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Osteoporosis， as a systemic bone disease with high incidence rate and high disability rate， has become a research hotspot in recent years. The daidzein in soybean isoflavones can bind with estrogen receptors， simulating the prevention and treatment of osteoporosis with estrogen-like effect. Its mechanism of action includes promoting osteoblast formation and differentiation by activating the Wnt signaling pathway， increasing bone density， and improving bone tissue health； inhibiting osteoclast differentiation and slowing down bone resorption by reducing receptor activator of nuclear factors κB ligand/ osteoprotegerin ratio， downregulating the expression of macrophage colony-stimulating factor （M-CSF）； collaborating antioxidant and immune regulation to achieve the goal of preventing and treating osteoporosis. In addition， different doses of daidzein have different effects on bone density and osteoporosis， which may be related to factors such as study design， sample selection， and individual differences.
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Background Arsenic can enter the hypothalamus to induce estrogen effect and interfere with the function of the neuroendocrine system. The thyroid endocrine system (hypothalamic-pituitary-thyroid axis) is one of the main endocrine systems, and the mechanism of arsenic-induced thyroid endocrine toxicity is still unclear. Objective To investigate the effects of different arsenic exposure levels on estradiol (E2), hypothalamic thyrotropin-releasing hormone (TRH), and their receptor (ERα, ERβ, and TRHR) mRNAs in rats and the possible hypothalamic toxic pathway and mechanism. Methods Seventy Wister rats were randomly divided a control group (sterile water); low-, medium-, and high-dose arsenic exposure groups [0.8, 4.0, and 20.0 mg·kg−1 sodium arsenite (NaAsO2)]; estrogen receptor inhibitor (ICI182780) intervention + low-, medium-, and high-dose arsenic exposure groups; with 10 animals in each group, half male and half female. Rats in the arsenic exposure groups were exposed to NaAsO2 by drinking water for 19 weeks, and rats in the intervention groups were injected with 0.5 mg·kg−1 ICI182780 via tail vein at week 9, 3 times a week. The levels of E2 and TRH in serum of rats were detected by ELISA. The expression levels of estrogen receptor α (ERα), estrogen receptor β (ERβ), and TRH receptor (TRHR) mRNAs in hypothalamus of rats were detected by real-time PCR (RT-PCR). Results (1) E2 and its receptor mRNA: Compared with the control group, the serum E2 level of female rats was increased in the low-dose and the medium-dose arsenic exposure groups (P<0.05), and the serum E2 level of male rats was increased in the low-dose, the medium-dose, and the high-dose arsenic exposure groups (P<0.05), and the change of female E2 was greater than that of male rats. Compared with the control group, the relative expression levels of ERα mRNA and ERβ mRNA in female rats were increased in the low-dose, the medium-dose, and the high-dose arsenic exposure groups (P<0.05), so were the relative expression levels of ERα mRNA in male rats (P<0.05). (2) TRH and its receptor mRNA: Compared with the control group, the serum TRH level of female rats was increased in the high-dose arsenic group (P<0.05), the relative expression level of TRHR mRNA was increased in the low-dose, the medium-dose, and the high-dose arsenic exposure groups (P<0.05). Results (1) and results (2) suggested that females were more likely than males to have abnormal changes in E2, TRH, and related receptor genes after arsenic exposure. (3) Compared with female rats in the medium-high dose arsenic exposure group, the expressions of TRH and TRHR induced by arsenic exposure were inhibited after the intervention of ICI182780 (P<0.05), suggesting that arsenic in the hypothalamus may have toxic effects on TRH and TRHR by inducing estrogen-like effects. Conclusion Arsenic exposure can induce estrogen-like effects in the hypothalamus, interfere with thyroid function, and show dose-dependent and sex differences. E2 and TRH and their receptors may be the toxic pathway of arsenic-related estrogen-like effect.
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OBJECTIVE： To investigate estrogen-like effect of tetrahydroxy stilbene glucoside （TSG） and its effects on the expression of estrogen receptor （ER） in uterus of sexually immature mice. METHODS： Totally 60 sexually immature Kunming mice were randomly divided into normal group， positive control group （estradiol valerate， 0.18 mg/kg）， TSG low-dose and high-dose groups （50， 150 mg/kg）， TSG low-dose and high-dose groups+estradiol valerate groups （same dose as medication alone group）. Normal group was given constant volume of water intragastrically， and administration groups were given relevant medicine 0.2 mL/10 g， once morning and night， for consecutive 5 d. The uterus index and body weight increase of mice in each group were determined and calculated the next day after the last administration. The contents of serum estrogen （E2， LH， FSH） were determined by ELISA. HE staining was used to observe the morphology characteristics of uterus， and uterine tube diameter and endometrial thickness were detected. The expression of ER（ER-α and ER-β） in uterus was detected by immunohistochemical staining. RESULTS： The myometrium of the mice in normal group was parallel and compact， the epithelium of the uterus was columnar， and the expression of ER-α and ER-β was low. The uterine tube diameter， endometrium and epithelium of mice in each administration group increased， thickened or proliferated in varying degrees， and the expression of ER-α and ER-β changed. Compared with normal group， uterus indexes （positive control group， TSG high-dose group， TSG+estradiol valerate groups）， the increase of body weight （positive control group， TSG high-dose groups， TSG low-dose+estradiol valerate group）， uterine tube diameter and endometrial thickness （positive control group， TSG low-dose group， TSG+estradiol valerate groups）， the expression of ER-α （positive control group， TSG+estradiol valerate groups） and the expression of ER-β （postive control group， TSG high-dose+estradiol valerate group）were increased significantly， while serum contents of LH （positive control group， TSG high-dose group） and FSH （TSG low-dose+estradiol valerate group） were decreased significantly （P＜0.05 or P＜0.01）. The uterus index， uterine tube diameter， endometrial thickness and the expression in ER-α and ER-β of TSG+estradiol valerate groups， the increase of body weight and serum content of E2 in TSG low-dose+estradiol valerate group were significantly higher than same TSG dose alone groups （P＜0.05 or P＜0.01）. The uterus index， uterine tube diameter， endometrial thickness and the expression of ER-α and ER-β in TSG groups， uterine tube diameter and the expression of ER-β in TSG+estradiol valerate groups， body weight increase of mice in TSG low-dose group were significantly lower than positive control group， while serum content of LH in TSG+estradiol valerate groups were significantly higher than positive control group （P＜0.05 or P＜0.01）. CONCLUSIONS： TSG can increase uterus indexes and body weight of sexually immature mice to certain extent， regulate estrogen level， increase the diameter of uterine tube and endometrial thickness and up-regulate the expression of ER in the uterus， showing certain estrogen-like effect， which is weaker than that of estradiol valerate. Combined use of them may antagonize the effect of estradiol valerate.
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The study was designed to test the estrogen-like effects about allantoin. The activity of the allantoin was investigated by mouse uterine weight gain test and MCF-7 cell proliferation assay. The levels of E2, FSH and LH were also measured. ICI182,780, MPP, THC and G15 antagonnist assay and Western blot were adopted to explore the mechanism of allantoin. Allantoin increased the uterus index of premature female mice, the levels of E2 and FSH, and the expression of ERα and GPR30, compared with the control group. Allantoin also promoted the proliferation of MCF-7 cells. Co-incubation of MCF-7 cells with estrogen receptor blockers, ICI182,780, MPP and G15 abolished the inductive effect of the proliferation. These results suggest that allantoin has estrogenic activities, which are mainly mediated by ERα, GPR30.
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Genistin, a kind of soy isoflavones with estrogen-like effect, is one of the effective components of soybean isoflavone. Recently, many researches have shown that genistin possesses a variety of pharmacological activities, however, the summary of its pharmacological activity is not enough. This review mainly focuses on the progress in the estrogen-like effects, anti-tumor activity, improvement of the myocardial ischemia, anti-inflammation activity, the regulation of metabolic syndrome related diseases and other pharmacological activities of genistin, so as to provide reference for the future studies and applications of genistin and other soy isoflavones.
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Aim To investigate the effect of preventive administration of icariin on learning and memory abili-ties and brain mitochondrial oxidative stress in senes-cence-accelerated mouse prone8 ( SAMP8 ) . Methods The 6-month-old SAMP8 mice were randomly divid-ed into the SAMP8 model group, ICA groups (75, 150 mg · kg-1 ) , the positive Diethylstilbestrol ( DES ) group and estrogen receptor inhibitor ICI182780 com-bined with ICA (150 mg·kg-1 ) group, with 8 mice in each group. 8 same month old SAMR1 mice were selected as the normal control group. After oral admin-istration for 8 weeks, Morris water maze test and step-down passive test were used to investigate the effects of preventive administration of ICA on learning and mem-ory abilities in SAMP8 mice. Cerebral cortex mitochon-dria were isolated to determine the effect of preventive administration of ICA on the oxidative stress by detec-ting reactive oxygen species ( ROS) level, lipid perox-ides ( MDA ) content, glutathione GSH content and catalase ( CAT ) activity. Results Preventive treat-ment of ICA could significantly improve the abilities of place navigation and space exploration of SAMP8 mice, enhance their reflex ability in step-down passive test. ICA could also reduce the level of ROS and MDA content, increase GSH content in brain mitochondria of SAMP8 mice. CAT activity was not obviously changed. Compared with ICA high dose group, the learning and memory abilities of mice in ICA and estrogen receptor inhibitor ICI182780 co-administrated group were signif-icantly decreased. However,brain mitochondria oxida-tive stress was not changed obviously. Conclusion Preventive administration of icariin can significantly improve learning and memory abilities and brain mito-chondrial oxidative stress in SAMP8 mice. The mecha-nism of ICA improving learning and memory abilities may be related to its estrogen-like effect;while the ac-tion on brain mitochondrial oxidative stress may be in-dependent of estrogen receptor.
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Objective To investigate the estrogen-like effects of Epimedium extractive.Methods By using the uterus growth test in mice and test of MCF-7 proliferation and adding estrogen receptor antagonist Icariin,we evaluated the estrogenic effects of Epimedium and Icariin and the possible mechanism.Results Epimedium and Icariin increased significantly the uterus coefficient in mice from 0.097?0.008 to 0.156?0.018 and 0.152?0.016,respectively;the weight increased significantly from(18.9?1.3)g to(19.8?1.3)g and(20.03?1.3)g(P