Effects of intermittent hyperbaric oxygen on guinea pig lung elastin and collagen

The effect of high oxygen pressure on collagen and elastin turnover in lung parenchyma tissue was studied in guinea pigs. Three groups of animals was used. One group (I) was given a clinically excessive exposure of 3 h daily for 9 days of 3 ATA oxygen. A second group (II) was given 3 ATA compressed air on the same schedule, and a third (III), a control, was given the same handling conditions only. Collagen and elastin which amounted to 10.45 and 4.62 mg, respectively, per 100 mg dry defatted parenchymal tissue was labeled with [14C]proline injected ip. Connective tissue protein turnover was estimated by labeling half of each group before exposure (a); effects on biosynthesis were determined by labeling the other half postexposure (b). No differences in hydroxyproline specific activity of collagen fractions or elastin were found with respect to either biosynthesis or turnover. Alveolar wall length-tension measurements were not changed. Since exposures were in excess of those used for treatment of gas gangrene, ischemic burns or wound healing, these results suggest that the metabolism of lung connective tissue is unaffected by the short-term exposure to hyperbaric oxygen.