Vitamin A deficiency injures lung and liver parenchyma and impairs function of rat type II pneumocytes

The purpose of this research was to determine the effects of vitamin A defi ciency on liver and lung morphology and type II pneumocyte function. Weanli ng rats were fed a retinol-adequate (control) or -deficient diet for 6 wk, Average food intakes and body weights were not different between the vitami n A-deficient and -adequate rats. Histologic examination revealed that the lungs of vitamin A-deficient rats had less collagen in the adventitia of sm all caliber arteries and arterioles and in the alveolar septa, which appear ed thinner than that of controls. Many areas of the lungs of the same rats were also emphysematous (increased size of air spaces distal to the termina l bronchiole, with thinning and partial or total destruction of septal wall ). Content of elastin also was lower in the lung parenchyma, as well as in the small arteries and arterioles, but not in the larger ones. Peribronchia l collagen was not affected by the deficient diet, Scattered inflammation w as observed in most of the vitamin A-deficient rats; a mild inflammatory re action also was seen in one of the controls. Vitamin A-deficient rats also exhibited hepatocyte vacuolization and mild inflammation in the liver, spec ifically in the periportal tracts. Surfactant synthesis and ornithine decar boxylase activity were significantly lower in type II pneumocytes isolated from vitamin A-deficient rats. In conclusion, our data provide evidence tha t vitamin A deficiency produces profound morphologic alterations in liver a nd lung parenchyma and impairs pneumocyte function.