The Effect And Role Of Estrogen On The Expression Of Caveolin-1 At Different Stages Of Osteoblasts

Objective:To investigate the effect of estrogen on the expression of caveolin-1 protein in osteoblastic MC3T3-E1. To study the role of caveolin-1 playing on the regulation of estrogen on differentiation of MC3T3-E1.Methods:Adding estrogen to MC3T3-E1 at proliferative phase (2nd d), differentiational phase(6th d), and mineralizational phase(12th d) for 48h, to observe the expression changes of caveolin-1 protein via Western Blotting.Estrogen and caveolin-1 eukaryotic expression plasmid Pcl-neo-cav-1 were applied in MC3T3-E1 cell at the differentiation phase, and the mRNA expression of osteoblastic specific transcriptional factor cbfa-1(RT-PCR), ALP activity in cell lysis (PNPP) and osteocalcin(OCN)concentration (ELISA) in medium were investigated. Nitric oxide (NO) were measured to study the mechanism of caveolin-1.Results:1. In MC3T3 cell, estrogen apparently down-regulated protein expression of caveolin-1 at differentiational phase, and has no obvious effect on cell at proliferative or mineralizational phase.2. Estrogen can promote ALP activity, increase the concentration of osteoclacin and increase mRNA expression of caveolin-1, which were abolished by caveolin-1 expression plasmid Pcl-neo-cav-1 (P<0.01).The concentration of NO in medium were found no changed.Conclusion:Caveolin-1 may negative regulate the promoting differentiation effect of estrogen on osteoblastic MC3T3-E1at differentiational phrase, which is no related to NO pathway.