[Metabolic and structural aspects of cellular homeostasis in long-term isolation]

Metabolism and structural/functional status of membrane of blood cells (erythrocytes, lymphocytes) were investigated in human subjects during simulation of MIR environment and operations, and postflight activities. Homeostasis of the blood count cells was assessed by the parameters of intercellular metabolism. Histochemical technique was used to evaluate the activity of mitochondrial enzymes succinate dehydrogenase and alpha-glycerphosphate dehydrogenase in lymphocytes. State of the erythrocyte membrane was judged about by the lipid and phospholipid spectra, activity of transport ATPase and shape of erythrocytes were determined with the electronscan microscopy. Adaptational shifts in erythrocyte metabolism were particularly marked on days 22 and 113 in the experiment, and day 1 of recovery. They appear to be associated with alterations on the membrane level. Therefore, simulation of a long-term MIR mission produces changes in cellular metabolism and status of cellular membranes concurrent to the readjustment of body controls due to, probably, shifts in the sympathoadrenal system. Destabilization of the cellular membrane could be also linked with plasmic factors, e.g. increases in bile acids, lysolecithin, Ca ions, etc., in consequence to changes in lipid metabolism and electrolyte status.