Roffino S, Carnino A, Charpiot P, Marini J F
Faculté des sciences du sport, Université de la Méditerranée, Marseille, France.
C R Acad Sci III. 1998 Jul;321(7):557-64. doi: 10.1016/s0764-4469(98)80457-5.
Myotendinous junctions (MTJs) transmit contractile force from skeletal muscles to tendons. The effects of a 14-d spaceflight on MTJ were studied in the soleus muscle of male adult Sprague Dawley rats by transmission electron microscopy and histomorphometric techniques. We showed that the length of the junctional membrane relative to the muscle fiber diameter increased by 58% after 14 d of spaceflight. This increase accompanies morphological changes at MTJs. The flight MTJs appeared more shredded. The ends of the muscle fibers exhibited T tubule dilatation, swollen mitochondria, Z-disk streaming, loss of myofilaments, a thinning down of subplasmalemmal densitites, multivesicular bodies and signs of junctional membrane and basal lamina remodelling. The ultrastructural observations suggest that the increase in myotendinous interface could result from the extracellular matrix spreading into remodelling muscle fiber, whereas the constraints related to unloading were reduced by spaceflight conditions.
肌腱连接点（MTJ）将骨骼肌的收缩力传递至肌腱。通过透射电子显微镜和组织形态计量学技术，研究了14天太空飞行对成年雄性Sprague Dawley大鼠比目鱼肌中MTJ的影响。我们发现，太空飞行14天后，连接膜长度相对于肌纤维直径增加了58%。这种增加伴随着MTJ处的形态学变化。飞行组的MTJ显得更加破碎。肌纤维末端出现横小管扩张、线粒体肿胀、Z线流、肌丝丢失、肌膜下致密物质变薄、多囊泡体以及连接膜和基膜重塑的迹象。超微结构观察表明，肌腱-肌肉界面的增加可能是由于细胞外基质扩散到重塑的肌纤维中，而太空飞行条件减轻了与失重相关的限制。
