Podlubnaia Z A, Vikhliantsev I M, Mukhina A M, Nemirovskaia T L, Shenkman B S
Biofizika. 2004 May-Jun;49(3):424-9.
Changes in sarcomeric cytoskeletal proteins of rat m. soleus fibers upon the chronic stretching against the background of gravitational unloading were analyzed and compared with changes in fiber size and myosin phenotype. For rats exposed to gravitational unloading in the usual microgravity-simulating experimental model (hindlimb suspension (HS) according to Morey-Holten), a considerable reduction in the mass of m. soleus (by 54%) and the area of its fibers of both slow-twitch (by 47%) and fast-twitch (37%) types compared with control animals was revealed. Moreover, the percent of fibers containing only slow isoforms of myosin heavy chains (MHC) for suspended animals was slightly smaller and the portion of fibers interacting only with antibodies against fast myosin isoforms was significantly higher than for control animals. For hindlimb-suspended rats, the titin/MHC and nebulin/MHC ratios appeared to be reduced almost by two times as compared with those for the contriol group of animals. Chronic immobilization of m. soleus in stretched state against the background of suspension leads to a partial or complete prevention of the reduction in muscle fiber sizes, the transformation of the myosin phenotype into fast one, and a decrease in relative content of sarcomeric cytoskeletal proteins.
分析了在重力卸载背景下大鼠比目鱼肌纤维肌节细胞骨架蛋白的变化，并将其与纤维大小和肌球蛋白表型的变化进行了比较。对于在常规模拟微重力实验模型（根据莫雷 - 霍尔滕法进行后肢悬吊（HS））中暴露于重力卸载的大鼠，与对照动物相比，比目鱼肌质量显著降低（降低54%），其慢肌纤维（降低47%）和快肌纤维（降低37%）的面积也显著降低。此外，与对照动物相比，悬吊动物中仅含有肌球蛋白重链（MHC）慢异构体的纤维百分比略小，而仅与抗快肌球蛋白异构体抗体相互作用的纤维比例显著更高。对于后肢悬吊的大鼠，与对照组动物相比，肌联蛋白/MHC和伴肌动蛋白/MHC的比率似乎降低了近两倍。在悬吊背景下将比目鱼肌长期固定在拉伸状态可部分或完全防止肌纤维大小的减小、肌球蛋白表型向快肌型的转变以及肌节细胞骨架蛋白相对含量的降低。
