The Morphological Expression of Endometrial Pinopodes During Implantation in Mice After Ovarian Stimulation and Progesterone Injection

Introduction: The aim of this study was to evaluate the expression of pinopodes as animplantation marker after ovarian hyper stimulation and progesterone injection using scanningelectron microscopic studies. Material and Methods: Three groups of NMRI adult female mice were used in the experiment. The control group (Group A) were untreated pseudopregnant mice. Group B mice were made pseudopregnant after super ovulation treatment with hMG and hCG. Group C micewere treated the same as Group B and then received progesterone daily from day 1 of pseudopregnancy. Animals were sacrificed by cervical dislocation 3.5 and 4.5 days after hCG injection. Tissues were obtained from the middle 1/3 part of uterine horns and processed for scanning electron microscopic studies. Results: In the control group there were some pinopodes at 3.5 days of pseudopregnancy and the apical surface of all cells expressed these projections on day four. In the hyperstimulated group without progesterone injection no pinopodes were seen 3.5 days after hCG injection and some appeared on day 4. In the hyper stimulated and progesterone-injected group well developed pinopodes were expressed 3.5 days after stimulation and they became much smaller on day 4 after hCG injection. Conclusion: The results showed that the life span of pinopodes is short and changeable during hyper stimulation and that progesterone causes premature expression of the pinopodes, suggesting that the implantation after ovarian stimulation might depend upon the timing of the pinopode expression.