IGF-1 Effect On The Proliferation And Type â…  Collagen Synthesis And OPG/RANKL MRNA Expession In MC3T3-E1 Osteoblasts Of Mice

ObjectiveObservation of insulin-like growth factor 1(IGF-1) on cultured mouse pre-osteoblast-like MC3T3-E1 cell proliferation and typeⅠcollagen synthesis and OPG mRNA,RANKL mRNA levels to explore the possible mechanism of the IGF-1 on bone metabolism.Methods(1) Serial subcultivation of Murine preosteoblastic line MC3T3-E1.(2) MC3T3-E1 were cultured with different dose of IGF-1.Cell proliferation was assessed by OD that analysed though MTT colorimetric assay(IGF-10,1.0,10,50,100 ng/ml).(3) MC3T3-E1 were cultured with different dose of IGF-1.Detection of typeⅠcollagen protein synthesis by immunohistochemical and RT-PCR method.(4) MC3T3-E1 were cultured with different dose of IGF-1(0,50,100 ng/ml).The expressions of OPG,RANKLmRNA were obtained with RT-PCR.(5) Statistical analysis:Date are presented as(?)±s.All statistical analysis was performed with Windows SPSS 11.5.The differences between the groups were determined by One-way ANOVE.Differences were considered significant at a value of P＜0.05.Results(1).Proliferation of MC3T3-E1 was promoted by IGF-1 in serum hungry after 24 hour. Compared with the control group,proliferation of MC3T3-E1 was promoted in the trial groups by MTT and the difference is significance(P＜0.05),(2).By IGF-1 stimulation of osteoblast-I collagen protein expression was significantly higher than the control group(p＜0.001);RT-PCR showed that after IGF-1 intervention 24h,collagen typeⅠmRNA expression was increased significantly than the control group(p＜0.05).(3).RT-PCR examination revealed OPGmRNA expression in each group after IGF-1 subculture 24 hour.IGF-1 promote OPG mRNA expression and inhibit the RANKL mRNA expression,in dose-dependent manner.(p＜0.01).Conclusions(1) IGF-1 on MC3T3-E1 cell proliferation has a clear role in the 1～100 ng /ml dose-dependent manner.(2) IGF-1 can promote osteoblast-I collagen synthesis and its mRNA expression.(3) IGF-1 promotes OPG mRNA expression and inhibits RANKL mRNA expression.