Specifics of Microcirculation under the Conditions of “Dry” Immersion

Abstract

Peripheral hemodynamics was studied in the upper extremities of human subjects during a 5-day exposure in microgravity modeled by “dry” immersion (DI). The object of investigation was skin adjacent to the nail bed of the fourth finger and forearm skin. Microcirculation was measured using laser Doppler flowmetry (LDF) and computer capillaroscopy (CCS). In addition, peripheral hemodynamics was assessed in subjects donned in a Penguin axial-loading suit (PLS). The subjects were divided into two groups: with (G-2) and without (G-1) PLS. The results are the following: PLS leveled down all changes in the microcirculatory bloodstream (MCB) of the upper extremities. By the end of DI, some subjects in G-1 were found to have a more intensive tissue perfusion and increased number of capillaries, and exaggerated activity of passive mechanism of blood flow modulation Ас (one-way ANOVA, p < 0.05).