IZMENENIYa KOSTNOY TKANI ChELOVEKA V KOSMIChESKOM POLETE II. NEKOTORYE ZAKONOMERNOSTI I OSOBENNOSTI

Abstract

There are considered possible mechanisms of some peculiarities of cosmonauts bone tissue changes after space flights 5-7 month duration, that were diagnosed using dual energy X-ray absoptiometry (DEXA). Local osteopenia in spongy bone of the body lower part may be connected with big weight bearing load in 1g conditions. Increasing of mineral content in upper part of the skeleton and hypermineralization of vertebrae body spongy bone, that were showed by computer tomography possible are the secondary effects and are connected with fluid redistribution to cranial direction, including abdomen. Additional negative gradient of bone mass in bones of lower part of skeleton, that is observed in early period of readaptation (till 1 month) may be explained as result of acceleration of bone remodeling (resorption and formation of bone), as reaction to recover of loading. Individual variability of above mentioned reactions is connected with genetically determined initial bone mass and phenotype of bone metabolism. There are considered possibilities of genetic prediction of osteopenia in discussed conditions.