Experimental Chagas Disease Model

T. cruzi (Y strain) [30 ], belonging to the TcI lineage [31 (link)], was kindly provided by Dr. Paulo Araújo, Campinas State University, Brazil, and was maintained by weekly intraperitoneal (i.p.) inoculation of 2 × 10⁵ trypomastigote forms on Swiss mice. For experiments, blood was obtained by cardiac puncture with heparinized syringes and needles. Trypomastigote forms were enumerated in a hematocytometer, and 5 × 10³ forms were injected i.p. in mice. Aminoguanidine (AG, selective iNOS inhibitor) [32 (link)] and nonspecific NOS inhibitor L-nitroarginine methyl ester (L-NAME) [33 (link)] (Sigma-Aldrich, St. Louis, MO, USA) were diluted in sterile phosphate buffer saline (PBS pH 7.2). All solutions were freshly prepared, under sterile conditions.