[Study on the changes of gonadotropin releasing hormone agonist in pinopodes].

Objective: To study the changes of gonadotropin releasing hormone agonist (GnRH-a) in pinopodes during luteal phase and to explore the possible mechanism of GnRH-a in luteal phase support of assisted reproductive technology (ART). Methods: Totally 40 primary infertility women who were treated with ART due to male factors were enrolled, according to the order of the group they were randomly divided into experimental group and control group. On the 7th day after ovulation, the experimental group received a subcutaneous injection of 0.1 mg of GnRH-a, while the control group received a subcutaneous injection of placebo only (0.9% saline 2 ml), 3 days later they came to the clinic again. Serum estradiol and progesterone levels were measured before and after treatment in each group. Pinopodes were collected for electron microscopic examination. Levels of ER and PR were detected by western blot. Results: (1) There was no significant difference between the experimental group and the control group in the estrogen level before and after the treatment (all P>0.05). The level of progesterone in the experimental group after treatment [(66.8±14.9) nmol/L] was significantly higher than that before treatment(P<0.05); also significantly higher than the same period of the control group (P<0.05). (2) There was no significant difference in the expression of ER protein in the experimental group before and after treatment (P>0.05). The expression of PR in the experimental group after treatment was significantly lower than that before treatment (P<0.05); also lower than the same period of the control group (P<0.05). (3) Expression amount of pinopodes in the experimental group after treatment was significantly higher than that before treatment [65% (13/20) versus 25% (5/20), P<0.05], and the development trend was more mature [the percentage of maturation:75% (15/20) versus 35% (7/20), P<0.05]. Expression amount of pinopodes after treatment and the percentage of maturation in the experimental group were significantly higher than those in the same period of control group (P<0.05). Conclusion: GnRH-a in luteal phase support may play a role through the corpus luteum, which may promote the secretion of progesterone, downregulation of PR expression, promote the growth of pinopodes, and improve the endometrial receptivity.