nerve segment was exchanged to transplant plerosis neurological defect. TGF-31 was injected into the local muscles and bisection of nerve in the experimental group, and equal volume of saline was injected into rats in the blank group and the control group. In addition, rats in the experimental group and the blank group were not treated with any drugs, but cyclosporine A (15 mg/kg) was used to feed rats in the control rngroup. Ten rats from each group were taken for section and staining at the 6th and the 12th week: ① Glees-luxot fast blue staining method; ② myelin sheath fast blue staining method. Axonal amount: Fields were randomly taken from the middle staining samples 12 weeks later and 1.0 mm2 interaxis-cylinder was counted under light microscope of 400 times. Comparisons among groups were analyzed with i test.MAIN OUTCOME MEASURES: Morphological observation and axonal amount of transplanted area in each group.RESULTS: Quantitative analysis of the experimental animals: Totally 60rats entered the final analysis without any loss. ① Infiltration of monocytes was observed widely in various areas of graft in the blank group;meanwhile, desiccation of myelin sheath and plenty of vacuolations were also observed, especially at the sixth week. The whole graft was infiltrated rnby monocyte with severe rejection. Few axis-cylinders were regenerated in the transplanted segment. At the 12th week, graft was slender, plenty of scar tissues were proliferated, edema was observed obviously, few Schwann cells and regenerated axis-cylinders were observed, and lots of regenerated axis-cylinders did not pass the whole graft. A few infiltrative monocytes were observed, and edema was observed obviously, but new vessel was formed in transplanted nerve, and regenerated axis-cylinders passed the whole graft in the experimental group and the control group.Lots of Schwann cells were observed at the 6th week; meanwhile, regenerated axis-cylinders passed the whole graft at the 12th week, a quantitative myelinization was formed, Schwann cells proliferated obviously, and edema between axis-cylinder was relieved. Numbers of peripherally regenerrnated axis-cylinder of nerve and remyelination in each ransplanted area were more than those in the central area, and edema between peripheral axis-cylinder was milder than that in the central area in the experimental group. ② Twelve weeks after operation, 5 rats in each group were selected to observe their fields, which were taken randomly from neural graft,under the microscope of 400 times to count 1.0 mm2 inter-axis-cylinders.Number of axis-cylinder was higher in the experimental group and the control group than that in the blank group, and the differences were significant [(78.3±4.6), (76.1±4.2) , (15.0±3.5) ,t=3.056, t=2.948, P ＜ 0.01];however, number in the experimental group was similar to that in the control group, and differences were not significant [(78.3±4.6), (76.1±4.2),t=1.982 P ＞ 0.05].CONCLUSION: TGF-β1 used in local area plays an immunosuppressive action locally, decreases host immunological rejection, increases the number of axis-cylinder, and accelerates growth of nerve.%背景:周围神经缺损多采用自体神经移植,但存在一些问题,许多学者尝试异体神经移植,但存在许多问题,免疫排斥反应就是其中之一.目的:观察局部应用转化生长因子β1对新鲜同种异体神经移植后神经再生的影响.设计:随机对照的实验.单位:华中科技大学同济医学院附属协和医院手外科.材料:实验于2001-08/2002-10在华中科技大学同济医学院附属协和医院完成.选择健康成年不同窝的Wistar大鼠60只,随机分为实验组、空白组、对照组3组,每组20只.方法:制备转化生长因子β1质粒待用.制备动物模型,将两组大鼠的坐骨神经在梨状肌孔下0.5 cm处,用消毒的剃须刀片整齐切断并切除2.0 cm,切除的神经段互换移植修复神经缺损,实验组局部肌肉及神经两断端注射转化生长因子β1质粒,空白组、对照组注射等量的生理盐水,实验组、空白组不使用任何药物,对照组给予环孢霉素A(15 mg/kg)喂养.分别于6周和12周各取10只取材、切片、染色染色:①Gleesluxotfast blue法染色.②髓鞘坚牢蓝染色法.轴索计数:术后12周的移植体中段染色标本,随机取视野,在光镜400倍下计算1.0mm2内轴索数.组间比较采用t检验.主要观察指标:各组移植区形态学观察和轴突计数.结果:实验动物数量分析:60只动物在实验过程中无死亡,全部进入结果分析.①空白组可见移植物的不同地方出现广泛的单核细胞浸润,髓鞘脱水,可见大量的空泡变性,以6周时最为明显,整个移植物均被单核细胞浸润,排异反应严重,在移植段中,有极少量的轴突再生.12周时,移植体变细,大量瘢痕组织增生,水肿明显,可见极少量的许旺氏细胞和再生轴突,绝大多数再生的轴突未通过整个移至段.实验组、对照组有少量的单核细胞浸润,水肿较明显,但可见新生的血管在移植神经中形成,再生的轴突通过移植体.6周时,可见较多的许旺氏细胞增生.12周时,再生轴突已通过移植体,有一定量的髓鞘形成,许旺氏细胞增生明显,轴索间水肿减轻.各组移植段中外周的神经再生的轴突数量和髓鞘再生的数量较中心的多,且实验组中外周的轴索间水肿较中心的明显减轻.②术后12周,每组各取5只大鼠,在神经移植体中段随机取视野,400倍显微镜下观察计算1.0 mm2内轴突数,实验组、对照组轴突数显著高于空白组,组间差异有极显著性[(78.3±4.6),(76.1±4.2),(15.0±3.5),t=3.056,t=2.948,P＜0.01].实验组和对照组接近,差异无显著性[(78.3±4.6),(76.1±4.2),t=1.982 P＞0.05].结论:局部使用转化生长因子β1质粒,可在局部发挥免疫抑制作用,降低宿主的免疫排斥反应.并使移植体轴突数增多,促进神经生长.
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