The impact of ovarian stimulation on mouse endometrium: a morphometrical study

Background: The preparation of endometrium for embryo reception is dependent on the ovarian hormones, which are affected by ovarian hyperstimulation procedure. Objective: The aim of this study was to evaluate the changes in morphometrical indices of endometrium by the daily injection of progesterone after mouse ovarian induction. Materials and Methods: Adult virgin female mice were selected and divided into control and experimental groups. Experimental groups were superovulated using human menopasual gonadotropic hormone (HMG), and human chorionic gonadotropic hormone (HCG), then they, were subdivided into two groups, which one group was also injected daily by progesterone. All control and hyperstimulated groups were rendered pseudopregnant by cervical stimulation. Three and four days after the HCG injection, the samples of uterine horns were aparted and processed for light microscopic studies. Results: Our results showed that in the progesterone-injected group, the height of surface and glandular epithelium was decreased on day three (17.6±3.55, 10.02±2.6) and day four (16.9±4.24, 1.6±0.84) respectively, and it had low columnar morphology in comparison with the hyperstimulated and control groups. Also the intercellular spaces of stroma in progesterone-injected group were narrower than these in the other groups. Conclusion: Ovarian hyperstimulation followed by progesterone injection alter the morphometrical indices of surface and glandular epithelium of endometrium, which could affect on its receptivity.