Dihydroxyflavonol reduces post-infarction left ventricular remodeling by preventing myocyte apoptosis in the non-infarcted zone in goats

Background Myocyte apoptosis is considered to be the major causative factor of left ventricular (LV) remodelingfollowing myocardial infarction (MI).We previously reported that 3’,4’-dihydroxyflavonol (DiOHF),was able to suppressoxidative stress and preserve the expression of endothelial nitric oxide synthase during myocardial reperfusion injury,which may benefit the reduction of myocyte apoptosis.We therefore aimed to evaluate the potential actions of DiOHFagainst myocyte apoptosis and post-infarction LV remodeling in this study.Methods Following experimental MI,surgical instrumented goats were randomly assigned into vehicle and DiOHF (2mg/kg;i.v.,daily) groups to receive 4 weeks of reperfusion with corresponding treatments.LV pressure recordings andechocardiogram were performed at baseline,2 and 4 weeks of reperfusion.Myocardial tissues were collected in the endto determine infarct size and apoptosis related assays.Results LV end-diastolic volume and diameter were significantly increased 4 weeks after MI in the vehicle group,accompanied by reduced posterior wall thickness,septal thickness and LV mass,whereas those changes were markedlyprevented by DiOHF treatment.Similarly,significantly reduced infarct size was found in DiOHF group as compared tovehicle group,and DiOHF dramatically inhibited the increase in LV end-diastolic pressure and the reductions in ejectionfraction,fraction shortening and dP/dtmax.Moreover,DiOHF treatment significantly reduced the extent of myocyteapoptosis detected by TUNEL assay,enhanced the protein expression of caspase-3,Fas,Bax and cytochrome c in thenon-infarcted myocardium in comparison to vehicle.Conclusions Daily DiOHF treatment during the reperfusion period after MI in the ovine hearts markedly reduced themagnitude of post-infarction LV remodeling through the inhibition of myocyte apoptosis in the remote non-infarctedmyocardium.