Baicalin alleviates H2O2-induced injury of H9c2 cardiomyocytes through suppression of the Wnt/beta-catenin signaling pathway

摘要

Baicalin is one of the active ingredients extracted from the dry root of Scutellaria baicalensis Georgi, which has been reported to be effective in preventing myocardial ischemia reperfusion injury. However, the mechanisms underlying its cardioprotective activities remain to be elucidated. In the present study, H2O2-treated cardiomyocyte H9c2 cell line served as an in vitro model of oxidation-damaged cardiomyocytes to evaluate the effects of baicalin on the cardiac injury, and to investigate the underlying molecular mechanism. The results of the TOPFlash/Renilla reporter gene assay indicated that baicalin significantly suppressed the activation of proto-oncogene Wnt-1 (Wnt)/beta-catenin in 293 cells, in a dose dependent manner. In addition, baicalin significantly inhibited H2O2-induced loss of H9c2 cell viability in MTT assay. Furthermore, western blotting analysis demonstrated that baicalin markedly attenuated H2O2-induced cell apoptosis, as demonstrated by the down-regulation of cleaved caspase-3 and the increase in the apoptosis regulator Bcl-2 (Bcl-2)/apoptosis regulator BAX (Bax) ratio following baicalin treatment in H2O2-treated H9c2 cells. Furthermore, baicalin markedly decreased the expression of beta-catenin and downstream Axin-2 and myc proto-oncogene protein in H2O2-treated H9c2 cells. Knockdown of beta-catenin expression inhibited H2O2-induced cell apoptosis. Finally, LiCl (a beta-catenin stabilizer) induced apoptosis of H9c2 cells by upregulating the expression of beta-catenin, which was significantly neutralized by the treatment with baicalin. Taken together, it is hypothesized that baicalin exerts cardioprotective effects via suppression of the Wnt/beta-catenin signaling pathway.