Influence of estradiol on oxidative stress in the castrated rat uterus

We set out to study how the concentration of estradiol influences oxidative stress (malondialdehyde) and the superoxide dismutase and catalase antioxidant systems in the castrated female Wistar rat uterus.

We used 28 castrated female Wistar rats: 7 were left to evolve freely and the rest were divided into three groups of 7 animals receiving respective doses of 4, 8, and 16 microg/day of estradiol (E2) for 15 days. At the end of the study period, we determined the plasma concentrations of E2 and the concentrations of malondialdehyde (MDA) and superoxide dismutase and catalase activities in the uterus.

There was a significant correlation (P < 0.000028) between the uterine malondialdehyde levels and the logarithm (base 10) of the plasma E2 concentrations and also between malondialdehyde and the uterine catalase activity (P < 0.002). The regression plane that best fitted the correlation among the three variables was MDA = 10.21 + 12.88 x Log [E2] - 0.49 x catalase activity. We found no significant relationships with the superoxide dismutase activity.

There was a linear correlation between the base-10 logarithm of the estradiol plasma concentration and the phenomenon of uterine lipid peroxidation as measured by the MDA concentration in the uterus. This phenomenon was in part modulated by the inverse linear relationship between the antioxidant activity of the uterine catalase and the concentration of uterine MDA.