Space flight effects on the skeletal muscles of rats.

Morphological and histochemical examinations of the skeletal muscles of rats flown for 22 d aboard the Cosmos-605 biosatellite have demonstrated atrophic and dystrophic developments in the soleus muscle accompanied by metabolic changes in the muscle tissue. The changes were reversible but did not disappear entirely 27 d postflight. Early atrophic developments were seen in the m. gastrocnemius, m. quadriceps, and m. ext. digitorum longus on the second postflight day. The comparative study of the muscles of flight and simulation rats has shown that pathology developed in the muscles as a result of diminished motor activity of animals being aggravated by weightlessness.