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Updated: Aug 19, 2026
Ovariectomy and 17β-estradiol Replacement in Rats and Mice: A Visual Demonstration
Published on: June 7, 2012
Influence of estradiol and gestagens on oxidative stress in the rat uterus
M A Gómez-Zubeldia1, S Corrales, J Arbués
1Department of Nursing, School of Medicine, University of Extremadura, Avenida Elvas s/n, 06071 Badajoz, Spain.
Objective:
We studied the effect of ovariectomy, estradiol (E2), and E2 + medroxyprogesterone (MPA) on the Wistar rat uterus.
Methods:
We used 15 adult female rats. The study was divided into the following four stages: (a) extirpation of the upper half of the left hemi-uterus (basal state) and ovariectomy; (b) animals were maintained for 15 days without treatment, performance of a new laparotomy, and extirpation of the remaining left hemi-uterus (OVX state); (c) beginning of E2 replacement therapy (ERT) (8 microg/day) for 15 days, followed by extirpation of the upper half of the right hemi-uterus (ERT state); and (d) the administration of E2 was continued, and oral treatment with MPA was begun (20 microg/day) to last for a further 15 days. At the end of the combined hormone replacement therapy (HRT) the remaining right hemi-uterus was extirpated (HRT state). At the end of each intervention, the plasma concentrations of E2 and PRG were measured.
Results And Discussion:
The ovariectomy significantly reduced the malonaldehyde (MDA) levels (P < 0.0008) and catalase activity (P < 0.0006). The ERT very significantly (P < 0.0033) raised the catalase and MDA levels; these significance levels were maintained after the Bonferroni method was applied (overall error 5%). The HRT reduced the levels of MDA and catalase, but not significantly after the Bonferroni test was applied.Conclusions. Uterine oxidative stress is increased by E2, resulting in a significant increase in MDA. This may be modulated in part by the catalase activity. Although it cannot be confirmed categorically, MPA seems to intervene by decreasing the said oxidative stress.
