topical and intradermal efficacy of photodynamic therapy with methylene blue and light-emitting diode in the treatment of cutaneous leishmaniasis caused by leishmania braziliensis

introduction: the topical and intradermal photodynamic therapy (pdt) effect of methylene blue (mb) using light-emitting diode (led) as light source (mb/led-pdt) in the treatment of lesions of american cutaneous leishmaniasis (acl) caused by leishmania braziliensis in hamsters were investigated. methods: hamsters were infected in the footpad with 4×107 promastigotes of l. braziliensis and divided in 4 groups: control group was not treated, amb group was treated with amphotericin b, mb-id group received intradermal mb at the edge of the lesion and mb-tp group received mb topic. after treatment with mb, the animals were illuminated using red leds at the 655 nm wavelength for 1 hour. the mb/led-pdt was carried out three times a week for 12 weeks. results: animals of mb-tp group presented lesion healing with significant diminution in extent of the lesion, and reduced parasite burden compared to control group; however, no significant difference was seen compared to the amb group. mb-tp group also showed reconstitution of the epithelium, the formation of collagen fibers, organization in the epidermis, a little disorganization and inflammation in the dermis. mb-id was ineffective in all parameters evaluated, and it was comparable to the control group results. conclusion: these data show that pdt with the use of mb-tp and led may be an alternative for the treatment of acl. however, additional studies are being conducted to assess the potential of mb/led-pdt, alone or in combination with conventional therapy, for the treatment of acl.