OBJECTIVETo explore the optimal time of acupuncture intervention in the assisted reproduction.

METHODSOne hundred and twenty female mice and 60 male mice were collected. 20 female mice were selected in the natural period group and the rest 100 female mice were prepared as the model of controlled ovarian hyperstimulation (COH). The model mice were randomized into a COH group, a down-regulation group, a gonadotropins (Gn) start group, an injection of human chorionic gonadotropin (HCG) group and an embryo culture group, 20 mice in each one. The donor mice and receptor mice were subdivided in each group, 10 mice in each subgroup. One week before the experiment, vas deferens ligature was done in 30 male mice and the other 30 male mice did not receive ligature. In the down-regulation group, the Gn start group, the HCG injection group and the embryo culture group, electroacupuncture (EA) was applied to "Guanyuan" (CV 4), "Zhongji" (CV 3) and "Sanyinjiao" (SP 6) at the time points accordingly. EA stimulation was in the condition of continuous wave, 2 Hz and 1 mA. No inter-vention was given in the natural period group and the COH group. On the day of HCG injection, the donor mice and the non-ligatured male mice were put in the same cage of each group. The fertilized ovum was collected with the date of fertilization marked and was fostered in the incubator. At the ratio of 1:1, the receptor mice and ligatured mice were put in the same cage in each group. The vaginal plug was examined in the next morning. The pseudopregnancy was marked with the date of plug observed. In the 68th hour of embryo culture, the embryo of the donor was shifted to the receptor on the same day when the plug was observed. The clinical pregnancy rate and embryo imbed site number were observed. RT-PCR assay was adopted to determine the expression of insulin-like growth factor-1 (IGF-1) mRNA in endometrium.

RESULTSIn the COH group, the pregnancy rate, average imbed site number and endometrial IGF-1 mRNA expression were all significantly lower than those in the natural period group (all<0.01). After EA treatment, in the Gn group, the HCG injection group and the embryo culture group, the pregnancy rates were higher significantly than those in the COH group (<0.05,<0.01). In the HCG injection group, the average imbed site number and IGF-1 mRNA expression were increased apparently as compared with those in the COH group (both<0.01), better than those in the Gn group and the embryo culture group (all<0.01).

CONCLUSIONSIn the treatment with acupuncture combined with IVF-ET for infertility, the intervention of acupuncture on the day of HCG injection is the optimal time point. It increases the secretion of endometrial IGF-1 so as to improve the clinical pregnancy rate, the mean imbed site number and the embryo implantation.