Ozone-induced alterations in collagen metabolism of monkey lungs: Use of biopsy-obtained lung tissue

Open-chest biopsies of lung were performed on three cynomolgus monkeys (Macaca fascicularis) 4-6 weeks before and immediately after exposure to 1.5 ppm of ozone for 1 week. Two control monkeys were subjected to comparable procedures, but were exposed to filtered air for 1 week immediately prior to the second biopsy. Collagen synthesis rate of each lung biopsy specimen was determined. Enhanced rates of collagen synthesis were observed in the lung biopsy specimens obtained from the monkeys exposed to ozone; elevated rates of collagen synthesis were not observed in lung biopsy specimens from the two monkeys undergoing identical surgical procedures but not exposed to ozone. We conclude that exposures of monkeys to high levels of ozone caused increased rates of collagen synthesis in their lungs, suggesting that the ozone-induced fibrotic changes observed previously in rat lungs also occur in lungs anatomically similar to those of humans. This experimental design, in which each animal serves as its own control, is a practical way to perform such exposure experiments using small numbers of valuable animals.