Blood volume changes in rodents exposed to simulated high altitude

Abstract

Blood volume measurements were made in rats and mice exposed to a simulated altitude of 20,000– 22,000 ft. for periods of 1–4 weeks. The noncapillary blood volume (which includes arteries, veins, arterioles and venules) was determined from plastic-corrosion preparations of the circulatory system. The plasma volume and total blood volume were measured using the T-1824 dye dilution method and capillary volume was calculated by subtracting noncapillary volume from total blood values. The increase in volume of the noncapillary vessels of rats and mice was about 1–2 ml/100 gm body weight after 1–4 weeks of altitude exposure. It was also shown that the total blood volume of acclimatized rats is about 40% greater than that of control animals whereas the plasma volume decreases by about 57%. It was concluded that altitude exposure resulted in a greater increase in the capacity of the noncapillary vessels (ca. 60%) than in that of the capillary bed (ca. 25%).