[Morphologic and cytochemical research aboard the biosatellite "Cosmos-782"].

Organs of rats flown for 19.5 days on board the Cosmos-782 biosatellite were investigated morphologically and cytochemically. After flight, as a result of drastic decrease or loss of static load on the musculeskeletal system in zero-g, the rats developed mineral metabolism changes that morphologically appeared as osteoporosis of spongy bones, their periosteocytic osteolysis, as well as inhibition of red blood cell precursors in bone marrow, atrophy and dystrophy of skeletal muscles. The development of stress-reaction which seemed to increase at certain flight stages (launch and re-entry) and weightlessness--1 g transition brought about changes in the structure and cell composition of lymph organs, changes in the hypothalamic-pituitary-neurosecretory system, adrenals, gastro-intestinal tract and other organs and systems. Changes in the receptor system of the inner ear resulted, evidently, from weightlessness and acceleration effects, whereas retinal lesions were due to heavy charged particles of cosmic radiation. The changes noted were reversible and 25 days after flight returned, completely or partly, to the normal.