Objective To observe the effect of drug-paste separated moxibustion of"Mingmen"(GV 4)on the levels of serum estrogen(E2)and progesterone(P)and their endometrial receptor mRNA expression in rats with primary dysmenorrhea in order to investigate its mechanism underlying improvement of primary dysmenorrhea.Methods A total of 100female SD rats were randomized into control

model

medication

acupuncture and moxibustion groups

with 20rats in each group.Primary dysmenorrhea model was established by subcutaneous injection of Benzestrofol for 10days and intraperitoneal injection of Oxytocin for1d.Rats of the medication group were fed with extractum leonuri inspissatum(8g/100g)and those of the moxibustion group treated with drug-paste separated moxibustion at"Mingmen"(GV 4).For rats of the acupuncture group

a filiform needle was inserted into GV 4

manipulated for a while and retained for 30min.The treatment of the latter 3groups was conducted once daily for 7days.The rat's body-writhing latency and times during 30min were recorded.The contents of serum E2and P were detected by ELISA

and the expression of estrogen receptor(ER)mRNA and progesterone receptor(PR)mRNA in the endometrium was determined by quantitative real-time(RT)-PCR.Results ①The body-writhing latency was shorter and the writhing times were more in the model group than in the control group(P<0.01).Compared with the model group

the body-writhing latency was significantly increased and the writhing times were obviously decreased in the medication

acupuncture and moxibustion groups(P<0.01).There were no significant differences among the medication

acupuncture and moxibustion groups in the body-writhing latency(P>0.05)

but the body-writhing numbers of the acupuncture and moxibustion groups were markedly lower than that of the medication group(P<0.01).②Compared with the control group

serum E2content and endometrial ER mRNA expression level were significantly increased

and serum P content and endometrial PR mRNA level evidently decreased in the model group(P<0.01

P<0.05).In comparison with the model group

serum E2contents and endometrial ER mRNA expression levels were considerably down-regulated

and serum P contents and endometrial PR mRNA expression levels markedly up-regulated in the medication

acupuncture and moxibustion groups(P<0.01

P<0.05).The effects of the moxibustion group were significantly superior to those of the acupuncture and medication groups

and those of the acupuncture group were also significantly superior to those of the medication group in lowering E2and endometrial ER mRNA levels

and raising serum P and endometrial PR mRNA expression levels(P<0.01

P<0.05).Conclusion Drug-paste separated moxibustion of GV 4is effective in relieving pain in primary dysmenorrheal rats

which is probably associated with its effects in down-regulating serum E2content and endometrial ER mRNA expression

and up-regulating serum P and endometrial PR mRNA expression levels.