[Effects of electroacupuncture pretreatment on ovarian function and expression of VEGF in rats with ovulation induction].

OBJECTIVE: To explore the protective effect of electroacupuncture (EA) pretreatment on ovarian function in rats with ovulation induction.

METHODS: Thirty SD female rats were numbered according to random number table. According to vaginal smear method, rats of estrus were divided into a normal group (10 rats) and cohabitated with male SD rats with the proportion of 1:1. With computer-generated random number, the remaining rats were divided into a model group and an EA group, 10 rats in each one. The model of superovulation was established with pregnant mare serum gonadotropin (PMSG) and human chorionic gonadotropin (HCG) in the model group and EA group. Before model establishment and cohabitation, rats in the EA group were treated with EA at "Guanyuan (CV 4)" and "Sanyinjiao (SP 6)", once for 15 min, for consecutive 7 days. Rats in the normal group and model group received no further treatment. The third day 23:00 pm after cohabitation, blood samples in three groups were collected to test the level of estradiol (E₂) and progesterone (P). After the rats were sacrificed, the HE staining method was applied to observe the morphological changes of ovarian tissue; the immunohistochemical method was applied to measure the expression of vascular endothelial growth factor (VEGF) and its receptor VEGFR-2; the real-time quantitative PCR technique was applied to measure the gene expression of VEGF and VEGFR-2.

RESULTS: The number of ovarian follicle in the EA group was higher than that in the model group and normal group (all P < 0.05); the ratio of corpus luteum size to ovarian size in the EA group was lower than that in the model group (P < 0.01). The ratio of plasma estradiol to progesterone in the EA group tended to be normal group (P < 0.05) and lower than that in the model group (P < 0.01). The protein expression of VEGF and VEGFR-2 in lutein granulosa cell and follicular fluid in the EA group was lower than that in the model group (P < 0.05); gene level of VEGF and VEGFR-2 in ovarian tissue in the EA group was lower than that in the model group (P < 0.05, P < 0.01).

CONCLUSION: EA pretreatment has certain protective effect on ovarian function in rats with ovulation induction, which is likely to be related to regulation of VEGF and its receptor.