Application of cardiac gated magnetic resonance imaging in murine Chagas' disease

To evaluate the role of gated cardiac magnetic imaging resonance (MRI) in C hagas' disease, we infected mice with Trypanosoma cruzi (Brazil strain). Tw o models were chosen for study, the CD1 and the inducible nitric oxide synt hase knockout (NOS2(-/-)) mice. Infection of CD1 mice was associated with a significant increase in the right ventricular inner diameter (RVID) that w as reversed in some mice by verapamil. Expression of cardiac NOS2 has been associated with myocardial dysfunction. Therefore, we evaluated chagasic ca rdiomyopathy in NOS2(-/-) and syngeneic wild type (WT) mice. Infected WT mi ce exhibited an increase in RVID in the acute phase (< 60 days postinfectio n) that was more marked during chronic infection (> 100 days postinfection) . Chronically infected NOS2(-/-)mice had an increase in RVID. The RVID in i nfected WT mice was greater than in NOS2-/- mice. These data demonstrate th at MRI is a useful tool in the serial evaluation of the heart in murine Cha gas' disease. In addition, it supports the notion that the NOS2(-/-)/NO pat hway may contribute to the pathogenesis of murine chagasic cardiomyopathy.