Study of the Expression of Integrins in Smooth Myocytes of the Gastrointestinal Organs After Space Flight.

Spaceflight has crucial effects on living organisms, primarily due to weightlessness, which causes essential morphofunctional changes in the tissues of almost all body systems. Smooth muscle tissue is one of the main system-forming components of the gastrointestinal tract, which makes its study particularly relevant to space gastroenterology. Integrins are cell adhesion receptors expressed in practically all cell types, including smooth muscle cells. By mediating interactions with the extracellular matrix and intercellular signaling, smooth muscle cell integrins actively participate in adaptation to microgravity conditions. However, this aspect of smooth muscle tissue function has not been addressed in space gastroenterology until now. The aim of the study was to investigate the expressions of integrins alpha-5, alpha-2, and alpha-1 expression in smooth myocytes of the gastric and jejunal muscular layer in Mongolian gerbils (Meriones unguiculatus) after a 12-day spaceflight, which was part of the Foton M-3 project. We detected a slight increase in integrin alpha-1 expression, a trend toward decreased integrin alpha-2 expression, and a significant decrease in integrin alpha-5 expression in the gastric and jejunal muscularis propria in Mongolian gerbils from the spaceflight group, which may indicate weakened interactions between cells and the extracellular matrix and potentially lead to reduced smooth muscle contractility. Research on the fundamental role of integrins in the development of the digestive system adaptive mechanisms to zero-gravity conditions may be useful in developing preventive measures to mitigate the risk of gastrointestinal smooth muscle hypotrophy and maintain the health of astronauts during their professional activities aboard the ISS.