Protective effects of Phyllanthus emblica against myocardial ischemia-reperfusion injury: the role of PI3-kinase/glycogen synthase kinase 3 beta/beta-catenin pathway

摘要

Clinical studies of Phyllanthus emblica (P. emblica) have shown that it increases production of nitric oxide, glutathione, and high-density lipoprotein (HDL); decreases low-density lipoprotein (LDL), total cholesterol, triglycerides, and high-sensitivity C-reactive protein (hsCRP); and significantly inhibits platelet aggregation. The following study was designed to examine the effect of P. emblica treatment on myocardial ischemia-reperfusion (I/R) injury and identify the molecular targets and its underlying mechanism(s). Experimental animals were divided into four groups: control sham (CS), P. emblica sham (PS), control I/R (CIR), and P. emblica I/R (PIR). Rats in the P. emblica groups were gavaged with aqueous P. emblica solution (100 mg/kg body weight) for 30 days. After 30 days of gavaging, the I/R group underwent I/R surgery (45-min ischemia) followed by 4 or 30 days of reperfusion. Rats in the sham group underwent surgery without ligation. Left ventricular tissue samples, 4 and 30 days after I/R, were used for Western blot analysis and immunohistochemistry, respectively. Western blot analysis showed upregulation of phosphorylated Akt and GSK3-beta and increased nuclear translocation of beta-catenin in the PIR group versus CIR. PIR rats also indicated reduced 3-nitrotyrosine and Caspase-3 expression. Increased phosphorylation of endothelial nitric oxide synthase (p-eNOS) and upregulation of anti-apoptotic protein Bcl-2 were found in the PIR group. Echocardiography showed increased ejection fraction and fractional shortening and decreased left ventricular internal diameter in experimental subjects compared to controls. There was decreased fibrosis in P. emblica-treated rats compared to controls. The results of this study indicate that P. emblica is capable of upregulating the PI3K/Akt/GSK3 beta/beta-catenin cardioprotective pathway, thereby preserving cardiac tissue during ischemia-reperfusion injury.