Objective To investigate the effect of joint administration of electroacupuncture(EA) and bone marrow mesenchymal stem cells(BMMSC) on the expression of estrogen receptor(ER) and progesterone receptor(PR) in thin endometrium rats

so as to explore its mechanisms underlying improvement of conception rate. Methods Forty female SD rats were divided into control

model

BMMSC and EA+BMMSC groups. The thin endometrium model was established by intrauterine infusion of 95% ethanol and saline. EA(1 mA

2 Hz/15 Hz) was applied to "Guanyuan"(CV4)

unilateral "Zigong"(EX-CA1) and unila-teral "Sanyinjiao"(SP6) for 15 min

once daily for 10 d. Rats of the BMMSC and EA+BMMSC groups received injection of BMMSC suspension through caudal vein on the day of modeling

the 3

(rd)

day after surgery

and the 2(rd) day after surgery

and the 2

(nd)

and the 3(nd) and the 3

(rd)

estrus phases

respectively. Changes of body weight and estrus phase were continuously recorded. After three estrus cycles

uterine specimens were taken and the uterine coefficient was calculated. The immunoactivity of KI67(an antigen for cell proliferation) was detected by immunohistochemistry

and the expression of ER and PR was detected by Western blot. Results Compared with the control group

the uterine coefficient

and expression of endometrium ER and PR proteins were significantly decreased in the model group(P

<

0.001

P

<

0.01). In Comparison with the model group

the uterine coefficient

immunoactivity of KI67

and expression of ER and PR proteins were significantly increased in both BMMSC and EA+BMMSC groups(P

<

0.000 1

P

<

0.001

P

<

0.01). The expression level of PR in the EA+BMMSC group was notably higher than that in the BMMSC group(P

<

0.05)

but no significant difference was found between the BMMSC and EA+BMMSC groups in the levels of uterine coefficient and ER expression(P

>

0.05). Conclusion EA combined with BMMSC injection has a positive effect in promoting the proliferation of endometrium cells in rats with thin endometrium

which may be related to its effect in up-regulating the expression of ER and PR proteins.