Estudo dos efeitos anti-inflamatórios da terapia com laser de baixa intensidade (LBI) sobre a inflamação alérgica pulmonar: participação dos leucotrienos

Abstract

Asthma affects a significant portion of the population with high social and economic cost. According to Ministry data of Health of Brazil, asthma ranks fourth in hospitalizations in the Unified Health System. Low level laser therapy (LLLT) is a new therapy that shows efficacy in lung diseases to reduce inflammatory parameters, with low cost and without side effects. Studies leukotriene receptor antagonists, such as montelukast (MK) have contributed at different levels for the treatment of asthma as well as the use of 5-lipoxygenase inhibitors (zileuton - ZIL). Thus, this study aimed to evaluate the effects of LLLT therapy and its combination with MK and ZIL in an experimental model of chronic lung allergic inflammation induced by ovalbumin (OVA). Balb/c mice were divided into 10 groups: Basal, LLLT, MK, ZIL, OVA, OVA + LLLT, OVA + MK, OVA + ZIL, OVA + LLLT + MK, OVA + LLLT + ZIL. The chronic allergic pulmonary inflammation was induced by SC immunization of ovalbumin (OVA) mixed with alum (day 0 and day 14) and tracheal challenge with OVA (three days / week for five weeks). The OVA + LLLT group was irradiated (laser diode 660nm, 30mW and 3J), OVA + MK was treated with sodium montelukast (5mg / kg) by gavage, OVA + ZIL was treated route (ip) with zileuton (10mg / kg), the OVA + LLLT + MK group was treated with MK and LLLT. As the OVA + LLLT + ZIL group was treated with ZIL and LLLT. Twenty-four hours after the last treatment, the animals were anesthetized, tracheotomized, cannulated and bronchoalveolar lavage collected and analyzed (total and differential count of the cells and cytokine levels in bronchoalveolar lavage fluid by ELISA technique). Both treatments reduced the total number of cells and eosinophils in bronchoalveolar lavage (BAL) (p<0.001). Using LLLT there was a reduction in the production of IL-4 (p<0.05) However, the concurrent treatments reduction was more significant (p<0.01), decreased significantly (p<0.05) on IL-5 levels of all treated groups, IL-13 levels in the treated groups had a significant reduction (p<0.001). The OVA groups + MK, OVA + ZIL and OVA + LLLT + MK increased IL-10 levels (p<0.05), with respect to leukotrienes, we noticed a significant decrease (p<0.05) in LTB4 levels OVA + LLLT group than in the OVA group and even greater reduction (p<0.01) in OVA+LLLT+ZIL. In CysLT levels noted a significant decrease (p<0.01) compared to OVA. There was a reduction in the deposition of collagen fibers and mucus in the airways in all treated groups (p<0.001) in the assessment of pulmonary mechanics there was a significant decrease (p<0.001) in all treated groups, at all times evaluated. Taken together, these results indicate that both therapies are effective in reducing allergic inflammation, remodeling and pulmonary elastance. However, the combination therapy seems to have promising role in treating asthma.