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Objective To investigate the effects of estrogen on extracellular signal-regulated kinase-1/2(ERK1/2) phosphorylation levels in hippocampal CA4 region of ovariectomized rats. Methods Experimental female Wistar rats were randomly divided into three groups: intact (INT) group, ovariectomized (OVX) group, and OVX+estrogen (1 mg/kg, weekly) group. Radioimmunoassay (RIA) was used to measure the estrogen content in plasma, and the levels of ERK1/2 phosphorylation were measured with immunohistochemistry. Results Compared with the control animals, the plasma estrogen level was significantly lower in OVX group (P＜0.001). However, the plasma estrogen level was higher in the OVX+estrogen group than that of the OVX group (P＜0.001). Immunohistochemical staining showed that the phospho-ERK1/2 (p-ERK1/2) substances were present in the nucleus and cytosol of neurons. Compared with the control group, immunostaining positive cells markedly decreased in OVX group, with light nucleus and cytosol staining in the hippocampal CA4 region (P＜0.001). The phospho-ERK1/2 positive neurons increased more obviously in OVX+estrogen group than in the OVX group (P＜0.001). Conclusion Estrogen can increase ERK1/2 phosphorylation levels in hippocampi of aging female rats, which suggests that the ERK signal transduction pathway may be regulated by estrogen during the process of aging.
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@#Objective To investigate the effects of estrogen on brain derived neurotrophic factor (BDNF) and neuropeptide Y (NPY) levels in cerebellar cortex of ovariectomized rats. Methods 24 female Wistar rats were randomly divided into three groups: intact (INT) group, ovariectomized (OVX) group, and OVX+estrogen 0.5 mg/kg every day group (E group). Radioimmunoassay (RIA) was used to measure the estrogen content in plasma, and the levels of BDNF and NPY were measured with Immunohistochemistry. Results Compared with the INT group, the plasma estrogen level significantly reduced in OVX group (P<0.001). However, the plasma estrogen level was higher in the E group than that in the OVX group (P<0.001). The BDNF and NPY presented in the Purkinje cell layer,and BDNF also distributed in the molecular layer and granular layer. Compared with that in the INT group, BDNF and NPY positive cells markedly decreased in OVX group, with slight cytosol staining in the cerebellar cortex (P<0.001). The BDNF and NPY positive neurons increased in E group compared with that in the OVX group (P<0.001). Conclusion Estrogen can increase the BDNF and NPY levels in cerebellar cortex of female rats, which may protect the structure and function of cerebellar neurons.
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@#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.