Objective To observe the effect of electroacupuncture(EA)intervention combined with clomiphene critate(CC)on the blastocyst implantation and pregnancy rate and expression of insulin receptor(INSR)and insulin receptor substrate 1(IRS 1)proteins in the endometrium in rats with polycystic ovary syndrome(PCOS)

so as to reveal its mechanisms underlying improvement of PCOS.Methods One hundred and twenty-five female SD rats were randomly divided into normal control

PCOS model

medication(CC)

EA and EA+CC groups(n=25in each group

15 for checking blastocyst implantation

and 10 for Western blot).The PCOS model was established by subcutaneous injection of Dehydroepiandrosterone(DHEA)and fed with high-fat diet.Rats of the normal control group were treated by subcutaneous injection of sesame oil and fed with the normal forage.EA stimulation was applied to"Zhongwan"(CV 12)

"Guanyuan"(CV 4)and bilateral"Tianshu"(ST 25)for 30 min

3times a week

5weeks altogether.Rats of the CC and EA+CC groups were fed with CC(100mg·kg-1·d-1)for 2days after regular restriction(30min

3times a week

5weeks altogether).The pregnancy was determined by vaginal smear tests and the number of blastocyst implantation determined by examination of the uterus after execution.The expression of INSR and IRS 1proteins in the endometrium was detected by Western blot.Results The pregnancy rate and the number of blastocyst implantation were significantly lower in the model group than in the normal control group(P<0.05)

and remarkably increased after EA and EA+CC interventions(P<0.05).The effects of EA+CC were obviously superior to those of simple EA and simple medication in raising the pregnancy rate and the number of blastocyst implantation(P<0.05).No significant differences were found between the EA and CC groups in the pregnancy rate and the number of blastocyst implantation(P>0.05).The relative expression levels of both INSR and IRS 1proteins were markedly lower in the model group than in the normal control group(P<0.05)

and significantly higher in both EA and EA+CC groups than in the model group(P<0.05).No significant differences were found between the model and the CC groups and between the EA and EA+CC groups in the expression levels of INSR and IRS 1 proteins(P>0.05).Conclusion EA intervention can improve pregnancy rate and the number of blastocyst implantation in PCOS rats

which may be related to its effects in up-regulating the expression of INSR and IRS 1proteins in the endometrium.