Effect of Mild Chronic Hyperbaric Pressure on Blood Antioxidant Levels Among Jordanian Smoker and Non- Smoker Males

Objective: Hyperbaric oxygen treatment and cigarette smoking are known to increase oxidative stress via the production of reactive oxygen species. Jordan, having different altitudes, offers an ideal geographical site to study the effect of mild chronic hyperbaric pressure (mHB), smoking and their combination on the level of antioxidants in humans. Methods: The levels of the antioxidants, glutathione in the whole blood and the erythrocyte antioxidant enzymes, were assessed in non-smoker and smoker male subjects living in the Dead Sea area in theJordan Valley which represents Earth s lowest point on land (423 m below sea level) and compared with male subjects living in the Amman area (766 m above sea level). Results: It was found that chronic mHB caused a significant increase in the levels of glutathione andglutathione peroxidase (~ 35% to 50%) and catalase (up to 20%) in smokers and non-smokers but resulted in a decrease in glutathione reductase (~ 25%) in both groups. However, smoking habit did not affect the level of antioxidants except for a slight change in a few cases. Conclusions: It is concluded that tolerance to mild chronic hyperbaric atmosphere involved induction ofthe antioxidants glutathione, glutathione peroxidase and catalase. In addition, the increased level of GSH may provide further protection to peripheral cells from any damage by the resulting mild increase in tissue O2 concentration in the subjects living under chronic mHB. Meanwhile, our results suggest that smoking appears to have little or no effect on the level of antioxidants in the blood.