Uso de microscopia de força atômica como modelo de estudo em atividades parasitárias e efeito do ácido anacárdico em formas epimastigota e tripomastigota de Trypanosoma cruzi

Abstract

This work it is divided into two parts: the first describes methodologies for the preparation of Trypanosoma cruzi samples in atomic force microscopy (AFM), due to the difficulties encountered in obtaining images of studies of new therapeutic targets, the second part presents the effect of anacardic acid in T. cruzi. To obtain images of AFM, two methodologies were used to prepare samples, using the same protocol for SEM, and the other using glutaraldehyde only and washing with water and PBS. The forms of the parasite used were epimastigotes of T. cruzi without treatment and treated with Benzonidazole. The results showed that parasites prepared only with glutaraldehyde and washed with water and PBS preserved the structure of the parasite and, in addition, it was possible to make images with parasites treated with BZN, however, when using the same protocol of the SEM, changes were observed in parasite structure that may have been caused by excessive hydroalcoholic washes. It can be concluded that this new approach to sample preparation may collaborate with studies of other forms of the parasite, as well as to investigate the action of new therapeutic targets for treatment of the disease. Anacardic acid is one of the main liquids contained in cashew nuts (CNSL) and has presented several important biological applications, among them glycosomal protein inhibitor GAPDH (glyceraldehyde-3-phosphate dehydrogenase). With this, seeks out for new alternatives for the treatment of Chagas' disease because it is a neglected disease. This work aimed to investigate the effect of anacardic acid (15:0) on epimastigotes and trypomastigotes of T. cruzi, as well as to evaluate the cytotoxic effect of anacardic acid in mammalian cells (LLC-MK2). The results showed that anacardic acid was able to decrease viability in LLC-MK2 cells at concentrations greater than 400 and 200 μM after 24 h of treatment with an IC50 of 135,6 μM; in the epimastigote forms the inhibitory effect occurred at concentrations of 200, 100 and 50 μM (after 24 h of incubation), 100 and 200 μM (after 48 and 72 h of incubation); already, for trypomastigote forms, the results demonstrated a total inhibition at the concentration of 200 μM. Anacardic acid had an inhibitory effect both in epimastigote forms and in trypomastigote forms of T. cruzi.