[Effect of conditioning to altitude hypoxia on mesenteric microcirculation in rats]

A long-term training of rats to high-altitude hypoxia (in an altitude chamber at the height of 6500 m, 6 hours daily, for 30 to 40 days) results in a significant hyperemia of their intestinal wall and mesentery. The number of functioning capillaries of trained rats exceeded that of control animals several times, but the blood flow was slowed down in the dilated vessels and their structure was altered. Besides an obvious increase in blood rachemia in the arteries and veins, its rarefaction is observed in the capillaries. Definite hemorheological changes, probably associated with polycythemia, and an increased hematocrite index were noted.