Trypanosoma cruzi: biotherapy made from trypomastigote modulates the inflammatory response

This study evaluates the effect of Trypanosoma cruzi biotherapy 17dH (BIOT) on mice of different ages, infected with the protozoa concerned.

Performing a blind, controlled, randomized by drawing experiment, 110 animals four or eight-week-old, Swiss, male mice were divided into infected control treated hydroalcoholic 7% (CI-4 = 34 or CI-8 = 21 animals) and infected control treated with biotherapy 17dH-0.2 mL/animal/20 consecutive days/oral regimen (BIOT-4 = 33 or BIOT-8 = 21 animals). Animals were inoculated intraperitoneally with 1400 trypomastigote, T. cruzi Y-strain. Parasitological, immunological and histopathologic parameters were evaluated statistically, using Statistica-8.0 and R 3.0.2 program to analysis of survival. The study was approved by the Ethics Committee for Animal Experimentation/UEM.

Four-week-old mice showed no statistical difference in parasitemia (P = 0.5718) between the treated and control group. Eight-week-old mice from the treated group had a higher parasite peak (P = 0.0424) and higher parasitemia (P < 0.005) than the control. To both groups of 4 and 8 weeks of age, treated or untreated, survival of mice was higher in the treated group than in the control, although it was not statistically significant (p-value = 0.32, 0.55 respectively). Four-week-old mice displayed a spleen section with a number of amastigote nests significantly higher in BIOT-4 than CI-4 (P = 0.01). In eight-week-old mice the number of amastigote nests (P < 0.001) and inflammatory foci (P < 0.06-10% significance) in the liver section were smaller in BIOT-8 than CI-8. Spleen giant cells were significantly higher in CI-8 than in BIOT-8 (P < 0.01). Eight-week-old animals treated with biotherapy showed higher parasitemia and lower tissue parasitism. Opposite pattern was observed in four-week-old animals.

There is a difference of high diluted medication effect in four and eight-week-old mice. In the group of animals 8 weeks the immunomodulatory effect seems to have been higher. Hence, treatment with the medicine produced from T. cruzi modulates the inflammatory response with increased apoptosis and decreased serum levels of TGF-β.