[Influence of free radicals on Trichinella spiralis infection in mice].

The aim of the study was to examine the influence of free radicals: nitric oxide (NO), hydrogen peroxide (H202) and superoxide anion (O2-) on Trichinella spiralis infection in mice. The studies were performed on two strains of mice: C57BL/6 and BALB/c, which differ in immunological response to T. spiralis infection. Also the influence of AG--inhibitor of inducible nitric oxide synthase (iNOS) administered in the first days after T. spiralis infection (1-5 dpi) on the cytotoxic immune response and 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 cytotoxic immune response and the number of muscle larvae was studied. Activation of macrophages can cause pathology. Contact of macrophages with antigens stimulates these cells to produce, among others, highly reactive inorganic compounds. There are free radicals: NO, H2O2 and O2-. NO, O2-, and their metabolites are highly toxic for most pathogens, including parasites. However, little is known about their role in the defense against T. spiralis infection. The performed studies have proved, that free radicals play role in the host immune response during both intestinal and muscle phase of T. spiralis infection in mice. In the intestinal phase of the T. spiralis infection cytotoxic immune response is activated in mice peritoneal cavity and in the muscle phase, the local immune response activated in the neighborhood of larvae in muscles appeared as the higher level of free radicals in blood and urine. Administration of AG between 1-5 dpi causes opposite reactions in two different strains of mice. In BALB/c mice AG causes fast expulsion of adult T. spiralis from the intestine but in C57BL/6 mice the expulsion of parasites is slower after AG. However, there are no differences between two strains of mice after treatment with AG between 16 and 29 dpi. AG causes diminution of larvae in muscles of both BALB/c and C57BL/6 mice. Inflammatory response in peritoneal cavity is observed later during the infection in "low responders" (C57BL/6) mice in comparison with "high responders" (BALB/c) mice. Thl like mice (C57BL/6) react stronger to AG treatment than Th2 like mice (BALB/c). It occurs as changes and fluctuations in free radicals levels and the number of peritoneal cells after AG treatment in C57BL/6 mice. Weak or no reaction on AG injections in BALB/c mice is responsible for more stabile and more sufficient defense response of the host to T. spiralis infection.