Protective effects of pueraria isoflavones on myocardial injury in ovariectomized rats via LKB1/AMPK/PGC-1α signaling pathway
AIM To study the protective effects and mechanism of pueraria isoflavones on myocardial injury in ovariectomized rats.METHODS Thirty-six rats were randomly divided into the sham operation group,the model group,the estradiol valerate group(0.1 mg/kg)and the low,medium and high dose pueraria isoflavones groups(55,110,220 mg/kg).In contrast to the rats of the sham operation group having their small pieces of adipose tissue removal around the ovaries,rats of the other groups had their bilateral ovaries excised,followed by the 16-week corresponding oral drug administration 2 weeks later at a once daily frequency for,6 days a week.At the end of the 16th week,the rats had their hemodynamics[systolic pressure(SBP),diastolic pressure(DBP),mean pressure(MBP),left ventricular systolic pressure(LVSP),left ventricular diastolic pressure(LVMP),and the maximum rate of increase and decrease of left ventricular pressure during isovolumic contraction(±dp/dtmax)]detected by PowerLab;their cardiac pathological changes observed by HE staining;their levels of creatine kinase(CK),lactate dehydrogenase(LDH),total cholesterol(TC),triglyceride(TG),high density lipoprotein cholesterol(HDL-C),low density lipoprotein cholesterol(LDL-C)and glucose(Glu)in plasma detected by biochemical analyzer;their myocardial level of adenosine triphosphate(ATP)detected by colorimetry;their mRNA expressions of glucose transporter 4(GLUT4),lactate dehydrogenase A(LDHA),carnitine palmitoyl transferase-1(CPT-1α),acyl coenzyme A carboxylase(ACC),liver kinase B1(LKB1),adenylate-activated protein kinase(AMPK)and peroxisome proliferator-activated receptor γ coactivator factor 1α(PGC-1α)detected by RT-qPCR;and their myocardial expressions of energy metabolism related proteins LKB1,p-AMPK/AMPK and PGC-1α detected by Western blot.RESULTS Compared with the model group,the pueraria isoflavones groups displayed decreased levels of SBP,DBP,MBP,LVSP,LVMP(P＜0.05,P＜0.01);increased-dp/dtmax(P＜0.05,P＜0.01);improved myocardial fibrinolysis,gap widening and inflammatory infiltration caused by ovariectomy;decreased activities of LDH and CK(P＜0.05);increased myocardial ATP level(P＜0.05,P＜0.01);decreased levels of TC,TG,LDL-C and Glu(P＜0.05,P＜0.01);increased HDL-C level(P＜0.05,P＜0.01);increased myocardial mRNA expressions of GLUT4,LDHA,CPT-1α,ACC,LKB1,AMPK and PGC-1α(P＜0.05,P＜0.01);and increased protein expressions of myocardial LKB1,p-AMPK/AMPK and PGC-1α(P＜0.05,P＜0.01).CONCLUSION Pueraria isoflavones are protective to myocardial injury in ovariectomized rats,and the mechanism may lie in the improvement of energy metabolism-related myocardial proteins via LKB1/AMPK/PGC-1α signaling pathway.
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