Abstract
Rats were exposed to 100% oxygen at 3 ATA for two hours a day. On the second, third, seventh or fourteenth day, alveolar macrophages（AMP）were collected by bronchoalveolar lavage.
Immunological functions of alveolar macrophages were evaluated by chemiluminescence and chemotaxis. Chemiluminescence, which indicates the production of active oxygen by macrophages, increased significantly after three, seven and fourteen days exposure to OHP. Chemotaxis increased also but not significantly after two, three and seven days exposure.
These results indicate that the OHP（100% Oxygen, 3 ATA, 2 hours）enhanced the immunological activity of rat AMP. The present findings imply that the activation of AMP due to repeated OHP causes alveoli damages.
