(−)-Epigallocatechin-3-Gallate Decreases Osteoclastogenesis via Modulation of RANKL and Osteoprotegrin
Shih-Tse Chen,
Lin Kang,
Chau-Zen Wang,
Peng-Ju Huang,
Hsuan-Ti Huang,
Sung-Yen Lin,
Shih-Hsiang Chou,
Cheng-Chang Lu,
Po-Chih Shen,
Yi-Shan Lin,
Chung-Hwan Chen
Affiliations
Shih-Tse Chen
Department of Psychiatry, National Taiwan University Hospital Hsin-Chu Branch, Hsin Chu 30059, Taiwan
Lin Kang
Department of Obstetrics and Gynecology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 70101, Taiwan
Chau-Zen Wang
Orthopaedic Research Center, Kaohsiung Medical University, Kaohsiung 80701, Taiwan
Peng-Ju Huang
Department of Orthopedics, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 80701, Taiwan
Hsuan-Ti Huang
Department of Orthopedics, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 80701, Taiwan
Sung-Yen Lin
Orthopaedic Research Center, Kaohsiung Medical University, Kaohsiung 80701, Taiwan
Shih-Hsiang Chou
Department of Orthopedics, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 80701, Taiwan
Cheng-Chang Lu
Department of Orthopedics, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 80701, Taiwan
Po-Chih Shen
Department of Orthopedics, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 80701, Taiwan
Yi-Shan Lin
Orthopaedic Research Center, Kaohsiung Medical University, Kaohsiung 80701, Taiwan
Chung-Hwan Chen
Orthopaedic Research Center, Kaohsiung Medical University, Kaohsiung 80701, Taiwan
Osteoporosis is the second most common epidemiologic disease in the aging population worldwide. Previous studies have found that frequent tea drinkers have higher bone mineral density and less hip fracture. We previously found that (−)-epigallocatechin gallate (EGCG) (20–100 µmol/L) significantly suppressed receptor activator of nuclear factor-kB ligand (RANKL)-induced osteoclastogenesis and pit formation via inhibiting NF-κB transcriptional activity and nuclear transport of NF-κB in RAW 264.7 cells and murine primary bone marrow macrophage cells. The most important regulation in osteoclastogenesis is the receptor activator of nuclear factor-kB/RANKL/osteoprotegrin (RANK/RANKL/OPG) pathway. In this study, we used the coculture of RAW 264.7 cells and the feeder cells, ST2, to evaluate how EGCG regulated the RANK/RANKL/OPG pathway in RAW 264.7 cells and ST2 cells. We found EGCG decreased the RANKL/OPG ratio in both mRNA expression and secretory protein levels and eventually decreased osteoclastogenesis by TRAP (+) stain osteoclasts and TRAP activity at low concentrations—1 and 10 µmol/L—via the RANK/RANKL/OPG pathway. The effective concentration can be easily achieved in daily tea consumption. Taken together, our results implicate that EGCG could be an important nutrient in modulating bone resorption.
