Structural and metabolic characteristics of human skeletal muscle following 30 days of simulated microgravity.

摘要: Percutaneous needle biopsy samples were obtained from the vastus lateralis and soleus muscles before after 30 d of 6 degree head-down bedrest to determine influence this model simulated microgravity on human skeletal muscle. Fiber atrophy was evident in both with fast-twitch slow-twitch fiber cross-sectional areas decreasing. Predominant fibers not evident. The had a greater proportion than bedrest. Neither muscle showed change type percentage Phosphofructokinase lactate dehydrogenase activities similar beta-hydroxyacyl-CoA citrate synthase, however, reduced during these responses being somewhat soleus. While ultrastructure most appeared normal bedrest, evidence remodeling present muscles. proliferation core/targetoid lesions, honeycomb networks, regenerating satellite cells, necrotic foci myofibrillar disorganization indicates that force development is an important factor determining organization fine structure results indicate short-duration exposure decreases size capacity for aerobic energy supply Moreover, contractile machinery occurs. Thus, it appears alters "normal" load-time constraints imposed sufficiently its inherent structural metabolic characteristics.