Leishmanicidal effect of antiparasitic photodynamic therapy-ApPDT on infected macrophages

The aim of this study is to evaluate the effects of ApPDT (antiparasitic photodynamic therapy) on the interaction of Leishmania braziliensis with J774 macrophages, used as a photosensitizer, methylene blue associated with red laser. The tests are in triplicate and the samples divided into four groups: control, photosensitizer, laser, and ApPDT. The photosensitizer used was the methylene blue at concentration of 12.5 μg/mL. The parameters of the laser were λ = 660 nm, 40 mW, and 8.4 J/cm². Samples are analyzed by optical microscopy through the identification and counting of infected and uninfected macrophages, parasite load, infectivity, and infection index. Statistical analysis used ANOVA test with Tukey post-test, being considered statistically significant p < 0.05. The analysis of the interaction tests shows that the infection rate in the ApPDT group in relation to the control group presents a statistically significant reduction (p < 0.0001) of 71% at both 24 and 48 h (p < 0.0001) of 62%. ApPDT reduces the number of macrophages infected by Leishmania braziliensis, as well as the number of intracellular parasites, being a possible alternative therapy in the treatment of cutaneous leishmaniosis.