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/cm. 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.
Cancer is a pathology characterized by increased cell progression and/or reduced programmed cell death. Melanoma shows a rapid increase in cell progression and its resistance to chemotherapy is associated with uncontrolled apoptosis and to mechanisms that increase the flow of the drug out of the cell. The objective of this study was to evaluate the effects of photodynamic therapy (PDT) on the cell proliferation and cellular alterations in B16F10 murine melanoma. For that, four experimental groups were evaluated: the control group; laser group (ʎ = 660 ηm, 40 mW, 2.4 J/cm); photosensitizer group (solution containing methylene blue and toluidine blue 1:1-12.5 μg/mL); PDT group. The incubation time was 30 min. Fluorescence microscopy assays were performed without fixation with the DAPI, monodansylcadaverine (MDC), and dihydroethidium (DHE) probes. Cell proliferation was also determined at 24-h time. The tests were performed in triplicate and the statistical test used was ANOVA with Tukey post-test. The results demonstrate that the plasma membrane of the cells of all the experimental groups remained intact, ROS production and autophagy significantly increased (p < 0.0005 and p < 0.0071, respectively) only in the PDT group. The cell proliferation essay showed a reduction of 74.2% on the PDT group in relation to the control group. The present study demonstrated that oxidative stress promoted by photodynamic therapy may induce autophagy and consequently reduce cell proliferation in B16F10 melanoma.
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