[Combined action of space flight and radiation factors on the skeletal musculature of rats].

A prolonged irradiation of rats at a dose of 800 rad on their 10th day of flight aboard the biosatellite Cosmos-690 aggravated the severity of weightlessness- and hypokinesia-induced atrophic and dystrophic processes in the soleus muscle and the atrophic process in the gastrocnemius muscle. These space flight factors did not influence the muscles (biceps brachii, extensor digitorum longus), in which no flight-associated pathologies occurred. Radiation exposure altered the pattern of reparation in the areas of the soleus muscle that developed pathological changes, and delayed resorption which occurred during the pathological process of the connective tissue, which resulted in an inhibition of the reparation process.