Astronauts are in space, in microgravity and radiation environment. At the same time, they are in a narrow space, isolated from the outside world for a long time, and have to bear high-intensity and high-pressure task loads. The former two belong to the natural environment, while the latter belongs to the social environment, which will affect the immunity of astronauts. In weightlessness, the immune system behaves just like when the body is infected. Because the body doesn't know what to do, it tries to open all possible protection systems.
The decline of immune function in weightlessness is reflected in both nonspecific and specific immune systems. Include lymphocytes and various mediators such as interferon, cell secretions and anti-inflammatory factors. In the experiments of simulated weightlessness on the ground and animals in the sky, the lymphatic organs of animals have shrunk, which is one of the important factors leading to the decline of immunity.
One of the reactions caused by this is the activation of EB virus, which is herpes zoster. Everyone is an EB virus carrier and will be activated if they are in poor health. Studies have found that this virus has a higher activation rate in space, and some astronauts have returned. Under weightlessness, the reproductive ability of microorganisms is enhanced, and the effect of toxins secreted is also enhanced. This trade-off increases the risk of astronauts getting sick.
In addition to weightlessness, astronauts must also deal with radiation. If you receive a large dose of radiation or are hit by heavy ions, your chromosomes will break, which may lead to vomiting and even acute death. But people are more concerned about the effects of long-term radiation accumulation. Because the lymphatic system is a sensitive organ of radiation, if it is affected by radiation, it will also reduce the immune function.
In essence, there is no difference in immune function between space and ground, which is nothing more than three foundations: innate quality, acquired environment and personal status. At present, the cognition of space immune system is still based on the research of ground immunology, but the space environment provides a unique platform for this research. With the advancement of China's manned space mission and the development of medicine, biology and other fields, the understanding of space immunity is becoming more and more abundant. At present, remarkable progress has been made in the division of immune system, physiological and psychological protection of immune system, and microbial control.
In previous manned missions, researchers will continue to follow up and observe the health status of astronauts before, during and after the mission, and take various medical security programs to actively respond. For example, astronauts have various forms of exercise and health care in the sky; The Shenzhou XI mission is equipped with ultrasound equipment, which can be used to observe the vascular structure of astronauts through imaging, heart rate, electrocardiogram and other functional tests. In addition, people are increasingly aware of the importance of astronauts' psychological state. Compared with the early tense flight mission, psychological support was strengthened in the mission design, and astronauts were paid more attention to enjoying the flight in order to maintain a good attitude. "For example, when Shenzhou XI was launched, Jing Haipeng asked Chen Dong if he was happy. This is to help him establish a good mentality of enjoying space, which is conducive to the maintenance of immune function.