A joint research group of the Institute of Physical and Chemical Research, Tsukuba University, Aerospace Research and Development Organization, and the University of Tokyo has found that in a zero-gravity environment of space, the lymphatic organ "thymus" atrophies, and the atrophy is reduced by artificial gravity load. We also discovered a mechanism by which atrophy occurs when the proliferation of thymocytes is suppressed.
The immune system, which is important for biological defense, is affected by staying in space.It is thought that when the immune function declines, reactivation of herpesvirus and the like occurs.Studies examining astronaut blood have shown that T lymphocytes immediately after production in the thymus decrease when they stay in space.Since it is difficult to investigate the effects on human lymphatic organs in detail, studies using mice were conducted.
This time, the joint research group bred mice for about a month at the Japanese Experiment Module "Kibo" on the International Space Station (ISS), and investigated the effects of weightlessness on the thymus.At that time, some mice were bred to receive the same gravity (1G) as on the earth by using centrifugal force.The thymus of mice reared in a weightless space environment atrophied more than mice reared on the ground, but artificially loaded with 1G in the ISS significantly reduced thymus atrophy.
In addition, the genes expressed in the thymus of each mouse were comprehensively analyzed, and the mechanism of thymus atrophy due to staying in space was investigated.As a result, genes involved in cell proliferation decreased in the thymus of mice reared under zero gravity.As a result, when weightlessness is experienced in the space environment, thymocyte proliferation is suppressed and thymic atrophy is thought to occur.
This result clarifies the relationship between the thymus, which is involved in immune function, and gravity, and is useful for health management and prevention of immune system abnormalities necessary for future manned exploration of the Moon and Mars, private space travel, etc. It can be expected to contribute.
Paper information:[Scientific Reports] Impact of spaceflight on the murine thymus and mitigation by exposure to artificial gravity during spaceflight