Inhibition of nitric oxide production by aminoguanidine influences the number of Trichinella spiralis parasites in infected "low responders" (C57BL/6) and "high responders" (BALB/c) mice.

The influence of nitric oxide (NO) on the development of adults and larvae Trichinella spiralis was examined in two strains of mice: C57BL/6 and BALB/c. The influence of aminoguanidine (AG)-inhibitor of inducible nitric oxide synthase (iNOS) administered in the first days after T. spiralis infection (1-5 dpi) on the number of adult parasites, as well as the influence of AG administered at the beginning of muscle phase of the T. spiralis infection (16-29 dpi) on the number of muscle larvae, was studied. In mice that were treated with AG from the 1st to the 5th day post infection (dpi), the numbers of adult T. spiralis were counted in intestines at 6, 9, 15, and 20 dpi. In this experiment, the impact of AG expressed as diminution of adult worms at 9, 15, and 20 dpi in BALB/c mice. The opposite effect of AG was demonstrated in C57BL/6 mice at 6 and 9 dpi. In mice in which AG was applied from the 16th to the 29th dpi T. spiralis larvae were counted at 30, 35, and 41 dpi. This experiment demonstrated that treating mice with AG at the beginning of muscle phase of the infection inhibits the reduction of muscle larvae number in mice of both strains.