Enhancement of amlodipine cardioprotection by quercetin in ischaemia/reperfusion injury in rats

To investigate the possible modification of the cardioprotective effect of amlodipine when co-administered with quercetin in myocardial ischaemia/reperfusion-induced functional, metabolic and cellular alterations in rats. Oral doses of amlodipine (15 mg/kg) and quercetin (5 mg/kg), alone or in combination, were administered once daily for 1 week. Rats were then subjected to myocardial ischaemia/reperfusion (35min/10min). Heart rates and ventricular arrhythmias were recorded during ischaemia/reperfusion progress. At the end of reperfusion, activities of plasma creatine kinase (CK) and cardiac myeloperoxidase were determined. In addition, cardiac contents of lactate, ATP, thiobarbituric acid reactive substances (TBARS), reduced glutathione (GSH) and total nitrate/nitrite (NOx) were estimated. Finally, histological examination was performed to visualize the protective cellular effects of different pretreatments. Combined therapy provided significant improvement in the amlodipine effect toward preserving cardiac electrophysiologic functions, ATP and GSH contents as well as reducing the elevated plasma CK, cardiac TBARS and NOx contents. Quercetin could add benefits to the cardioprotective effect of amlodipine against injury induced in the heart by ischaemia/reperfusion.