The nitroxide tempol has similar antioxidant effects as physiological levels of 17beta-oestradiol in reversing ovariectomy-induced oxidative stress in mice liver and kidney.

OBJECTIVE: Oestrogen defciency increases oxidative stress postmenopause, while tempol is an intracellular radical scavenger that interferes with the formation or effects of many radicals. We aimed to investigate the effects of oestrogen and tempol on oxidative stress parameters in the kidney and liver of ovariectomized mice.

MATERIAL AND METHODS: Forty 8-week-old female Bald/c mice were divided into five groups: sham-operated, ovariectomized mice without treatment, ovariectomized mice treated with tempol, ovariectomized mice treated with 17beta-oestradiol and ovariectomized mice treated with 17beta-oestradiol and tempol. Oxidative stress in liver and kidney tissues was investigated by measuring 2-thiobarbituric acid reactive substances (TBA-RS), reduced glutathione, myeloperoxidase, superoxide dismutase and catalase levels.

RESULTS: TBA-RS levels were increased and reduced glutathione, myeloperoxidase, superoxide dismutase levels were decreased in the tissues of ovariectomized mice. This effect of ovariectomy on oxidative stress parameters was opposed significantly by the administration of tempol and 17beta-oestradiol either alone or in combination. Ovariectomy reduced the kidney catalase levels, but the effect was not statistically significant (p>0.05). On the other hand, catalase levels were elevated significantly in all treatment groups compared to those of the ovariectomized group (p<0.05).

CONCLUSION: These study findings demonstrate that tempol significantly opposes the oxidative stress generated by ovariectomy. This effect, which is evident in remote tissues such as liver and kidney, is comparable to that of physiological levels of oestradiol.