Effect of rheum offcinale baill on cardiac function of rats after myocardial infarction and action mechanism

Objective To investigate the effect of rheum offcinale baill on cardiac function of rats after myocardial infarction and the action mechanism. Methods Rats were randomly divided into sham operation group, myocardial infarction group and rheum offcinale baill administered group (experimental group), 20 rats in each group. The myocardial infarction model was induced by left anterior descending branch ligation. The left ventricular ejection fraction (LVEF) and left ventricular end-diastolic dimension (LVEDD) were measured by ultrasound cardiogram, the apoptosis index of myocardiocytes was measured, and the content of tumor necrosis factor-α (TNF-α), C-reaction protein (CRP), superoxide dismutase (SOD), and malondialdehyde (MDA) in plasma were determined. Results In myocardial infarction group and experimental group the LVEF [(39.42±4.37)% (P=0.002) and (55.24±5.02)% (P=0.000)], and fractional shortening [FS, (18.32±3.12)% (P=0.000) and (27.29±3.54)% (P=0.004)] were decreased as compared with those in sham group [(72.38±5.67)% and (43.25±4.16)%] ; the LVEDD [(0.84±0.13) mm (P=0.000) and (0.66±0.23) mm (P=0.009)] and apoptosis index of the myocardiocytes [(19.4±2.25)% (P=0.000 and (12.50±2.58)% (P=0.007)] were increased as compared with those in the sham group [(0.49±0.21) mm and (4.60±1.23)%]. In myocardial infarction group and experimental group, the content of TNF-α [(292.10±22.25) ng/L (P=0.000) and (226.15±16.35) ng/L (P=0.000)], CRP [(2 152.68±152.05) μg/L(P=0.004) and (1 769.41±123.49) μg/L (P=0.023)] and MDA [(13.23±1.08) mmol/L (P=0.006) and (10.42±0.97) mmol/L (P=0.021)] were increased, and the content of SOD [(90.48±8.13) U/ml (P=0.001) and (129.42±11.17) U/ml (P=0.012)] were decreased as compared with those in sham group [(156.35±19.63) ng/L, (1 056.29±123.41) μg/L, (7.12±0.57) mmol/L, and (153.31±13.05) U/ml]. In addition, the LVEF and FS were higher in experimental group then in myocardial infarction group, and the LVEDD was reduced. Furthermore, the apoptosis index of myocardiocytes and the content of TNF-α, CRP and MDA were decreased in experimental group, and the content of SOD was increased as compared with those in myocardial infarction group. Conclusion After myocardial infarction, the left ventrice expands and the heart function decreases in rats, while the myocardiocyte apoptosis index, the levels of oxidative stress and inflammatory cytokines rise respectively. The rheum offcinale baill can inhibit ventricular enlargement and improve left ventricular systolic function, which may be related to the fact that rheum offcinale baill could restrain the occurrence of myocardiocyte apoptosis, inhibit levels of oxidative stress, and eliminate inflammatory cytokines. Key words: Myocardial infarction; Rheum offcinale baill; Inflammatory factors; Oxidative stress