大鼠失神经支配后比目鱼肌和趾长伸肌超微结构变化的实验研究

Ultrastructural changes after denervation of soleus and extensor digitorum longus

目的:探讨比目鱼肌和趾长伸肌失神经支配后不同时间点超微结构变化。方法:建立SD大鼠坐骨神经离断模型,分别于术后1,2,3,4周电镜下观察大鼠比目鱼肌和趾长伸肌的超微结构变化。结果:失神经支配1周,比目鱼肌纤维局部萎缩变细,肌丝排列不规则,部分线粒体出现肿胀;趾长伸肌的肌丝排列稍不规则,线粒体形态等无明显异常。失神经支配2周比目鱼肌萎缩变细加重,肌节与肌丝排列紊乱,部分线粒体空泡变性;趾长伸肌的肌丝局部萎缩变细,肌间隙增宽,线粒体发生轻微肿胀。失神经支配后3、4周,比目鱼肌肌节肌丝变化明显,结构模糊不清,线粒体呈空泡化;趾长伸肌的肌丝排列不规则,肌原纤维结构可辨,线粒体肿胀明显,部分出现空泡化。结论:周围神经损伤可致骨骼肌超微结构发生明显变化,并随着失神经支配时间延长而逐渐加重;比目鱼肌失神经支配后超微结构的变化较趾长伸肌明显。

Objective： To observe the ultrastructural changes in soleus and extensor digitorum longus at different time points after denervation.Methods： The model of denervation was established in SD rats.Soleus and extensor digitorum longus were harvested at different time points after denervation.The ultrastructures of the samples were observed by electron microscope.Results： One week after denervation,for soleus muscle,fibers became atrophied and thinner,myofilaments arranged irregularly,and some mitochondria swollen;for extensor digitorum longus,myofilaments were slightly irregularly arranged,and the mitochondrial morphology showed no obvious changes.Two weeks after denervation,the degree of soleus atrophy was more serious,its myofilament and sarcomere were arranged disorderly with vacuolar degeneration in some mitochondria;the gap of extensor digitorum longus muscle was widened and mitochondria were swollen.At three and four weeks after denervation,sarcomere of soleus muscle changed obviously,mitochondrial structure was unclear and vacuolated;myofilaments of extensor digitorum longus were arranged disorderly,swelling and some vacuolar degeneration of its mitochondria were observed.Conclusion： Peripheral nerve injury could induce time-related changes in the ultrastructure of denervated muscles.It was noted that the ultrastructural changes were more serious in denervated soleus than in denervated extensor digitorum longus.