模拟失重对大鼠比目鱼肌肌梭超微结构的影响

目的 观察模拟失重不同时期大鼠比目鱼肌肌梭超微结构的改变。方法 采用大鼠尾部悬吊法建立模拟失重模型。雌性大鼠随机分为模拟失重4、7、14d组和模拟失重14d后恢复14d组，以及各组的对照组。分坦肌梭，用透射电镜观察模拟失重不同时期比目鱼肌肌梭超微结构的改变。结果 模拟失重4d组大鼠比目鱼肌肌梭的超微结构有较明显的改变，表现为部分肌原纤维排列略见紊乱，线粒体增生、肿胀、终末池明显扩张等。模拟失重7d组肌梭的超微结构改变更为明显。模拟失重14d组肌梭超微结构改变显著，可见严重的退行性改变，超微结构模糊不清，细胞核固缩，线粒增生、肿胀、线粒体嵴模糊、减少、消失，Z线排列紊乱，部分溶解消失，肌浆网终末池高度扩张。模拟失重14d后恢复14d组肌梭超微结构基本恢复正常。结论：模拟失重可致肌梭超微结构发生明显的、可逆性的改变，随模拟失重时间延长而加重。

Effects of Simulated Weightlessness on Ultrastructure of Soleus Muscle Spindle in Rats

Objective To study changes in ultrastructure of soleus muscle spindle induced by simulated weightlessness in rats. Method Weightlessness was simulated by tail suspension in female rats. The ultrastructure of isolated soleus muscle spindle were observed in 4 d, 7 d, 14 d tail suspended and 14 d recovered rats. Result Chaotic myofibril, hyperplasia of mitochondria, and enlargement of terminal cisterna were found in the ultrastructure of isolated soleus muscle spindle in 4 d tail suspended rats. The ultrastructure of isolated soleus muscle spindle in 7 d tail suspended rats showed more distinct changes, while that in 14 d tail suspended rats showed obvious retrograde changes. The ultrastructure of isolated muscle spindle in 14 d recovered rats after 14 d tail suspension were similar to that of control group. Conclusion Simulated weightlessness could induce time related and reversible changes in ultrastructure of soleus muscle spindle in rats.