| ObjectiveObservation of insulin-like growth factor 1 (IGF-1) on cultured mouse pre-osteoblast-like MC3T3-E1 cell proliferation and type I collagen 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-1 0,1.0,10,50,100 ng/ml).(3) MC3T3-E1 were cultured with different dose of IGF-1. Detection of type I collagen 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 x±s .All statistical analysis was performed with Windows SPSS11.5. 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 type I mRNA 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. |
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