模拟失重对大鼠比目鱼肌肌重和形态结构的影响

Effects of the simulated weightlessness on weight of the rat soleus muscle and its morphology

目的 研究模拟失重对大鼠抗重力肌—比目鱼肌的湿重、干重及形态结构的影响.方法 采用健康雌性Sprague-Dawlwy大鼠117只,按照体重配对原则随机分悬吊各组及其各自的对照组.采用组织学方法和透射电镜观察尾部悬吊法模拟失重状态下,比目鱼肌干、湿重体重比的变化,以及肌纤维的光镜结构与超微结构的变化.结果 与对照组相比,比目鱼肌干重体重比、湿重体重比在悬吊7d组即明显下降,悬吊14d组达峰值,此后有所回升.悬吊14d后的比目鱼肌,光镜下肌束结构紊乱,肌纤维面积和面积构成减少,肌纤维间间隙加大,结缔组织增生.电镜下可见肌原纤维分解,局部溶解,Z线排列紊乱、中断,肥厚层破坏,部分的纹带中出现坏死区.以上变化在解除悬吊7d时不能完全恢复.结论 尾部悬吊可致大鼠比目鱼肌萎缩,光镜结构和超微结构出现异常改变.

Objective To explore effects of the simulated weightlessness on wet weight and dry weight of the rat soleus muscle and its microscopic and ultrastructural morphology.Methods The 117 Sprague-Dawley rats were divided into ten groups,that is ,3 days,7 days,14 days,30 days of suspension group and 7 days of recovery group and their controls. Using histological technique and electron micoroscopy, changes of morphological structures in the rat soleus muscle were investigated under light and electron microscope after different suspension pe-riods , in addition to ratios of wet and dry muscle weight to body weight. Results The ratios of wet and dry muscle weight to body weight begun to be decreased after 7 days,and the maximal decrease occurred after 14 days of suspension.The ratios had not returned to control levels after 7 days of recovery following 30 days of suspension. Muscle bundle appeared disordered, and area of myofiber and its composition decreased, and gap around muscle fiber enlarged,and connective tissue proliferated in suspension group. Local fibrillium was dissolved,and Z-line had come to irregular and its contituity had been destroyed, and necrotic phenomena appeared in part of the bands under electron microscopy. Conclusion The tail suspension may result in loss of muscle mass and changes in morphological structure of the rat soleus muscle.