Dexametasona e ivermectina na estrongiloidíase experimental : aspectos parasitológicos e alterações morfofuncionais no trato gastrintestinal de camundongos

Abstract

Dexamethasone is an immunosuppressive glucocorticoid and ivermectin is the antiparasitic of choice for strongyloidiasis. Experimental models using Strongyloides venezuelensis with compromised immunity can be used to understand the parasitehost relationship, as well as unravel the role of the gastrointestinal tract in this relationship. The objective was to evaluate the effects of dexamethasone and ivermectin on the gastrointestinal parasitological and morphofunctional aspects during experimental strongyloidiasis. BALB/c mice were randomly assigned to seven groups: Control (received saline and not infected); Sven (untreated and infected with S. venezuelensis); Dexa 2mg/Kg -SC (treated and uninfected); Sven+Dexa (treated and infected with S. venezuelensis); IVM 200 μg /Kg -VO (treated and uninfected); Sven+IVM (infected with S. venezuelensis and treated with ivermectin); Sven+Dexa+IVM (infected with S. venezuelensis, treated with dexamethasone and ivermectin). Daily, there was weighing and counting of eggs per gram of feces. Weekly, feed intake, feed efficiency, faecal moisture, oro-anal transit time (TTOA) and fecal pellet elimination rate (TEPF) were determined by the Alternating Current Biosusceptometry (BAC) method. Adult worms were recovered from the intestine and organs, including lymphoids, were analyzed. All data were analyzed by ANOVA followed by Dunnett (p<0.05). The groups of animals that received dexamethasone showed reduced food consumption and weight, consequently, presenting negative feed efficiency. The Sven+IVM group showed a significant reduction in OPG only with the administration of 4 consecutive doses. Animals that received dexamethasone had a higher number of eggs eliminated by the end of the experiment, even when ivermectin (Sven+Dexa+IVM) was associated. Animals treated with ivermectin showed accelerated transit when compared to Control. Both drugs altered gastrointestinal motility, as well as the weight of lymphoid organs, relative length of the small intestine, size of the stomach and cecum, and stool moisture. Thus, understanding the effects of these drugs alone or in combination on parasitic infection and GI motility is important to determine the most appropriate therapeutic choices in each situation.