Cardioprotective effects of Viscum album L. ssp. album (Loranthaceae) on isoproterenol-induced heart failure via regulation of the nitric oxide pathway in rats

OBJECTIVE Viscum album L. has favorable cardiovascular effects including antihypertensive and vasorelaxant activity, and the nitric oxide (NO) pathway upregulation has been proposed to be the underlying mechanism. NO also plays an important role in the pathophysiology of heart failure. However, its effects on cardiac systolic function are unclear. METHODS A total of 30 male Wistar albino rats at 12 weeks of age were randomly divided into three groups: control, isoproterenol-induced heart failure group (ISO), and isoproterenol-induced heart failure + V. album treatment group (VA) groups (n=10 in each group). V. album was orally given at a dose of 250 mg/kg/day by gavage. Parameters of heart failure were compared among the groups. Tamhane's T2 test, paired sample t-test, and Bonferroni methods were used for statistical analysis. RESULTS V. album resulted in an improvement in all parameters of heart failure including left ventricular diameters (6.34±0.23 mm, 6.98±0.35 mm, and 6.71±0.10 mm for left ventricular end-diastolic diameter in control, ISO, and VA groups, respectively, p<0.05), ejection fraction (73.3±3.1%, 56.7±2.6%, and 65.2±1.5% for control, ISO, and VA groups, respectively, p<0.05), serum NT-proBNP levels, and histopathological changes. V. album treatment resulted in a statistically significant attenuation of increased levels of NO and iNOS (p<0.0001). The levels of hs-CRP were also found to be lower in the VA group compared with the controls and ISO groups (p<0.01). CONCLUSION V. album exerted favorable effects on left ventricular function in isoproterenol-induced heart failure rats. Upregulation of the NO pathway seems to be the possible pathophysiological mechanism. Favorable vascular outcomes can also be speculated considering the reduction in serum hs-CRP levels.