Effect of Short-term Space Flight on Structure of Liver, Lungs, Bone and Bone arrow of Japanese Quail Hatched on Orbital Station Mir

Abstract

The effect of hypergravity of launch, microgravity during short-term space flight, and hypergravity of landing on the structure of liver, lung, bone and bone marrow of 3 Japanese quail, that hatched on board the orbital station Mir was investigated. Chicks were 5 days old at landing. Eleven hours after landing 3 male chicks were killed and samples were collected for a wide variety of biochemical, histological, histochemical, electron microscopic and microbiological investigations. Results of the light microscopic, and transmission electron microscopic study are presented in this paper. Extensive deposits of fat droplets were revealed in almost all hepatocytes of all flight chicks versus ground and laboratory controls. Adipocytes, common in the bone marrow of control animals of the same age, were depleted or absent in bone marrow of flight chicks. There were no substantial effects on the structure/ultrastructure of the lungs, the structure of the bone and its development was not substantially affected. Morphometry of the liver revealed that hepatocytes contained significantly more lipid droplets (nearly 5-fold) than hepatocytes of ground control chicks of the same age hatched at the same time. Morphometric study of lungs revealed no significant difference in number, diameter and total surface of air capillaries between flight and control chicks of the same age.We propose that structural changes in the liver and bone marrow were not caused by direct effect of microgravity per se, but most probably resulted from an insufficient intake of feed due to stress of the microgravity environment and the resulting delay in uptake of lipids from liver. We suppose that these structural changes are the tissue and cellular response to microgravity and they are consistent with literature data known as "space adaptation syndrome". Japanese quails, space flight, effect of microgravity, light and electron microscopyAbility of humans to be sustained in space, whether in orbital space labs and stations or during future long-distance space missions requires supplementing the astronauts' diet. Birds appear to be the most effective converters of plant biomass to animal proteins in an closed system. Among birds, the Japanese quail is considered the most advantageous for spaceflight travel as it has very high rate of reproduction and in relation to its body weight the Japanese quail produces 2.5 times more egg biomass than the domesticated chicken. The orbital station or spacecraft constitute an artificial closed ecosystem operating near 0-G (in weightlessness or microgravity) conditions (Boìa 1993). Accordingly, it is necessary to know in detail the life cycle of Japanese quail, particularly stages sensitive to microgravity or weightlessness, i.e., the production of gametes, fertilization, critical stages of embryogenesis, hatching, early post-incubation development, growth, and maturation. The aim of this study was to investigate the effect of microgravity during brief space flight on ACTA VET. BRNO 2005, 74: 167-174

Potential Roles of YAP/TAZ Mechanotransduction in Spaceflight-Induced Liver Dysfunction

“…Microgravity-induced liver dysfunction is a challenge, especially in long-duration space missions (Table 1). Japanese quail on board the orbital station Mir for 5 days displayed extensive deposits of lipid droplets in almost all hepatocytes of all the flight chicks, and the overall amount of lipid droplets was nearly 5-fold higher than ground control chicks [17]. Meanwhile, the accumulation of lipids in the liver led to a depletion of adipocytes in the bone marrow of these flight chicks.…”