Effect Of Estrogen Receptor Beta On Balance Between Osteogenic And Adipogenic Differentiation In Bone Marrow Matrix Stem Cells

Tooth movement in bone is progress of bone formation and absorb during orthodontic.Bone physiological rebuild is the foundation of tooth movement, consequently, growth and metabolism of bone effect orthodontic therapeutic directly and mediately. Estrogen which is one of important conditions of regulation of bone rebuilding performs through estrogen receptors. Weather estrogen receptor beta participate to mediate bone rebuilding of bone marrow mesenchymal stem cell is pending further demonstration.RNAi can down regulation definite expression and reproduction of gene specially, which has been used for functional gene research and get delectable advancements. We studied the effects of estrogen receptor beta(ERβ) specific small interfering RNA (siRNA) on osteoblasts and adipocytes induction in rat bone mesenchymal stem cells(rBMSCs). The research consists the following objectives:1 .Three vectors expressing specific hairpin siRNA were constructed and transfected into rBMSCs.2 Balance between osteoblast and adipogenic differentiation in diffetent weeks SD rBMSCs.To study the regulation of adipogenic differentiation in different weeks Sprague Dawleg rats marrow mesenchymal stem cells. Different weeks (young:2 weeks, adult: 3 months, older :18 months) Sprague Dawleg rats marrow mesenchymal stem cells were separated and cultivated and expanded in vitro. To induce the rBMSCs to differentiate into osteoblast and adipogenic in vitro,Von Kossa staining for mineralized nodule formation and Oil Red-O staining for adipogenic.The cells cultured were identified as bone marrow mesenchymal stem cells .The percents of area of mineralize in the group of younger rats were highest. The percents of positive cells of Oil Red-O staining in the group of older rats were highest.The ability of osteoblast differentiation were weak while the ability of adipogenic differentiation were strong with the weeks adding.3 To study the regulation of ERβSprague Dawleg rats marrow mesenchymal stem cells during differentiating into adipogenic in vitro.Sprague Dawleg rats marrow mesenchymal stem cells were separated and cultivated. To induce the rBMSCs to adipogenic in vitro,ERβprotein was examined by Western blot in different stages.The cells cultured were identified as marrow mesenchymal stem cells.The protein stripes in Western blot of ERβwere clearer with time adding during differentiating adipogenic .ERβprotein in Sprague Dawleg rats marrow mesenchymal stem cells were high with the time adding during differentiating adipogenic .4 After transfected by siRNA ERβin rat BMSC,the ERβexpression was detected by semi-quantitative Rt-PCR. After osteogenic differentiation of rBMSCs, alkaline phosphatase(ALP) was detected by kit and mineralized matrix was stained by Alizarin Red S staining. And after adipogenic differentiation of rBMSCs, lipoprotein lipase (LPL) was detected by semi-quantitative RT-PCR and lipid vesicles were stained by Oil Red-O staining.The results showed that the ERβmRNA was significantly inhibited by siRNA in rBMSCs. Knockdown of ERβwith siRNA increased the expression of alkaline phosphatase and induced matrix calcification by the osteogenic induced BMSC. In contrast, expression of LPL mRNA and lipid vesicles was decreased visibly after adipogenic differentiation in siERβrBMSCs.In conclusion, these findings indicate that ERβmaybe play important roles in estrogen-induced modulates osteogenic and adipogenic differentiation function of rBMSCs. Prefession of ERβcan regulate the balance of osteogenic and adipogenic differentiation in rBMSC.