[abstract] THE EFFECT OF HYPERBARIC OXYGEN ON ENDOGENOUS LEVELS OF SUPEROXIDE DISMUTASE AND CATALASE

Abstract

BACKGROUND: Superoxide dismutase (SOD) and cataclause (Cat) are enzymatic antioxidants important for protection of tissues from oxidative damage. These endogenous antioxidants have been shown to play a role in oxygen toxicity and their circulating levels may be related to oxidant stress from hyperbaric oxygen (HBO) exposure. METHODS: Rats were subject to HBO at pressures of either 2.0, 2.5, or 3.0 ATA 100percent oxygen for 60 minutes with 10 minutes each for compression and decompression. Exposures were daily for either 3 or 7 days. Upon completion of daily HBO, blood was withdrawn and analyzed for superoxide dismutase and catalase. RESULTS: At 2.0 ATA, continued HBO resulted in significantly increased (P less than 0.05 by ANOVA) SOD levels. Discontinuance of HBO resulted in significantly lower levels of SOD. With 3.0 ATA exposures there was some mortality of the animals but all other pressures pressures resulted in complete survival. Catalase was significantly altered in some of the treatments and remained high with higher pressures. CONCLUSION: In this study, hyperbaric oxygen treatments are shown to alter levels of endogenous antioxidants. This may have important implications in HBO clinical situations reguarding toxicity risks.