Changes in the rat thymus cytoarchitectonics during repeated exposure to hypergravitation

Comparative study of the structural and functional changes in rat thymus after 5-day and repeated 5-day exposure to hypergravitation (2g) showed less pronounced changes after repeated exposure. Proliferative potential of thymic lymphocytes was higher and their loss (death) was lower after repeated exposure to hypergravitation, which attested to better adaptation of the thymus during repeated prolonged exposure to hypergravitation than after single exposure of the same intensity and duration. Our findings suggest the possibility of the formation of gravitation memory in thymic lymphocytes during repeated long-term exposure to hypergravitation.