- 期刊
Green Tea Catechins Enhance the Expression of Osteoprotegerin (OPG) in Pluripotent Sten Cells
綠茶兒茶素增加多功能幹細胞osteoprotegerin（OPG）之表現
並列摘要
The major catechins in green tea are (-)-epicatechin (EC), (-)-epicatechin gallate (EGC), (-)-epigallocatechin (EGC), and (-)-epigalloncatechin-3-gallate (EGCG). Recent studies have verified the beneficial effect of catechins in decreasing serum lipid, reducing blood pressure, and modulating immune responses and for use as antitumorigenic and antibacterial agents. Prior epidemiological studies found that the bone mineral density (BMD) of postmenopausal women with tea drinking habit was higher than that without tea consumption. This study aimed to investiage the effects of green tea catechins on the osteogenic effect in pluripotent stem cells. Osteoprotegerin (OPG), which is mainly produced by the cells of the osteoblastic lineage, plays a key role in regulating osteoclastogenesis via the OPG/RANK-L/RANK system. OPG acts as the decoy receptor binding with RANK, which is essential for osteoclastogenesis. OPG can, in turn, inhibit osteoclast differentiation and activity. Accordingly, it can thwart the differentiation, survival, and fusion of osteoclastic precursor cells, block the activity of mature osteoclasts, and induce osteoclast apoptosis. The effects of all four major ingredients of catechins on OPG expressions were analyzed. We identified that ECGC increased the mRNA expression of OPG. This result suggests that EGCG may enhance osteogenic and suppress osteoclastic functions through the effects of OPG. Our result also showed that the most effective concentration of EGCG is at the concentration range of 10-6 M to -10-5 M. Our results, suggest that green tea might be a beverage for preventing osteoporosis through enhancing OPG expression.