Protective effect of geniposide on myocardial ischemic reperfusion injury in rats

Objective To explore protective effect of geniposide on myocardial ischemic-reperfusion injury and its mechanism in rats.Methods The myocardial ischemic-reperfusion injury model was made by occluding left coronary artery in rats;then the rats were randomly divided into six groups:pseudo-operation group,ischemic reperfusion(I/R) group,geniposid groups with the dosage of 25,50,and 100mg/kg and a positive control group.The activity of lactate dehydrogenase(LDH) in serum,levels of superoxide dismutase(SOD),maleic dialdehyde(MDA),Ca²⁺-ATPase in myocardial tissues were measured.Myocardial cell apoptosis was marked with terminal-deoxynucleotidyl transferase mediated nick end labeling(TUNEL).The expressions of p53 protein,Bcl-2,and Bax in the myocardial tissues were detected with Western blot.Results Compared with those of the I/R group,significant decreases in LDH(4598.6±638.7 and 4386.9±549.8 U/L)in serum and MDA(2.12±0.47 and 1.63±0.29 nmol/mg.pro) in the myocardial tissues,and significant increases in the concentration of SOD(41.48±3.86 and 43.47±3.88NU/mg.pro) and Ca²⁺-ATPase(0.71±0.11 and 0.72±0.130 mol/mg.h) in the myocardial tissues were observed in the rats treated with geniposid at the dosages of 50 and 100 mg/kg,respectively(all P<0.05).Compared to I/R group,geniposid could promote apoptosis of myocardial cells,with the apoptosis rates of 12.3±1.8% and 11.2±1.6% for the rats treated at the dosages of 50 and 100 mg/kg(both P<0.05).The expressions of p53(1.71±0.35 and 1.62±0.5),Bax(0.95±0.24 and 0.89±0.19)were down-regulated for the rats of geniposid groups at the dosages of 50 and 100 mg/kg(all P<0.05)and the expression level of Bcl-2(0.71±0.11 and 0.78±0.17) was up-regulated for the rats of geniposid groups at the dosages of 50 and 100 mg/kg(all P<0.05).Conclusion Geniposide can reduce oxidative stress induced by myocardial ischemia and reperfusion;the mechanism of the effect maybe relate to the inhibition of p53 protein level,increase of Bcl-2/Bax ratio,and decrease of the occurrence of myocardial cell apoptosis.