Epigallocatechin-3-gallate Promotes Osteoblastic Activity in Human Osteoblast-like Cells

Purpose: To investigate the effect of epigallocatechin-3-gallate (EGCG) on bone metabolism and osteoblastic activity. Methods: MG-63 human osteoblast-like cells were treated with varied concentrations of EGCG. Alkaline phosphatase (ALP) activity and matrix mineralization assays were carried out on the treated and untreated MG-63 human osteoblast-like cells. Beta-catenin mRNA level was determined by quantitative real-time polymerase chain reaction (q-PCR). Results: The results showed that EGCG treatment significantly increased ALP and mineralization activities at concentrations of 15 and 30 mu M, in a dose-dependent manner. Furthermore, EGCG treatment significantly increased beta-catenin mRNA expression by 70.7 +/- 11.0 and 126.7 +/- 35.1 %, respectively, at EGCG concentration of 15 and 30 mu M. In addition, the stimulating effect of EGCG treatment on ALP activity was abolished by co-treatment with ICI 182,780, an antagonist of estrogen receptor (ER). Again, the increase in beta-catenin MRNA, when treated with EGCG, was inhibited by co-treatment with ICI 182,780. Conclusion: EGCG promotes osteoblastic activity in human osteoblast-like cells, by Wnt signaling through estrogen receptor (ER) pathway.