OBJECTIVE  To explore the effect of electroacupuncture on ovarian reserve function and Th1/Th2 immune balance in DOR rats based on the preventive treatment theory.

  METHODS  A total of 27 female SPF Sprague-Dawley rats with normal estrus cycle were randomly divided into control group, DOR group, and electroacupuncture group, with 9 rats in each group. The DOR group and the electroacupuncture group were treated with intragastric administration of tripterygium glycosides(TGs) tablet suspension at a dose of 50 mg·kg^-1·d^-1 for 14 days to establish the DOR models. An equal volume of normal saline was given to the control group once a day for 14 days. One hour after intragastric administration, rats in the electroacupuncture group had a daily 10-minute electroacupuncture treatment at bilateral "Shenshu" (BL23) or "Guanyuan" (CV4) and "Zhongwan" (CV12). The two groups of acupoints were alternated every other day. The electroacupuncture parameters were as follows: 2/100 Hz, 1.0 mA. Vaginal smears were obtained every day starting the first day of intervention to monitor the estrus cycle of the rats. After the intervention, HE staining was used to observe the histological morphology of ovaries; the level of estradiol (E₂), follicle-stimulating hormone (FSH), interleukin-4 (IL-4) and interferon-γ (IFN-γ) were measured through ELISA kits; the expression of T-bet and GATA3 mRNA was detected by qPCR; the protein levels of T-bet and GATA3 in ovarian tissue were detected by immunohistochemistry and Western blot; the ratio of Th1 and Th2 cells in the spleen was detected by flow cytometry.

  RESULTS  Compared with the control group, the number of primordial follicles in the DOR group decreased (P < 0.05), and atretic follicles increased (P < 0.01); both the ovarian index and spleen index were reduced in the DOR group (P < 0.01); serum E₂ and IL-4 levels decreased (P < 0.05), while the levels of FSH and IFN-γ increased in the DOR group (P < 0.05); GATA3 protein and mRNA expression lessened (P < 0.05, P < 0.01), while T-bet protein and mRNA expression were upregulated in ovarian tissues (P < 0.05); the T-bet/GATA3 ratio was elevated (P < 0.05); the proportion of Th1 cells as well as Th1/Th2 ratio increased (P < 0.01), and the proportion of Th2 cells decreased (P < 0.05). In comparison with DOR group, the number of primordial follicles in the electroacupuncture group increased notably, which was accompanied by decreased atretic follicles (P < 0.01); the ovarian index and spleen index increased (P < 0.01); the levels of E₂ and IL-4 both increased(P < 0.05, P < 0.01), while FSH and IFN-γ concentrations decreased in DOR group (P < 0.01); GATA3 protein and mRNA were expressed higher in ovarian tissues (P < 0.05), while the expression of T-bet protein and mRNA was downregulated (P < 0.05, P < 0.01); the T-bet/GATA3 ratio is reduced (P < 0.01); the proportion of Th1 cells alone with Th1/Th2 ratio decreased (P < 0.05, P < 0.01), and the proportion of Th2 cells was higher than that in DOR group (P < 0.05).

  CONCLUSION  Electroacupuncture has a protective effect on ovarian reserve in DOR rats, and its mechanism may be related to the regulation of Th1/Th2 immune balance.