Chlorin E6 phototoxicity in L. major and L. braziliensis promastigotes-In vitro study

Background: Cutaneous leishmaniasis is a zoonosis caused by protozoa of the genus Leishmania. Conventional treatments are long and aggressive, and they trigger a diversity of side effects. Photodynamic Therapy was originally proposed as a treatment for cancer, and it now appears to be a promising therapy for local treatment with fewer side effects of infectious diseases. Methods: This study aimed to evaluate Chlorin e6 internalization by Leishmania major and Leishmania braziliensis promastigotes and its viability and effects on mitochondrial activity. Control groups were kept in the dark, while PDT groups received fluence of 10 J/cm(2) (660 nm). Chlorin internalization was evaluated using confocal microscopy after one hour of incubation for both species. Results: The mitochondrial activity was evaluated by MTT assay, and viability was measured by the Trypan blue exclusion test. Giemsa staining was used to observe morphological changes. PS was internalized in both species and mitochondrial activity changed in all groups. However, the obtained MTT and Trypan results indicated that despite the change in mitochondrial activity in the dark groups, their viability was not affected, whereas the PDT treated groups had significantly reduced viability. Morphology was drastically altered in PDT treated groups, while groups kept in the dark exhibited the standard morphology. Conclusions: This study demonstrates that Chlorin has great potential for being used in PDT as a treatment for cutaneous leishmaniasis, although more studies are needed to determine in vivo application protocols. (C) 2016 Elsevier B.V. All rights reserved.