VITAMIN-A PRETREATMENT AND BLEOMYCIN-INDUCED RAT LUNG INJURY

Possible antioxidant effects of pretreatment with vitamin A on bleomyc in-induced rat lung injury were studied. Intratracheal bleomycin was a dministered to rats pretreated with vitamin A (50,000 IU/day) or vehic le control. Analysis of bronchoalveolar lavage fluid (BAL) total and d ifferential cell counts, lung weight, lung pathology, and alveolar mac rophage superoxide anion production were performed before and at vario us time points after the instillation of bleomycin. Bleomycin with veh icle raised total BAL cell count and the per cent of BAL neutrophils a t day 7 post injury. The percent of lung involved with pneumonitis, th e lung wet weight/body weight ratio and the alveolar macrophage supero xide anion production were also increased after bleomycin alone compar ed to the group pretreated with vitamin A. Rats pretreated with vitami n A demonstrated a statistically significant reduction in total BAL ce ll count and in alveolar macrophage superoxide anion production 7 days after bleomycin compared with vehicle control. Lung wet weight/body w eight ratio 7 days after bleomycin was reduced in the vitamin A treate d rats. There was a trend to less pneumonitis in the vitamin A pretrea ted group. These data suggest that vitamin A attenuates bleomycin indu ced pulmonary damage by a mechanism which involves inhibition of bleom ycin-induced alveolar macrophage superoxide anion production.