Structural Parameters of Mesenteric Lymph Nodes in Mice Exposed to Factors of Modeled Aerial Environment of Space Vehicles

Abstract

The effects of inhalation exposure to a mixture containing acetone, acetaldehyde, and ethanol in concentrations typical of closed environment in space vehicles on the structure of mesenteric lymph nodes in F1 male mice were studied by histological technique. The long-term exposure to modeled atmosphere led to pronounced structural changes in these nodes that were clearly seen on day 22 and increased by day 36 of the experiment. The thickness of the capsule and trabeculae of mesenteric lymph nodes as well as diameter of lymphatic sinuses did not differ from the control values up to day 8, but then increased on days 22-70. Starting from day 22, the thickness of the medullary cords decreased and attained the minimum to the end of the experiments, which can indicate depletion of immunocytopoiesis and inhibition of humoral immunity. The present data are important for the space medicine, because they indicate structural changes in the peripheral lymphoid organs, the key elements of immune system.