Objective To observe the effect of transcutaneuos acupoint electrostimulation(TAES)on ovarian serum sex hormone levels and ovarian follicle granular cell aromatase cytochrome P 450(P 450arom)protein and follicle theca cell cytochrome P 450 17α-hydroxylase/c 17-20 lyase cytochrome P 450(P 450c17α)protein expression in polycystic ovary syndrome(PCOS)rats

so as to explore its mechanisms underlying improvement of PCOS.Methods Forty SD rats were randomly divided into four groups:normal control

model

medication and TAES(10rats/group).The PCOS model was established by giving(gavage)the animals with letrozole solution(1.0mg/kg

once daily for 21 consecutive days).Rats of the medication group were treated with Clomiphene(1mg/kg)once daily for 7days

and those of the TAES group were treated with electrical stimulation(2Hz

3mA)of"Guanyuan"(CV 4)and"Sanyinjiao"(SP 6)areas for 30 min

once daily for 7consecutive days.The rats body weight and bilateral ovarian weight were detected

and the ovarian structure and follicular development degree were observed under light microscope after H.E.stain

and the serum testosterone(T)

estradiol(E2)

luteotrophic hormone(LH)and folliclestimulating hormone(FSH)contents were detected using radioimmunoassay.The expression of ovarian P 450arom(for production of estrogen)protein and P 450c17α(for production of androgen)protein was detected by using immunohistochemical stain and Western blot

respectively.Results The body weight

bilateral ovary weight

serum T and LH contents

and ratio of LH/FSH

and ovarian P 450c17αimmunoactivity and protein expression levels in the model group were all significantly increased compared with the normal control group(P<0.01)

and the levels of serum E2 and ovarian P 450 arom immunoactivity and protein expression were significantly decreased after modeling(P<0.01).Following the treatment

the increased body weight

ovary weight

serum T and LH contents

ratio of LH/FSH

and ovarian P 450c17αimmunoactivity and protein expression levels

and the decreased ovarian P 450 arom immunoactivity and protein expression levels were reversed in the TAES group(P<0.01

P<0.05)rather than in the medication group

except serum T and ratio of LH/FSH in the medication group.No significant differences were found between the medication and TAES groups in the serum T and ratio of LH/FSH(P>0.05).In addition

the increased vesicular follicle number

the decreased corepus luteum number and the thickness of granular cell layer were markedly improved in the TAES group.Conclusion TAES intervention can reduce both body weight and ovarian weight and regulate the levels of serum sex hormones and ovarian P 450c17αand P 450 arom protein expression levels in PCOS rats

which may contribute to its effect in improving PCOS.