No abstract

The effects of stress in space, microgravity and space radiation, on living organisms are still unknown. We have examined the cellular content of p53 protein, a tumor-suppressor gene product, in skin from rats by the Western blot method using a blotting-amplification system. Three groups of rats were used. The first group was kept on Earth normally and showed hardly any detectable p53 protein. The second group made a 14-day flight into space on the second Spacelab Life Sciences-2 mission (F). The last group was subjected to the same kinds of stress as the rats in the second group except for spaceflight (SC). The F and the SC rats were killed on day zero (F-0 and SC-0 groups) and day nine (F-9 and SC-9 groups) after return. F-0 rats showed marked accumulation of p53 protein, whereas SC-0 rats showed a slight decrease. F-9 and SC-9 rats showed almost the same amount of p53 protein, but F-9 rats showed a slightly higher expression. From these results, it is suggested that the accumulation of cellular p53 protein is induced in rat skin cells by exposure to the space environment.