The influence of normobaric hyperoxia on hydroxyproline content and collagenase and elastase activities in rat lung

The influence of 12, 24 and 48 hrs of normobaric hyperoxia on hydroxyproline content and both collagenase and elastase activities in rat lung was investigated. The rise in hydroxyproline level in lung after only 24 hrs of hyperoxia was observed. In bronchoalveolar lavage, however, the level of this amino acid remains unchanged during the whole time of the experiment. Collagenase activity decreased significantly after 12 hrs of hyperoxia, and then decreased gradually. Elastase activity was diminished after 48 hrs of hyperoxia. It is suggested that breathing with pure oxygen induce changes in collagenase activity long before the changes in elastase activity or hydroxyproline content.