Kourtidou-Papadeli Chrysoula, Kyparos Antonios, Albani Maria, Frossinis Athanasios, Papadelis Christos L, Bamidis Panagiotis, Vivas Ana, Guiba-Tziampiri Olympia
Aristotle University of Thessaloniki, School of Medicine, Laboratory of Experimental Physiology, Thessaloniki, Greece.
Acta Astronaut. 2004 May;54(10):737-47. doi: 10.1016/j.actaastro.2003.10.001.
The perspective of long-duration flights for future exploration, imply more research in the field of human adaptation. Previous studies in rat muscles hindlimb suspension (HLS), indicated muscle atrophy and a change of fibre composition from slow-to-fast twitch types. However, the contractile responses to long-term unloading is still unclear. Fifteen adult Wistar rats were studied in 45 and 70 days of muscle unweighting and soleus (SOL) muscle as well as extensor digitorum longus (EDL) were prepared for electrophysiological recordings (single, twitch, tetanic contraction and fatigue) and histochemical stainings. The loss of muscle mass observed was greater in the soleus muscle. The analysis of electrophysiological properties of both EDL and SOL showed significant main effects of group, of number of unweighting days and fatigue properties. Single contraction for soleus muscle remained unchanged but there was statistically significant difference for tetanic contraction and fatigue. Fatigue index showed a decrease for the control rats, but increase for the HLS rats. According to the histochemical findings there was a shift from oxidative to glycolytic metabolism during HLS. The data suggested that muscles atrophied, but they presented an adaptation pattern, while their endurance in fatigue was decreased.
从未来探索的长期飞行角度来看，意味着在人类适应领域需要更多研究。先前对大鼠后肢悬吊（HLS）肌肉的研究表明，肌肉会出现萎缩，并且纤维组成会从慢肌纤维类型转变为快肌纤维类型。然而，长期失重对肌肉收缩反应的影响仍不明确。对15只成年Wistar大鼠进行了45天和70天的肌肉失重研究，并对其比目鱼肌（SOL）和趾长伸肌（EDL）进行了电生理记录（单收缩、抽搐、强直收缩和疲劳）以及组织化学染色。观察到比目鱼肌的肌肉质量损失更大。对EDL和SOL的电生理特性分析显示，组、失重天数和疲劳特性均有显著的主效应。比目鱼肌的单收缩保持不变，但强直收缩和疲劳方面存在统计学上的显著差异。疲劳指数显示对照组大鼠下降，而HLS组大鼠上升。根据组织化学研究结果，在HLS期间，肌肉代谢从氧化代谢转变为糖酵解代谢。数据表明，肌肉出现萎缩，但呈现出一种适应模式，同时其疲劳耐力下降。
