Baicalein, an active component of Scutellaria baicalensis Georgi, prevents lysophosphatidylcholine-induced cardiac injury by reducing reactive oxygen species production, calcium overload and apoptosis via MAPK pathways

Huai-Min Chen,Shu-Fen Liou,Jwu-Lai Yeh,Chaw-Chi Chiu,Jong-Hau Hsu,Tsan-Ju Chen,Li-Ying Chen

doi:10.1186/1472-6882-14-233

Abstract

BackgroundLysophosphatidylcholine (lysoPC), a metabolite from membrane phospholipids, accumulates in the ischemic myocardium and plays an important role in the development of myocardial dysfunction ventricular arrhythmia. In this study, we investigated if baicalein, a major component of Huang Qui, can protect against lysoPC-induced cytotoxicity in rat H9c2 embryonic cardiomyocytes.MethodsCell viability was detected by the MTT assay; ROS levels were assessed using DCFH-DA; and intracellular free calcium concentrations were assayed by spectrofluorophotometer. Cell apoptosis and necrosis were evaluated by the flow cytometry assay and Hoechst staining. Mitogen-Activated Protein Kinases (MAPKs), which included the ERK, JNK, and p38, and the apoptotic mechanisms including Bcl-2/Bax, caspase-3, caspase-9 and cytochrome c pathways were examined by Western blot analysis. The activation of MAPKs was examined by enzyme-linked immunosorbent assay.ResultsWe found that lysoPC induced death and apoptosis of H9c2 cells in a dose-dependent manner. Baicalein could prevent lysoPC-induced cell death, production of reactive oxygen species (ROS), and increase of intracellular calcium concentration in H9c2 cardiomyoctes. In addition, baicalein also inhibited lysoPC-induced apoptosis, with associated decreased pro-apoptotic Bax protein, increased anti-apoptotic Bcl-2 protein, resulting in an increase in the Bcl-2/Bax ratio. Finally, baicalein attenuated lysoPC-induced the expression of cytochrome c, casapase-3, casapase-9, and the phosphorylations of ERK1/2, JNK, and p38. LysoPC-induced ERK1/2, JNK, and p38 activations were inhibited by baicalein.ConclusionsBaicalein protects cardiomyocytes from lysoPC-induced apoptosis by reducing ROS production, inhibition of calcium overload, and deactivations of MAPK signaling pathways.

Highlights

Lysophosphatidylcholine, a metabolite from membrane phospholipids, accumulates in the ischemic myocardium and plays an important role in the development of myocardial dysfunction ventricular arrhythmia
Antibodies to Bcl-2, Bax, ERK1/2, JNK and phosphorylated JNK were obtained from Upstate Biotechnology (Lake Placid, NY, USA) while antibodies of p38, phosphorylated p38 and cytochrome c were obtained from Santa Cruz Biotech (Santa Cruz, CA, USA)
Baicalein inhibited cell death induced by lysoPC To determine the dose–response effects of lysoPC on death of rat H9c2 cells, a series of experiments was performed using the MTT assay in different concentrations of lysoPC

Summary

Introduction

Lysophosphatidylcholine (lysoPC), a metabolite from membrane phospholipids, accumulates in the ischemic myocardium and plays an important role in the development of myocardial dysfunction ventricular arrhythmia. We investigated if baicalein, a major component of Huang Qui, can protect against lysoPC-induced cytotoxicity in rat H9c2 embryonic cardiomyocytes. LysoPC can induce the increase of the intracellular Ca2+ concentration ([Ca2+]i) and plays an important role in triggering onset of arrhythmias in cardiac ischemia [2]. Oxidative stress in cardiomyocytes plays an important role in the pathogenesis of both heart failure and ischemic reperfusion injury. The compositions of baicalein, wagonin, skullcap-flavone I & II in Huang Qui all have anti-oxidative effects, so Huang Qui has been implicated in the prevention of the ischemia-reperfusion injuries and in the reduction of the ROS productions [7,8]. In previous studies baicalein has been found to effectively lower ROS-induced cells death in chicken fetal cardiomyocytes in the setting of hypoxic injury [7,8,9]

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