Epigallocatechin-3-gallate Protects against Hydrogen Peroxide-Induced Inhibition of Osteogenic Differentiation of Human Bone Marrow-Derived Mesenchymal Stem Cells.

Dawei Wang,Daqing Sun,Shihong Xu,Yonghui Wang,Bomin Wang,Lianxin Li,Fu Wang,Ke Han

doi:10.1155/2016/7532798

Abstract

Oxidative stress induces bone loss and osteoporosis, and epigallocatechin-3-gallate (EGCG) may be used to combat these diseases due to its antioxidative property. Herein, oxidative stress in human bone marrow-derived mesenchymal stem cells (BM-MSCs) was induced by H2O2, resulting in an adverse effect on their osteogenic differentiation. However, this H2O2-induced adverse effect was nullified when the cells were treated with EGCG. In addition, treatment of BM-MSCs with EGCG alone also resulted in the enhancement of osteogenic differentiation of BM-MSCs. After EGCG treatment, expressions of β-catenin and cyclin D1 were upregulated, suggesting that the Wnt pathway was involved in the effects of EGCG on the osteogenic differentiation of BM-MSCs. This was also confirmed by the fact that the Wnt pathway inhibitor, Dickkopf-1 (DKK-1), can nullify the EGCG-induced enhancement effect on BM-MSC's osteogenic differentiation. Hence, our results suggested that EGCG can reduce the effects of oxidative stress on Wnt pathway in osteogenic cells, which supported a potentially promising therapy of bone disorders induced by oxidative stress. Considering its positive effects on BM-MSCs, EGCG may also be beneficial for stem cell-based bone repair.

Highlights

Several types of polyphenols, including green tea polyphenols, grape polyphenols, and blueberry polyphenols, have been reported to be capable of promoting bone formation, preventing bone loss, and influencing osteogenic differentiation [1,2,3,4]
Cell Counting Assay Kit 8 (CCK-8) assay results demonstrated that the viability of Bone marrow-derived mesenchymal stem cells (BMMSCs) was reduced with increasing concentrations of H2O2 in the cell culture medium
bone marrow-derived mesenchymal stem cells (BM-MSCs) were treated with the combination of 0.2 mM H2O2 and 5 μM EGCG, and the results showed that EGCG almost completely nullified the H2O2-induced reduction on cell viability over 7 days (Figure 1(d))

Summary

Introduction

Several types of polyphenols, including green tea polyphenols, grape polyphenols, and blueberry polyphenols, have been reported to be capable of promoting bone formation, preventing bone loss, and influencing osteogenic differentiation [1,2,3,4]. Epigallocatechin-3-gallate (EGCG) is the most abundant catechin polyphenol extracted from green tea, constituting 9–13% of the total dry weight [5]. Due to its antioxidant and free radical scavenger properties, EGCG has been proposed to have protective effects for organ impairments induced by ischemia, toxins, stress, and hypertension [6, 7]. Oxidative stress may be associated with the pathophysiology of many organs. Generation of reactive oxygen species (ROS) can influence the homeostasis, since

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