ABSTRACT
OBJECTIVE: To investigate the effect of n-hexane on the level of sex hormones and expression of estrogen receptor(ER) in rats and the protective effect of Lyciumbarbarum polysaccharide(LBP) on n-hexane-induced reproductive toxicity. METHODS: Based on factorial design model of 4×2, specific pathogen free adult female SD rats were divided into control group and low-, medium-and high-n-hexane exposure groups, and each group was divided into non-LBP intervention and LBP intervention sub-group. There were 8 subgroups with 6 rats in each group. On the first day, the rats in the 4 groups were given intraperitoneal injection of n-hexane at 0, 675, 1 350 and 2 700 mg/kg body weight, respectively. On day 2-4, the rats in the non-LBP intervention subgroup were given intragastric administration of 0.9% sodium chloride solution, and the rats in the LBP intervention subgroup were given intragastric administration of LBP at 50 mg/kg body weight once a day. On the fifth day, all animals were sacrificed, and the levels of follicle stimulating hormone(FSH), luteinizing hormone(LH), estradiol, progesterone were detected by enzyme linked immunosorbent assay. The mRNA expression of Erα, Erβ and G protein coupled estrogen receptor 1(Gper1) was detected by real time fluorescence polymerase chain reaction, and the expression of ERα, ERβ and GPER1 protein was detected by Western blotting. RESULTS: i) In the absence of LBP intervention(i.e. simple n-hexane exposure), there was no significant difference in the level of serum FSH, LH, estradiol and progesterone in the 4 groups(P>0.05). The relative expression of Erβ mRNA in ovary of low dose group decreased, while the relative expression of proteins of ERα and GPER1 increased(P<0.05) when compared with the control group. The relative expression of Erα mRNA and GPER1 protein in the ovary of medium-and high-dose groups increased(P<0.05), while the relative expression of Erβ, Gper1 mRNA and ERβ protein decreased(P<0.05). The relative expression of ERα protein in ovary of high-dose group increased(P<0.05). ii) At the same dose of n-hexane exposure, the relative expression of Erα mRNA in ovary of rats in low dose group increased(P<0.05), while the relative expression of ERβ and GPER1 protein decreased in LBP intervention group compared with the no LBP intervention group(P<0.05). The relative expression of ERα and GPER1 protein in ovary of medium dose group increased(P<0.05), while the relative expression of Gper1 mRNA and GPER1 protein in ovary of high dose group decreased in LBP intervention group compared with the no LBP intervention group(P<0.05). CONCLUSION: n-Hexane can up-regulate the expression of ERα and GPER1 in rat ovary, but has no significant effect on female endocrine system. LBP may play a protective role in female reproductive system by up-regulating the expression of ERα and GPER1.
ABSTRACT
OBJECTIVE: To study the effects of cadmium on the expression of estrogen receptor( ER) and miRAN-155,miRAN-200 c in human breast cancer MCF-7 cells. METHODS: MCF-7cells in logarithmic growth phase were randomly divided into fulvestrant( ICI182780,ICI) group and non-ICI group. The non-ICI group was treated with cadmium chloride(Cd Cl2) at the final concentrations of 0. 0,2. 5,5. 0 and 10. 0 μmol/L for 24 hours. The ICI group was pretreated at a concentration of 1. 0 μmol/L for 12 hours,and then treated with Cd Cl2 at the final concentrations 0. 0,2. 5,5. 0 and 10. 0μmol/L for 24 hours. The cell proliferation activity was measured by methyl thiazolyl tetrazolium assay. Flow cytometry was used to measured cell apoptosis. Western blot was applied to measure the relative expression of ERα and ERβ protein,and the relative expression of miRNA-155 and miRNA-200 c were detected by real-time fluorescence quantitative polymerase chain reaction. RESULTS: The proliferation rates of MCF-7 cells in 2. 5,5. 0 and 10. 0 μmol/L Cd Cl2 groups were significantly decreased than the 0. 0 μmol/L Cd Cl2 group( P < 0. 05). The proliferation rate in ICI group was lower than that of the non-ICI group( P < 0. 05). When Cd Cl2 concentration was 2. 5,5. 0 and 10. 0 μmol/L,the apoptosis rate of MCF-7 cells in non-ICI group increased compared with those cells without exposure to Cd Cl2( P < 0. 05). The relative expression of ERα,ERβ,miRNA-155 and miRNA-200 c increased( P < 0. 05). The proliferation of MCF-7 cells in ICI group decreased( P < 0. 05),and the relative apoptosis rate increased( P < 0. 05); and the relative expression of ERαand ERβ increased( P < 0. 05),the relative expression of miRNA-155 and miRNA-200 c decreased( P < 0. 05). When treated without Cd Cl2,the apoptosis rate of the ICI group increased compared with non-ICI group(P < 0. 05),the relative expression of ERα and ERβ decreased( P < 0. 05),and the relative expression of miRNA-155 and miRNA-200 c were increased( P < 0. 05). When Cd Cl2 concentration was 2. 5,5. 0 and 10. 0 μmol/L,the apoptosis rate and the relative expression of ERα,ERβ,miRNA-155 and miRNA-200 c decreased compared with the non-ICI group treated with same dose Cd Cl2(P < 0. 05). CONCLUSION: Cadmium can induce cell apoptosis and increase expression of miRNAs through the ER signaling pathway.