EXPOSURE OF RATS TO HYPEROXIA - ALTERATION OF LAVAGATE PARAMETERS ANDMACROPHAGE FUNCTION

Exposure of rats to hyperoxia (100% oxygen for 64 h) resulted in strik ing alterations in the properties of samples obtained by bronchoalveol ar lavage. The yield of neutrophils, lymphocytes, and red blood cells was increased, while the number of harvested alveolar macrophages decr eased. The acellular lavage fluid level of protein was elevated, indic ating lung damage. However, acellular phospholipid levels were unchang ed. The ability of alveolar macrophages to produce reactive forms of o xygen in response to zymosan was significantly decreased by oxygen exp osure. This impaired function was not fully explained by a decrease in viability of these phagocytes. In contrast, stimulant-induced chemilu minescence was elevated after hyperoxia. This rise was not due to a ch ange in cellular antioxidant levels or to a discernible increase in ar achidonic acid metabolites. However, it was associated with increased cellular lipid peroxidation.