Análise de macrófagos M1 e M2 em modelo experimental de leishmaniose cutânea submetido à terapia fotodinâmica associada ao ácido 5-aminolevulínico

Abstract

Introduction: Leishmaniasis is an infectious disease caused by parasites of the genus Leishmania. Cutaneous leishmaniasis (CL) is caused by L. major in the old world and by L. braziliensis in the Americas. Considering the targeted organs, photodynamic therapy (PDT) may constitute a valuable therapeutic intervention. Macrophages are the host cells of Leishmania in mamals and may be classified into type M1 or M2 depending on the pattern of activation. In this study, we evaluated the profile of macrophage and the effectiveness of PDT for the treatment of experimental CL. Methods: BALB/c mice were infected in the foot pad with 1 x 106 amastigotes of L. braziliensis and treated with aminolevulinic acid (ALA), visible light, or ALA-PDT. The ex vivo mRNA expression levels of interleukin-10 and arginase-1, and TNF-α and induced nitric oxide synthase (iNOS) was quantitated for the identification of M2 and M1 macrophages, respectively. Results: The parasite load decreased significantly in the groups treated with PDT compared with the other groups. The iNOS levels were higher in the group treated with PDT, but the difference was not significant. Moreover, no significant difference was observed in the expression of the other markers evaluated. Conclusion: Parasite death does not appear to be mediated by the modulation of M1 or M2 macrophages in this experimental model of leishmaniasis treated with ALA-PDT. PDT significantly decreased the parasite load in vivo but did not eliminate parasitism. The increase in the iNOS levels suggests it might participate in the antimicrobial mechanisms triggered by ALA-PDT.