[Quantitative changes in the ultrastructure of myocardial cells in Japanese quail during hypergravity, hypodynamia...

The experimental work aimed at the quantitative ultrastructure of the myocardial cells of the Japanese quail Coturnix coturnix japonica during hypergravitation, hypodynamism and space flight in a Soviet satellite. For the determination of quantitative changes of the myocardial ultrastructure a morphometrical method was used with parameters like the number of mitochondria, average mitochondrial size, relative mitochondrial volume, deficiency of cristae and relative volume of myofibrils. The quails were observed in 3 groups. The absolute control consisted of quails living in normal Earth conditions, in the laboratory group the quails were exposed to conditions of hypergravitation and hypodynamism in a specially constructed centrifuge, and in the flying group the quails were exposed to space flight in a Soviet orbital station MIR. In the group of absolute controls no pathological changes of the myocardial ultrastructure were found. In the flying group there were no significant changes, with the exception of decreased relative volume of myofibrils, which however agrees with the findings on symptoms corresponding to human and animal heart weakness during space flights. In the laboratory group, pathological changes were observed in each of the fractions. The most significant pathological findings were found in the group controls in the center and in hypergravitation combined with hypodynamism. It can be concluded that the laboratories can simulate conditions induced by the start and flight of space ships. (Fig. 2, Ref, 8.)