Abstract
In recent years an increasing number of studies have shown that low level laser (LLL) therapy is able to reduce lung inflammation. More recently, it was first demonstrated that LLL has direct anti-inflammatory effects in the airways of the asthma patient, evidenced by decreased number of eosinophils in the sputum. In this context, important questions and hypotheses have been raised about the mechanisms involved in this effect. Accordingly, despite the increasing number of studies in experimental animal models of pulmonary inflammation, no studies have evaluated so far the effects of LLL on leukotriene secretion. Therefore, the present study aims to assess whether the anti-inflammatory effects of LLL in asthma is somehow mediated changes in leukotriene synthesis or receptor expression. To achieve that, BALB/c male mice were divided into 4 experimental groups: (control, n = 20; LBP, n = 20; asthma, n = 20; and asthma + LLL, n = 20). Allergic lung inflammation is induced by subcutaneous injection of ovoalbumin (OVA) on days 0 and 14. From day 21, the animals are subjected to intranasal OVA challenge, three times a week for 5 weeks. Laser therapy is applied before challenge with OVA (2 times/day). Twenty-four hours after the last OVA challenge and laser irradiation, animals will be anesthetized, tracheotomized, cannulated and bronchoalveolar lavage collected for analysis of total and differential counting of cells and the expression of IL-4, IL-5, IL-10 and IL-13 by inflammatory cells. It will also be evaluated deposition of collagen and elastic fibers (in the airways and pulmonary vessels) as well as the thickening of the bronchial smooth muscle and vascular as well as bronchial epithelial layer. (AU)
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