Gender-dependent variations in systemic biomarkers of oxidative protein, DNA, and lipid damage in aged rats

Abstract

Introduction. The effect of aging on plasma-protein, lipid and DNA oxidation is well documented. However, none of the studies specify the effect of gender. The purpose of this study is to clarify the ambiguity raised in preliminary reports as to gender dependency of oxidative damage in plasma.

Methods. In the current study, we investigated the relation between 8-hydroxy-2′-deoxyguanosine levels (8-OHdG), which is a measure of DNA oxidation and protein oxidation parameters such as protein carbonyl (PCO), total thiol (T-SH), and advanced oxidation protein products (AOPP). Our study also covered other oxidative stress parameters, such as lipid hydroperoxides (LHP), malondialdehyde (MDA), erythrocyte glutathione (GSH), superoxide dismutase (Cu-Zn SOD) and the catalase (CAT) activity in plasma of the male and female aged rats.

Results. 8-OHdG and MDA levels in male rats were significantly higher than those in the female group (p < 0.01 for both parameters). T-SH levels were found to be higher in female rats than in the male (p < 0.05). Plasma Cu-Zn SOD activities of male rats were significantly higher compared with those of the female rats (p < 0.05). On the other hand, PCO, AOPP, LHP, GSH levels, and CAT activity were not found to be different between genders.

Conclusions. We suggest that increased T-SH levels found in female rats may point to an adaptive reaction to oxidative damage, reflecting 8-OHdG and MDA overproduction. We are of the conviction that the increased 8-OHdG and MDA that we have determined in aged male rats may be a risk factor in the extent of oxidation in plasma.

Keywords:

• Aging
• plasma
• gender
• protein oxidation
• DNA oxidation
• lipid peroxidation

Acknowledgements

This work was supported in part by funding from a grant from the Research Fund of The University of Istanbul (UDP-4041/2009). The corresponding author is grateful to linguistic expert Mr. Erhan Tecimen for reading the manuscript and for improvements in the linguistic style.