The Effect of Vitamin A Deficiency in Rabbits on the Elastic Properties of the Lung and Thoracic Aorta
Weanling rabbits were fed a vitamin A deficient diet for 6 weeks. During this period they failed to gain weight normally and exhibited significantly lower serum vitamin A levels when compared with their littermates fed a vitamin A supplemented diet. These findings indicated that vitamin A deficiency was established, and the lungs and specimens of aorta were removed for study. The pressure–volume relationships of saline-filled lungs revealed that test lungs were more compliant than control lungs and this difference was associated with a decrease in elastin content in test lungs. The absence of such changes in pair-fed controls suggests that the effects are due to vitamin A deficiency per se rather than the general effects of retarded growth. A decrease was also noted in the elastance of the aorta, confirming that vitamin A deficiency has an effect on elasticity of tissues generally. When vitamin A deficient animals were given vitamin A supplemented diets the elastance of the aorta returned to control values but the compliance of the lung, although somewhat decreased, did not reach control values. The mechanism by which vitamin A deficiency affects tissue elasticity is not known.