Efeito in vitro e in vivo do probiótico Lactobacillus rhamnosus sobre larvas de Toxocara canis

Abstract

Visceral toxocariasis is a parasitic zoonosis worldwide neglected, whose control is difficult, by the complexity of nematode biology Toxocara canis, main etiologic agent and the treatment with drugs have moderated efficacy. Experimental studies with probiotics have shown promising results to control this parasitosis, but there is necessity to test a probiotic that is easily administred and safe for human consumption. This study aimed to evaluate the effect of probiotic Lactobacillus rhamnosus ATCC 7469 on the parasite load in BALB/c mice with acute toxocariasis. Two groups (G) were formed by 10 mices, as G1 received probiotic Lactobacillus rhamnosus ATCC 7469 at a concentration of 1.109 colony forming units (CFU), by intragastric gavage (IG), 15 days pre-inoculation and two days after the inoculation of 100 T. canis eggs, via IG. The mice of G2 (control) received daily sterile culture medium de Man, Rogosa and Sharpe (MRS), by the same administration route, and during the same period of G1. The Evaluation consisted in quantifying the larvae recovered by tissue digestion technique of organs and skeletal striated muscle. While the in vitro test of probiotic was realized in the concentrations 1.106, 1.107, 1.108, 1.109 UFC 100 larvae per hole of the microculture plate (triplicated). The administration of probiotics reduced the parasite load of T. canis larvae in 53.3% (p = 0.0018) in the early stage of infection in mice. In the in vitro test, probiotic showed no direct effect on larvae of T. canis, and 89.3% to 93.5% of the larvae remain viable at different concentrations. These results show the potential of probiotic L. rhamnosus in promoting the reduction of parasite load of T. canis larvae in mice, it is important to study the action mechanism of this probiotic.