慢性卡压对大鼠坐骨神经影响的实验研究

目的　探讨慢性卡压对大鼠坐骨神经功能和组织形态学的影响。方法　采用Mackinnon设计的大鼠坐骨神经慢性卡压模型 ,选用SD雄性大鼠制造慢性卡压模型 32只 ,作为卡压组 ;同样手术方法但硅胶管不卡压而取出者 16只 ,作为空白对照组 ;另选 8只不手术 ,作为正常组。空白组和卡压组每周测一次坐骨神经功能指数(SFI) ;空白对照组在造模后 2、4周 ;卡压组在造模后 2、4、6、8周 ;正常组在第 2周分别测定运动神经传导速度(MNCV) ,并取坐骨神经 (卡压组取卡压段神经 )进行组织学观察。结果　第 4周空白对照组的SFI、MNCV已与正常组差异无显著性 (P >0 0 5 ) ,但卡压组和空白对照组及正常组差异均有显著性 (P <0 0 5 )。组织学观察 :神经卡压后髓鞘先受累 ,首先表现为形态改变 ,之后厚薄变化 ,最后轴索受累 ,第 4周时出现脱髓鞘改变。结论　Mackinnon设计的大鼠坐骨神经慢性卡压模型中存在着牵拉因素对神经的损伤 ;神经慢性卡压的组织学变化规律为髓鞘先受累 ,首先表现为形态改变 ,之后厚薄变化 ,最后轴索受累 ,第 4周时出现脱髓鞘改变

Experimental Reseach of Effects of Chronic Compression on the Rat Sciatic Nerve

Objective To investigate the effect of chronic compression on the rat sciatic nerve's function and histomorphology. Methods According to the rat model of sciatic nerve compression designed by Mackinnon, the thirty two Sprague Dawley male rats were made the model of sciatic nerve compression as compression group; sixteen rats had the same operation but the silitube was took out as blank control group ;another 8 rats without operation as normal group. Sciatic Function Index(SFI) was determined in both blank control group and compression group every week.At the 2nd,4th week,2nd,4th,6th,8 th week and 2nd week,motor nerve conduction velocity(MNCV) was detected in blank control group,compression group and normal group respectively, with the sciatic nerve(for compression group, the compressed nerve)taken out to perform histomorphology analysis.Results At the 4th week, SFI and MNCV of blank control group had no significant difference to that of normal group( P >0 05),but that of compression group had significant difference to that of blank control group and normal group( P <0 05).Myelin sheath was first affected after compression.The changes of its morphology appeared,then follwed by changes of the thickness,at last the axon was affected. Demylination appeared at the 4th week. Conclusions The rat sciatic nerve compression model designed by Mackinnon had the strain injury to the nerve.And the compressed nerve showed histological changes of myelin sheath and axon.