EFFECTS OF RENUTRITION ON CALORIC-DEFICIENT MICE DURING TRYPANOSOMA-CRUZI INFECTION

Previous work in our laboratory showed that severe caloric deficiencies significantly accelerate death due to infection by T. cruzi and moderate deficiencies of calories affect some parameters of the immune response to the parasite. In the present work, the effects of renutrition on the course of the disease and the immunological parameters affected by the moderately deficient diets, are shown in the same animal model. BALB/c mice were divided into four groups receiving: 6g of laboratory chow during the course of the experiment (C); 3.6g until time of infection and then 6g (REF1); 3.6g until one week post infection and then 6g (REF2); and 3.6g throughout the experimental period (MN). The animals were infected through the i.p. route with 100 blood trypomastigotes two weeks after initiation of dietary treatment. Body weight and parasitemia were checked periodically. Survival rate of REF1 (60%) was significantly higher than MN animals (14.8%) and not significantly different from C animals (68%), while 30% of REF2 animals survived the infection. Onset of parasitemia and death were observed in REF animals earlier than in C animals and later than in MN animals. Renutrition on the chronic phase was studied on animals infected with 50 trypomastigotes, 4 months post infection. Renourished (REF1) animals showed delayed hypersensitivity responses and specific IgG levels as seen by ELISA, which were not statistically different from C (p > 0.1). Furthermore, no differences were seen on histological damage observed between REF and C animals. It can be concluded that refeeding caloric deficient animals increases their survival rate and reverts immunological deficiencies of affected animals.