Cardioprotective Effect of Polymyxin-B and Dantrolene Combination on Isoproterenol-Induced Hypertrophic Cardiomyopathy in Rats, via Attenuation of Calmodulin-Dependent Protein Kinase II

Hypertrophic cardiomyopathy is a major cause of mortality worldwide. In this study, we hypothesized that the combination of Dantrolene and Polymyxin-B will provide cardioprotective action against isoproterenol-induced hypertrophic cardiomyopathy via attenuation of Calmodulin-dependent protein kinase II (CaMKII). Hypertrophic cardiomyopathy was induced in rats by subcutaneous administration of isoproterenol (5 mg/kg) for 14 days. Simultaneously, animals were treated with Polymyxin-B per se, Dantrolene per se, and Dantrolene and Polymyxin-B combination for 14 days. Hemodynamic parameters, biochemical parameters, and histological analysis were performed. Administration of isoproterenol for 14 days resulted in severe myocardial damage, characterized by cardiac hypertrophy and increase serum CK-MB, CK-Nac, LDH, AST, and ALT levels. It also caused alteration in electrocardiogram and blood pressure. A significant increase in CaMKII was observed in heart homogenate. Treatment with the Polymyxin-B and Dantrolene combination significantly ameliorated cardiac hypertrophy, biochemical parameters, ECG parameters, and heart histopathology. Further, significant attenuation in CaMKII levels was observed. The effect of the combination was more than per se treatment. Results of the current study showed that the combination of Polymyxin-B and Dantrolene prevented the development of isoproterenol-induced hypertrophic cardiomyopathy in rats via attenuation of the CaMKII.