OBJECTIVETo explore the effects of electroacupuncture (EA) at "Zhongliao" (BL 33) and "Tianshu" (ST 25) on ovarian function in rats with premature ovarian insufficiency (POI).

METHODSA total of 48 SD female rats with regular estrus were divided into a blank group (=8), a model group (=10), an EA group (=10), a binding group (=10) and a tamoxifen (TAM) group (=10). The rats in the model group, EA group, binding group and TAM group were all treated with intraperitoneal injection of 4-vinylcyclohexene diepoxide (VCD, 160 mg/kg) for 15 consecutive days to establish the model of POI; the rats in the blank group were treated with normal diet. After the model was established successfully, the rats in the EA group were treated with EA at "Zhongliao" (BL 33) and "Tianshu" (ST 25) with continuous wave (1 to 3 Hz, 0.1 to 1 mA) for 20 minutes, once a day (five times a week) for the first two weeks and once every other day (three times a week) for the following two weeks. The rats in the TAM group were treated with subcutaneous injection of tamoxifen (1mg/kg), once a day (five times a week) for the first two weeks and once every other day (three times a week) for the following two weeks. The rats in the binding group were bound by a small sack as the EA group. The rats in the blank group and the model group were treated with normal diet. After four weeks, the sexual gland weight and index were tested in each group; the ELISA method was applied to test the level of anti-mllerian hormone (AMH) and inhibin B; the morphology of ovary was observed; the number of primordial follicles, primary follicle, antral follicle and atretic follicle was counted; the expression of insulin-like growth factor-1 (IGF-1) and insulin-like growth factor-1 receptor (IGF-1R) were measured.

RESULTS(1) Compared with the blank group, the ovary weight, ovary index, uterus weight and uterus index were significantly decreased after treatment in the model group, EA group, binding group and TAM group (all <0.01); but the differences between the model group and the EA group, binding group, TAM group were not significant (all >0.05). (2) Compared with the blank group, the levels of serum AMH, inhibin B and E were significantly reduced; the levels of FSH and LH were significantly increased in the model group; EA group, binding group and TAM group (all <0.01). Compared with the model group, the levels of serum AMH, inhibin B and E were significantly increased, the level of FSH and LH were significantly reduced in the EA group and TAM group (all <0.01). (3) Compared with the blank group, in the model group, EA group, binding group and TAM group the ovary was dark red and pale, surrounded by particle or not; the morphology was small and atrophic; the primordial follicles was reduced even vanished; the structure of primary follicle was damaged and loosely arranged; the mature follicle was few; the atretic follicle and interstitial gland were increased. (4) Compared with the blank group, the expressions of IGF-1 mRNA and IGF-1R mRNA were increased in the model group (all <0.01); compared with the blank group, the expression of IGF-1 mRNA was increased in the binding group (<0.05), but that of IGF-1R mRNA was not significantly different (>0.05); compared with the model group, the expression of IGF-1 mRNA was not significantly different in the EA group, binding group and TAM group (all >0.05), but that of IGF-1R mRNA was reduced (<0.05, <0.01).

CONCLUSIONEA at "Zhongliao" (BL 33) and "Tianshu" (ST 25) has improvement effect on ovarian function in rats with VCD-induced POI, which is likely to be related to regulating the IGF-1R mRNA expression to improve the IGF-1/ IGF-1R axis.