Efeito da terapia com laser de baixa potência (LBP) em modelo experimental de fibrose pulmonar idiopática (FPI)

Abstract

Pulmonary idiopathic fibrosis is one of the most usual intersticial diseases with great impact on life quality of patients. With both environmental and genetic factors involved, it has poor prognosis and unfortunately no effective treatment. Several experimental models have been proposed with the aim to better understand the mechanisms involved, and also for the stablishment of an effective therapy. Low level laser therapy is relatively new but may be considered a promising approach for chronic inflammatory diseases, with very low cost and no adverse effects. Some researches have already demonstrated the efficacy of such therapy on lung diseases, whose inflammatory parameters were reduced, mainly due to na increase in anti-inflammatory citokines. Thus, at the presente research we evaluated the effect of low level laser irradiation on both inflammatory and structural cells of the lung after bleomycin-induced lung fibrosis. For that, eighteen male C57Bl/6 mice were separated in three groups: Basal (n=5), Fibrosis (n=6) and fibrosis + Laser (n=7). Animals were anesthetized with ketamina and xilazina and received one dosis of bleomycin at 1,5U/Kg by orotraqueal. Fourteen days later, experimental groups received laser irradiation for seven days oce a day. Twenty-four hours later, all animaiswere euthanized and bronchoalveolar lavage fluid was obtained. Total cells were counted on Neubauer chambers and followed by cytospin staining with DiffQuick. Three hundred cells were counted per slide. Further, pulmonary tissue was fixed in formaline 10% for twenty-four hours and included in paraffin and submitted to H&E staining for histopathological analysis. Culture of type II pneumocytes, epithelial cells and fibroblasts were also obtained and, after treatment with bleomycin, cells were irradiated or not wthlow level laser. Several citokines were evaluated, as IL-1β,IL6, TNF-α,TGF-β, IL-10,IL-17, INF, 1/kC by ELISA. Our results demonstrate that laser irradiation significantly reduces lung inflammation, evidenced by reduced celullar infiltrate in the lavage, as well as for the reduction in of IL-1β, IL-6, IL-10, IFN- g, TNF-a and KC. Thus, our findings corroborate the idea of low level laser as beneficial for the treatment of lung interstitial diseases.