Effect Of Valsartan On Energy Metabolism Of Myocardial Ischemia-reperfusion Injury In Rats

ObjectiveTo observe the effect and the mechanism of Valsartan on myocardial ischemia reperfusion energy metabolism in rats.MethodsFifty SD rats were divided into 5 equal groups randomly:sham-operated group(0.9%normalsaline,2ml/d), ischemia-reperfusion group (0.9%normalsaline, 2ml/d), Valsartan group (Valsartan 30mg·kg^-1·d^-1), Valsartan+ N-nitro-L- argininemethylester(L-NAME) group (Valsartan 30mg·kg^-1·d^-1,L-NAME15mg/kg), L-NAMEgroup(L-NAME15mg/kg). L-NAME was injected from tail vena 15min before ischemia. After 2 weeks of pretreatment,rats were subjected to 30min left -anterior-descending coronary artery occlusion and 120min reperfusion.After reperfusion,The contents of nitric oxide synthase(NOS),adenosine triphosphate (ATP) and the activity of ATPases, Meanwhile, the ultrastructure mitochondria changes in myocardium were observed and Vv, N_A,δof rat heart tissue were detected using stereology method after MIRI.ResultsThe NOS,ATP,ATPases,N_A andδlevels of myocardial tissue were lower and Vv were higher remarkably in ischemia-reperfusion group than those in sham-operatedgroup(P<0.01), Such ultrastructural changes of myocardial mitochondria apparently unusual during MIRI; The NOS(0.554±0.092 vs 0.230±0.075), ATP(5.39±0.55 vs 2.32±0.32), Na⁺-K⁺ATPase(3.47±0.37 vs 2.37±0.32), Ca²⁺-Mg²⁺ATPase(5.65±0.37 vs 4.37±0.35), N_A(0.510±0.02 vs 0.315±0.02),δ(37.49±0.78 vs 27.45±1.02)levels of myocardial tissue were higher and Vv(18.56±0.27 vs 23.07±0.74) was lower remarkably in Valsartan group than those in ischemia-reperfusion group (P<0.01), abnormal changes of the myocardial ultrastructure such as mitochondria in Valsartan group were ameliorated remarkably during MIRI.The NOS(0.314±0.027), ATP(3.46±0.50), Na⁺-K⁺ATPase (2.84±0.26),Ca²⁺-Mg²⁺ATPase (4.63±0.27), N_A(0.412±0.01),δ(34.67±1.11)levels of myocardial tissue were lower and Vv(19.38±0.38) was higher partly in Valsartan+ N-nitro-L-arginine methylester (L-NAME) group than Valsartan group(P<0.05). Each index levels of the L-NAME group were not significantly different from those of the I/R group (P>0.05).Conclusions1. Valsartan can improve myocardial cell energy metabolism in the reperfusion injury after myocardial ischemia.2. L-NAME of NOS blockers play some antagonist role in its process, NOS-NO may be one of the path-ways.