The anti-apoptotic and cardioprotective effects of salvianolic acid a on rat cardiomyocytes following ischemia/reperfusion by DUSP-mediated regulation of the ERK1/2/JNK pathway.

Tongda Xu,Yang Liu,Dongye Li,Qiuping Chen,Xiaohu Chen,Shasha Zhu,Defeng Pan,Xin Wu,Anindita Das

doi:10.1371/journal.pone.0102292

Abstract

The purpose of this study was to observe the effects of salvianolic acid A (SAA) pretreatment on the myocardium during ischemia/reperfusion (I/R) and to illuminate the interrelationships among dual specificity protein phosphatase (DUSP) 2/4/16, ERK1/2 and JNK pathways during myocardial I/R, with the ultimate goal of elucidating how SAA exerts cardioprotection against I/R injury (IRI). Wistar rats were divided into the following six groups: control group (CON), I/R group, SAA+I/R group, ERK1/2 inhibitor PD098059+I/R group (PD+I/R), PD+SAA+I/R group, and JNK inhibitor SP600125+I/R group (SP+I/R). The cardioprotective effects of SAA on the myocardium during I/R were investigated with a Langendorff device. Heart rate (HR), left ventricular systolic pressure (LVSP), left ventricular end-diastolic pressure (LVEDP), maximum rate of ventricular pressure rise and fall (±dp/dtmax), myocardial infarction areas (MIA), lactate dehydrogenase (LDH), and cardiomyocytes apoptosis were monitored. To determine the crosstalk betwee JNK and ERK1/2 via DUSP2/4/16 with SAA pretreatment, siRNA-DUSP2/4/16 were performed. The expression levels of Bcl-2, Bax, caspase 3, p-JNK, p-ERK1/2 and DUSP2/4/16 in cardiomyocytes were assayed by Western blot. Our results showed that LDH, MIA and cell apoptosis were decreased, and various parameters of heart function were improved by SAA pretreatment and SP application. In the I/R group, the expression levels of p-ERK1/2 and DUSP4/16 were not significantly different compared with the CON group, however, the protein expression levels of p-ERK1/2, Bcl-2 and DUSP4/16 were higher, while p-JNK, Bax, caspase 3 and DUSP2 levels were reduced among the SAA+I/R, PD+SAA+I/R and SP+I/R groups. The above indices were not significantly different between the SAA+I/R and SP+I/R groups. Compared with the SAA+I/R group, p-ERK1/2 was increased and p-JNK was decreased in the SAA+si-DUSP2+I/R, however, p-ERK was downregulated and p-JNK was upregulated in SAA+si-DUSP4+I/R group. SAA exerts an anti-apoptotic role against myocardial IRI by inhibiting DUSP2-mediated JNK dephosphorylation and activating DUSP4/16-mediated ERK1/2 phosphorylation.

Highlights

Ischemic heart disease remains one of the leading causes of death all over the world, and its global prevalence is continuously increasing
The damaged structure and heart function can be restored to its basal condition through ischemia/reperfusion (I/R), in some cases reperfusion can augment ischemic injury of the heart, a situation termed as myocardial ischemia-reperfusion injury (IRI) [1]
Compared with the I/R group, improvements were seen in the Heart rate (HR), left ventricular systolic pressure (LVSP), 6dp/dtmax values of the salvianolic acid A (SAA)+I/R, PD+SAA+I/R and SP600125+I/R group (SP+I/R) groups, and left ventricular end-diastolic pressure (LVEDP) could be lowered (P,0.05), HR, LVSP, LVEDP and 6dp/dtmax values were not significantly different in the PD098059+I/R group (PD+I/R) group

Summary

Introduction

Ischemic heart disease remains one of the leading causes of death all over the world, and its global prevalence is continuously increasing. Myocardial ischemia results in a lack of myocardial oxygen supply, which can damage myocardial structure and heart function. It is necessary for damaged myocardium to restore the supply of oxygen and nutrients and to improve its functional recovery through myocardial reperfusion. The damaged structure and heart function can be restored to its basal condition through ischemia/reperfusion (I/R), in some cases reperfusion can augment ischemic injury of the heart, a situation termed as myocardial ischemia-reperfusion injury (IRI) [1]. A large body of literature indicates that cell apoptosis can be induced during I/R, and this is one of the main components involved in myocardial IRI. Some experiments and clinical studies have suggested that cell apoptosis may be an important link during the pathogenesis of myocardial IRI [2,3]

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