ABSTRACT
BACKGROUND: It has been suggested that diabetic patients are under high oxidative stress and plasma MDA concentration is a reliable marker for oxidative stress. However, some studies showed that plasma MDA is not a good marker for oxidative stress. Reeently, the total radical-trapping antioxidant parameter (TRAPc) has been proposed as a marker for the overall antioxidant property of plasma samples. Therefore, in this study, we tried to evaluate whether MDA and TRAPc are reliable markers of the oxidative stress-antioxidant system or not. METHODS: The plasma samples from 67 type 2 diabetic patients and 31 normal subjects were collected. The plasma MDA, protein-bound SH groups, uric acid and vitamin C were determined by fluorophotometry or spectrophotometry. Plasma vitamin E concentration was analyzed by HPLC. Calculated TRAP (TRAPc) were determined by the proposed calculation methods. RESULTS: 1. Diabetic patients had significantly lower TRAPc, compared with normal subjects. 2. SH groups, uric acid, vitamin C and vitamin E were not different between the two groups. 3. MDA and MDA/TG were significantly higher in diabetic subjects. CONCLUSION: From the results of this study, TRAPc seems to be a reliable parameter of overall plasma antioxidant system and the plasma MDA may be used as a marker of oxidative stress, but further long-term logitudinal studies are needed.