目的 探讨单纯运动神经或感觉神经损伤在骨骼肌萎缩中的致凋亡作用.方法 健康成年SD大鼠30只,随机分为前根切断组(切断左侧L4-L6脊神经前根)、后根切断组(切断左侧L4-L6脊神经后根)和坐骨神经切断组(切断左侧坐骨神经),每组10只.10周后取左右两侧腓肠肌,应用荧光标记、电镜技术以及免疫组化方法 观察单纯运动或感觉神经损伤后骨骼肌细胞的凋亡表现及Fas/FasL的表达变化.结果 失神经支配10周后,骨骼肌细胞出现各种凋亡变化,细胞核凋亡形态明显,其中后根切断组、前根切断组和坐骨神经切断组的细胞核排列密集程度依次增加,Fas/FasL表达依次增强.电镜观察可见失神经支配的骨骼肌细胞未见典型的凋亡小体,但出现凋亡前期的形态改变.结论运动神经损伤对骨骼肌萎缩的影响大于感觉神经损伤,临床治疗失神经支配的骨骼肌萎缩应优先考虑重建运动神经.%Objective To explore the apoptosis-inducing effect of selective sensory or motor nerve injury on skeletal muscle atrophy. Methods Thirty healthy adult SD rats were randomly divided into three groups, namely, ventral root transection group (VRT group, received left L4- L6 ventral rhizotomy), dorsal root transection group (DRT group, received left L4 - L6 dorsal rhizotomy), and sciatic nerve transection group (SNT group, received left sciatic nerve transection). Each group comprised 10 SD rats. The bilateral gastrocnemius was harvested 10 weeks after operation to observe the apoptosis and Fas/FasL expression of the skeletal muscle cells through fluorescent labeling, transmission electron microscopy, and immunohistochemistry. Result Ten weeks after the denervation, apoptosis-related changes, especially obvious changes of the nuclear apoptotic morphology, were observed in the skeletal muscle cells. The aggregation degree of the nucleus and the expression of Fas/FasL increased in the following order: DRT group, VRT group, and SNT group. No apoptotic body, but early apoptotic morphology, was found in the denervated gastrocnemius through transmission electron microscopy. Conclusions The effect of motor nerve injury on skeletal muscle atrophy is more serious than that of sensory nerve injury. The rebuilding of motor nerves should be preferentially considered in the clinical treatment of muscle atrophy induced by denervation.
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