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 NG-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.