Abstract: Objective To determine the regulation of electroacupuncture(EA)at Zusanli acupoint for the expression of estrogen receptors mRNA in the brain of ovariectomized rats.MethodsFemale Wistar rats were randomly divided into 3 groups:intact group(INT),ovariectomized group(OVX),and ovariectomy and acupuncture group(OVX+EA).Radioimmunoassay(RIA)was used to measure the estradiol(E2)and testosterone(T)levels in plasma.The mRNA levels of estrogen receptor(ER)α and ERβ in the brain of rats were measured with RT-PCR.ResultsThe levels of endogenous estrogen increased significantly in OVX+EA rats compared with OVX rats(P<0.01),while the plasma T levels were lower in the OVX+EA group than those of the OVX group(P<0.01).Eelectroacupuncture can up-regulate ERα expression in the brain of ovariectomized rats(P<0.01).However,it was shown to have a down-regulatory effect on the levels of ERβ expression(P<0.01).ConclusionThere is an intimate relationship between the expressions of estrogen receptors mRNA and the endogenous hormone levels,such as E2 and T.Electroacupuncture can regulate the expression of estrogen receptors mRNA in the brain and the E2 and T levels in plasma of ovariectomized rats,which might,at least in part,explain the mechanisms of acupuncture adjusting the neuroendocrine system.

Key words: estrogen, sex hormone, estrogen receptors, electroacupuncture, ovariectomized rats