Aerobic Exercise Decreases Chronic Allergic Lung Inflammation and Airway Remodeling in Mice

Abstract

Aerobic conditioning improves exercise capacity and decreases symptoms in patients with asthma. However, its benefits in the context of allergic airway inflammation are poorly understood. To evaluate the effects of two intensities of aerobic exercise on airway inflammation and remodeling in a model of chronic allergic lung inflammation. Mice were subjected to chronic ovalbumin (OVA) sensitization and to 4 weeks of low (OVA+Low) or moderate (OVA+Mod) exercise training in a treadmill. Airway inflammation and remodeling and expression of helper T-cell type 1 and 2 cytokines were evaluated. OVA-induced allergic airway inflammation and remodeling were characterized by an increase in collagen (288%), elastic fiber (56%), smooth muscle (380%), and epithelial (402%) contents (P < 0.001) when compared with the control group. OVA+Low and OVA+Mod groups presented a decrease in bronchoalveolar lavage fluid eosinophils (respectively, 84 and 75%; P < 0.01) and airway walls (respectively, 94 and 58%; P < 0.001) when compared with the OVA group. OVA+Low and OVA+Mod groups also presented a reduction in the number of peribronchial inflammatory cells expressing IL-4 (respectively, 85 and 75%; P < 0.01) and IL-5 (respectively, 88 and 89%; P < 0.01) when compared with the OVA group. Aerobic conditioning did not change the expression of either IFN-gamma or IL-2 by inflammatory cells or plasma levels of IgE or IgG1. OVA+Low and OVA+Mod groups presented an increase in the expression of IL-10 (P < 0.001). Low and moderate aerobic conditioning also reduced airway remodeling in OVA-sensitized mice when compared with the OVA group. We concluded that low and moderate aerobic exercise decreases airway inflammation and remodeling in a murine model of asthma.