Relative immunity to arteriosclerosis in rabbits during the hair-shedding period

Abstract

The extent and severity of arteriosclerosis in rabbit aorta induced by exposure to short periods of systemic hypoxia for two weeks were studied during the hair-shedding period (September through December). Two series of experiments were carried out in relation to two different shedding periods with an interval of 1 year. The entire study involved 152 rabbits. Three experiments were performed in shedding and three in nonshedding periods. While shedding, the rabbits exposed to hypoxia developed slight gross arteriosclerosis in contrast to the severe arteriosclerosis that developed while the animals were not shedding. Qualitatively, the gross and microscopic changes did not differ during and outside the shedding periods. Comparison of the biochemical changes in the aortic acid mucopolysaccharides and collagen induced by the systemic hypoxia during the shedding and nonshedding periods showed no statistically significant differences. The resistance to arteriosclerosis during shedding may be due to hormonal factors, which also may be of importance to the development of arteriosclerosis in other species. Furthermore, the phenomenon has to be taken into consideration in experimental studies of rabbit arteriosclerosis.