Gastric mast cell population in rats under ground-simulated weightlessness conditions and in early readaptation period

Abstract

   The effect of altered gravity on the digestive system is one of the challenging issues in space biology and medicine. The study of the effect of weightlessness on the mast cell (MC) functioning in the gastrointestinal organs is determined by their multifunctionality and participation in the developing adaptive and pathological processes.   The aim of the study was to investigate the morphofunctional state of MCs in the stomach membranes of Wistar rats during 14 days of ground-based simulated weightlessness conditions and in a 3-day recovery period.   Material and methods. The experiment involved 3 groups of Wistar rats: control, experimental – exposed to antiorthostatic suspension – and a 3-day-recovery group, 7 animals each, respectively. Identification of MCs was carried out using May-Grunwald staining with additional staining with Giemsa solution and immunohistochemical tryptase detection. The results obtained were statistically processed with SPSS 13 using parametric and non-parametric criteria.   Results. A significantly increased number of metachromatic MC population was found only in the mucosa in animals of the antiorthostatic suspension and 3-day-recovery groups compared to the vivarium control. There was a sharp decrease in degranulating forms of MCs in the submucosalcoat in animals of the 3-day-recovery group compared to the control. A significantly increased number of degranulating forms of MCs was revealed in the muscle membrane in animals of the antiorthostatic suspension group. Immunohistochemical staining of MCs with antibodies to tryptase, in contrast to staining for metachromasia, allowed identifying a significant representation of tryptase-positive cells in the gastric mucosa in animals of the 3-day-recovery group.   Conclusion. The results obtained support gravisensitivity of certain structural components of the stomach, and also evidence MC and their secretome participation in the developing adaptive responses to the effects of altered gravity both at the cellular and tissue levels.