%0 Journal Article
%T Tanshinol Attenuates the Deleterious Effects of Oxidative Stress on Osteoblastic Differentiation via Wnt/FoxO3a Signaling
%A Yajun Yang
%A Yanjie Su
%A Dongtao Wang
%A Yahui Chen
%A Tie Wu
%A Gang Li
%A Xuegang Sun
%A Liao Cui
%J Oxidative Medicine and Cellular Longevity
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/351895
%X There is now increasing evidence which suggests a pivotal role for oxidative stress in the development and progression of osteoporosis. We confirm herein the protective effects of natural antioxidant Tanshinol against oxidative stress in osteoblastic differentiation and the underlying mechanism. Our results show that hydrogen peroxide (H2O2) leads to accumulation of reactive oxygen species (ROS), decrease in cell viability, cell cycle arrest and apoptosis in a caspase-3-dependent manner, and inhibition of osteoblastic differentiation. Tanshinol reverses these deleterious consequence triggered by oxidative stress. Moreover, under the condition of oxidative stress, Tanshinol suppresses the activation of FoxO3a transcription factor and expressions of its target genes Gadd45a and catalase (CAT) and simultaneously counteracts the inhibition of Wnt signalling and expressions of target genes Axin2, alkaline phosphatase (ALP), and Osteoprotegerin (OPG). The findings are further consolidated using FoxO3a siRNA interference and overexpression of Tcf4. The results illustrate that Tanshinol attenuates oxidative stress via down-regulation of FoxO3a signaling, and rescues the decrease of osteoblastic differentiation through upregulation of Wnt signal under oxidative stress. The present findings suggest that the beneficial effects of Tanshinol may be adopted as a novel therapeutic approach in recently recognized conditions of niche targeting osteoporosis. 1. Introduction Extensive evidence indicates that ˇ°oxidative stressˇ± theory has currently been proposed as a new intensive mechanism that the development and progression of osteoporosis are in connection with an increase of oxidative stress, which leads to degenerative disease of bone tissue [1, 2]. Understanding of oxidative stress is currently a substantial topic of investigation with the aim of developing new ways to diminish negative effects of oxidative damage on bone metabolism [3]. Starting in their mid-40s, both genders experience a progressive decrease in bone mass and bone quality [2], associated with aging [4], some illnesses, or use of medications, such as diabetes or excessive exposure to glucocorticoids [5¨C7]. Notwithstanding, as for the evidence for physiological levels of reactive oxygen species (ROS) helpful in sustaining cellular function [8], it is generally believed that excessive accumulation of ROS causes oxidative stress and destroys proteins, lipids, and DNA, consequentially leading to cell death [9]. Based on current understanding of the cellular events of bone formation phase in the process
%U http://www.hindawi.com/journals/omcl/2013/351895/