Oral administration of L-arginine prevents congestive heart failure in murine viral myocarditis

It was previously demonstrated that administration of the nitric oxide synthase inhibitor N-G-nitro-L-arginine methyl ester (L-NAME) aggravated viral myocarditis in mice. In the current study, the effects Of L-arginine, a precursor of nitric oxide, on congestive heart failure (CHF) in myocarditis were evaluated. Dietary L-arginine and L-arginine Plus L-NAME (L-arginine + L-NAME group) were administered to encephalomyocarditis virus-infected BALB/c mice over 4 weeks (experiment I) and to encephalomyocarditis virus-infected DBA/2 mice from the 4th through 12th weeks after the virus inoculation (experiment II). An infected control was prepared in each experiment. In experiment I, survival was higher in the L-arginine group compared with the other two groups, and cardiac damage was less, as was incidence of CHF. In addition, extravasated fibrin was less prominent in the L-arginine group. Plasma concentrations of L-arginine and nitric oxide were elevated in the L-arginine group. In experiment II, plasma cardiomyopathic lesions in the L-arginine group were less prominent and were associated with lower plasma catecholamine and lower myocardial collagen concentrations compared with the other two groups. L-arginine treatment may be effective in preventing the development of CHF in viral myocarditis by modifying postmyocarditic architectural remodeling.