Effects of cigarette smoking with different tar content on erythrocyte oxidant/antioxidant status.

In this study, the effects of cigarettes with differing tar content on erythrocyte oxidant/antioxidant status was investigated. Malondialdehyde (MDA) as an indicator of oxidant status and superoxide radical scavenger activity (SSA) as an indicator of antioxidant status were measured in erythrocytes from 20 smokers and 10 non-smoker controls. Ten of the 20 smoking subjects smoked five cigarettes with full flavour low tar (FFLT with 12 mg tar) and the others smoked five cigarettes with full flavour high tar (FF with 23 mg tar) over 1 hour. Initial blood samples from both groups at fasting, followed by further samples from smokers at 1.5 hours and 3 hours after smoking. Initial erythrocyte MDA level and SSA activity were found to be higher in the smoking groups compared to non-smokers. Furthermore, both parameters were significantly higher at the 1.5-hour and 3-hour erythrocyte samples when compared to initial values in the FFLT group. However, there were no statistically significant differences between SSA values established at different times in FF group. Results suggest that smoking causes oxidant load in the erythrocytes. Although a compensatory mechanism (i.e. increased SSA activities) develops in the FFLT group after smoking, this cannot prevent peroxidation reactions (i.e. increased MDA levels) in the erythrocytes. As to the types of cigarettes, both seem to have oxidant potential, but oxidation degree in the FFLT group is higher than that of FF group. These results suggest that antioxidant supplementation to smokers might be beneficial to decrease cellular oxidation damages.

The effects of cyclosporine on antioxidant enzyme activities and malondialdehyde levels in rabbit hepatic tissues.

Possible molecular mechanisms leading to cyclosporine-induced hepatotoxicity has not been cleared yet. Therefore, investigation of antioxidant status of hepatic tissues exposed to cyclosporine A (CsA) and of free radical involvement in the CsA-induced hepatotoxicity seems of importance. For this aim, 20 rabbits were used in the study. In each group (control, CsA, CsA plus vitamin and, vitamin only) there were 5 animals. CsA was given orally (25 mg/kg/day) for 10 days. Vitamins E (100 mg/kg/ day) and C (200 mg/kg/day) combination was injected intramuscularly. After 10th day, animals were killed, and livers were prepared for the enzymatic assays. Activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) and, malondialdehyde (MDA) levels were determined in the supernatant fractions. Lowered SOD, unchanged GSH-Px and, increased CAT activities and MDA levels were detected in hepatic tissues of rabbits treated with CsA as compared with controls. In the CsA plus vitamin group, SOD activity was found to be higher, GSH-Px and CAT activities unchanged and MDA levels lower than the CsA group. In the vitamin-treated group, all of the enzyme activities were higher than the controls but MDA levels were unchanged. Correlation analysis revealed some significant differences between the groups. Results suggest that cyclosporine impairs the antioxidant defense system and thus, leads to oxidant stress and peroxidation in rabbit hepatic tissues. It has been established that this process can be prevented by antioxidant vitamin supplementation.