尾吊大鼠恢复负荷后肌萎缩和骨丢失的差异响应

Diverse Response of Muscle and Bone in Reloading of Hindlimb Unloaded Rat

目的探讨恢复负荷过程中,下肢不同部位的肌萎缩与骨丢失的恢复特征。方法对比尾吊3周及恢复负荷1周的大鼠,心肌和4种后肢骨骼肌以及股骨、胫骨骨密度和股骨力学性能在失负荷和恢复负荷过程中的特征变化。结果失负荷引起的萎缩主要为比目鱼肌,还包括腓肠肌和胫骨前肌;恢复负荷后,比目鱼肌首先部分恢复;失负荷引起股骨、胫骨骨密度及股骨力学性能的下降,恢复负荷后没有改善,胫骨骨密度进一步下降。结论恢复负荷过程中肌萎缩的修复先于骨丢失的恢复,后肢骨骼肌中对于负荷敏感性依次为比目鱼肌、腓肠肌、胫骨前肌、趾长伸肌;胫骨在恢复负荷早期存在持续性骨丢失特征。

Objective To explore the differences of hindlimb muscles and bones in responding to reloading of rat soleus after hindlimb unloading. Methods We compared the alterations of heart and four hindlimb skeletal muscles, the bone mineral density of femur and tibia, and the mechanical parameters of femur in the process of 1-week reloading in 3-week unloaded rats. Results Unloading mainly caused atrophy of soleus,so did gastrocnemius and tibialis anterior; the atropic soleus was partly recovered firstly; unloading led to a decrease of bone mineral density （BMD） of femur and tibia,and mechanical parameters of femur,which was not recovered after reloading, while the tibia BMD further decreased. Conclusion The recovery of muscle atrophy is prior to that of bone loss following the reloading, and the susceptibility to loading exhibited in an order of soleus, gastrocnemius, tibialis anterior and extensor digitorum longus in the hindlimb muscles. Notably, tibia showed a persistently bone loss in the early stage of reloading.