Combined simvastatin–manidipine protect against ischemia–reperfusion injury in isolated hearts from normocholesterolemic rats

This study investigated whether oral simvastatin and manidipine interact in protecting the perfused rat heart from ischemia–reperfusion damage. Simvastatin (0.3 to 3  mg/kg) and manidipine (1 to 10 mg/kg) were given orally singly or together to normocholesterolemic rats once a day for seven consecutive days. At the end of treatment, systolic blood pressure and heart rate were measured in conscious rats, and the lipid profile and other biochemical markers, such as thromboxane B2, nitrite/nitrates and 6-keto-prostaglandin F1α (6-keto-PGF1α) were determined in the plasma. Hearts were then isolated, perfused with Krebs–Henseleit, and subjected to low flow ischemia–reperfusion injury. Post-ischemic recovery of left ventricular function was measured as left ventricular developed pressure and left ventricular end-diastolic pressure. Creatine kinase, lactate dehydrogenase, tumor necrosis factor-alpha and 6-keto-PGF1α were measured in the heart effluents. In conscious animals, simvastatin alone increased plasma 6-keto-PGF1α release while manidipine alone reduced systolic blood pressure with a slight sympathetic reflex increase in heart rate, and increased plasma nitrite/nitrates. The combined treatment produced the same effects, but significantly more marked, and accompanied by a significant reduction of thromboxane B2. Combined treatment was also significantly more effective than the single drugs in protecting the hearts from ischemia–reperfusion injury, with inhibition of creatine kinase, lactate dehydrogenase and tumor necrosis factor-alpha, and enhancement of 6-keto-PGF1α during reperfusion. These data show that simvastatin and manidipine interact positively in protecting the rat heart from ischemia–reperfusion injury, possibly through increased prostaglandin and nitric oxide formation by the vascular endothelial cells.