胫神经和腓总神经损伤修复后相应脊髓节段神经元细胞Bcl-2、Bax蛋白表达差异的实验研究

摘要

目的 比较大鼠下肢同一平面胫神经、腓总神经损伤修复后相应脊髓节段神经元细胞Bcl-2、Bax蛋白表达差异.方法 雄性SD大鼠90只随机分为3组: A组为对照组, B组为胫神经切断缝合组, C组为腓总神经切断缝合组.分别于术后1、3、7、14、28 d取大鼠L4~6节段脊髓进行HE染色,计算脊髓前角运动神经元数量,采用免疫组化检测Bcl-2、Bax蛋白表达差异,并计算Bcl-2/Bax比值.结果 A组术后脊髓组织未见明显异常, B、C组术后可见脊髓组织结构紊乱,神经元细胞水肿、坏死.术后1、3、7、14 d, B、C组脊髓前角运动神经元数目均小于A组(P< 0.01).术后3、7、14、28 d, B组脊髓前角运动神经元数目显著多于C组(P< 0.01).B、C组Bcl-2蛋白表达出下降后上升的趋势,分别于术后3、7 d下降至低谷;B、C组Bax蛋白表达呈现出先上升后下降趋势,均于术后3 d上升至高峰;B、C组Bcl-2/Bax比值呈现出先下降后上升趋势,术后3、7、14、28 d, B组Bcl-2/Bax比值显著高于C组(P< 0.01).结论 大鼠下肢同一平面胫神经和腓总神经损伤后都会导致近端脊髓神经元细胞出现凋亡,但是和腓总神经损伤相比,胫神经损伤后对近端神经元退变死亡的影响较小.%Objective To explore the expressions of Bcl-2 and Bax proteins in the neurons of spinal cord after tibial nerve and common peroneal nerve injuries in rats.Methods A total of 90 male SD rats were randomly divided into three groups, the group A was as control group, group B as suture of tibial nerve cut group, and group C as suture of the common peroneal nerve cut group.The L4-6 segment spinal cord of the rats were removed for HE staining and immumohistochemical staining on 3, 7, 14, 28 days after the operation.The number of motor neurons in the spinal anterior horn were calculated.The expressions differences of Bcl-2 and Bax proteins were detected by immuno-histochemistry, and values of Bcl-2/Bax were calculated.Results The number of motor neurons in the anterior horn of spinal cord in group B were less than that in group C on 1, 3, 7, 14, 28 days after the operation (P< 0.01).The expression of Bcl-2 protein in group B and group C showed an upward and then declining trend.It decreased to the lowest on the postoperative 3 d in group B and 7 d in group C, respectively.The expressions of Bax protein in group B and C showed an upward and then declining trend, and it increased to the highest on the postoperative 3 d in groups B and C.The values of Bcl-2/Bax in groups B and C were showed an decreased and then increased trend and it was lower in group B than group C on the postoperative 3, 7, 14, 28 d(P< 0.01).Conclusion Injuries of tibial nerve and common peroneal nerve of the rats would lead the apoptosis of motor neurons in the spinal cord, but compared with the injury of common peroneal nerve, tibial nerve injury would lead less apoptosis of motor neurons.