RESUMO
BACKGROUND: Leishmaniasis is a common zoonotic disease that is transmitted by phlebotomus and causes several clinical conditions, from self healing lesion to deadly internal organ involvement. Photodynamic therapy (PDT) is a treatment method that leads to the generation of cytotoxic species and consequently to cell death and tissue destruction by visible light in the presence of a photosensitizer and oxygen. The aim of this study was to investigate effect of malachite green (MG)-mediated PDT in Leishmania tropica (L. tropica) promastigotes. MATERIAL AND METHODS: Parasites were incubated with 0.19, 0.39, 1.56, 3.25 and 6.25 µM of MG for one hour and subjected to 46.4 J/cm2 light irradiation. Trypan blue assay was used to evaluate the viability of the cells and mitochondirial activity alteration was determined by MTT. Morphological changes were analyzed by Giemsa staining and Scanning electron microscopy (SEM) analyses. Flow cytometry was used to quantify the fluorescence emitted by cell volume, JC-1, Cell Cycle and Annexin V/PI staining reagents. RESULTS: Malachite green mediated photodynamic therapy at 1.56 and 3.125 µM decreased the viability of the L. tropica promastigotes and induced changes in the mitochondrial membrane potential. L.tropica promastigotes was bloked in G0/G1 phase. The morphology of the parasite was affected at the 1.56 and 3.125 µM MG+PDT, resulting in rounded cells with loss of flagellum and irregular shape. CONCLUSIONS: This study demonstrated that antileishmanial effects through mitochondrial dysfunction, cell cycle arrest, and apoptosis-like cell death to parasites. This work showed PDT with MG effectedparasites. Therefore, MG-mediated PDT may provide a promising approach for L. tropica promastigotes.