Efeitos do laser de baixa potência in vivo na ativação de neutrófilos na paracoccidioidomicose experimental murina

Abstract

Innate immunity is an important component of host defense against by fungi, and into this context macrophages and neutrophils (PMN) play a central role in paracoccidioidomycosis. The treatment of this disease includes the use of antifungals that, which in addition to the prolonged administration time needed may have many side effects, so research for more efficient drugs or adjuvant treatments is needed. Low level laser therapy (LLLT) has been used as adjuvant treatment for many ailments, and its modulating effect on immune cells has already been demonstrated. In this work, we evaluated the effects of LLLT (λ= 780 nm e 50 mW) applied “in vivo” in alternate days at two points of hind paws of Swiss mice inoculated in the subcutaneous air pouch with the virulent P. brasiliensis Pb18 isolated or with Zymosan. Unirradiated animals were used as controls. After 10 days of infection we obtained a highly pure population of PMN, which subsequently were maintained in culture in presence of Pb18 for trials to protein production, evaluation of mitochondrial activity, production of reactive oxygen species (ROS) and quantification of viable fungi. The results showed that PMN from irradiated animals, regardless of the “in vivo” stimulus for their obtention, presented higher production of ROS, elevated mitochondrial activity and increased fungicidal capacity. Regarding the production of proteins, PMN from unirradiated animals showed increased production, while the treated group decreased gradually this production with the time of incubation. We conclude that LLLT renders PMN more active metabolically, resulting in higher fungicidal activity against Pb18, probably due to increased production of ROS, independently of the stimulus used to obtain it.