Effects of estrogen, estrogen/progesteron combination and genistein treatments on oxidant/antioxidant status in the brain of ovariectomized rats.

INTRODUCTION The aim of this study was to investigate the antioxidative effects of estradiol (E), E plus progesteron (P) combination (E/P) and genistein (G) treatment in the brain of ovariectomized (OVX) rats. MATERIALS AND METHODS Adult female Sprague-Dawley rats were divided into five groups, with each group including ten rats. Rats were anesthetized and bilateral ovariectomy was performed under general anaesthesia in all groups except for the sham operation group. Groups included: Sham-operated, control (OVX), estrogen treated group (OVX+ E), E/P combination group (OVX+E/P) and G treated group (OVX+G). Treatments were applied for 8 weeks. The total anti-oxidant status (TAS), total oxidant status (TOS), nitric oxide level (NO), glutathione peroxidase activity (GSH-Px) and oxidative stress index (OSI) were analysed in the brain tissue of rats from each treatment category. RESULTS Ovariectomy lead to an increase in brain TOS and OSI levels compared to the sham group (p < 0.05). Also, ovariectomy resulted in a decrease in brain TAS levels compared to the sham group that approached statistical significance (p = 0.078). Significant decreases in TOS, OSI, GSH-Px and a significant increases in TAS and NO levels were observed in the E-treatment group compared to the control group (p < 0.001). The E/P combination group exhibited a significantly decreased TOS and OSI and significantly increased TAS and NO levels relative to the control group (p < 0.05). Genistein treatment resulted in a significant decrease in TOS and OSI compared to the control group (p < 0.05). CONCLUSIONS Oxidative stress markers increase in the brain tissue of OVX rats. Conversely, estradiol, E/P and G supplementation decreases oxidative stress markers and increases antioxidant activity. Using G may prevent neural pathologies result in menopause-related oxidative stress.