Aerobic Exercise Attenuated Bleomycin-Induced Lung Fibrosis in Th2-Dominant Mice.

INTRODUCTION: The aim of this study was to investigate the effect of aerobic exercise (AE) in reducing bleomycin-induced fibrosis in mice of a Th2-dominant immune background (BALB/c). METHODS: BALB/c mice were distributed into: sedentary, control (CON), Exercise-only (EX), sedentary, bleomycin-treated (BLEO) and bleomycin-treated+exercised (BLEO+EX); (n = 8/group). Following treadmill adaptation, 15 days following a single, oro-tracheal administration of bleomycin (1.5U/kg), AE was performed 5 days/week, 60min/day for 4 weeks at moderate intensity (60% of maximum velocity reached during a physical test) and assessed for pulmonary inflammation and remodeling, and cytokine levels in bronchoalveolar lavage (BAL). RESULTS: At 45 days post injury, compared to BLEO, BLEO+EX demonstrated reduced collagen deposition in the airways (p<0.001) and also in the lung parenchyma (p<0.001). In BAL, a decreased number of total leukocytes (p<0.01), eosinophils (p<0.001), lymphocytes (p<0.01), macrophages (p<0.01), and neutrophils (p<0.01), as well as reduced pro-inflammatory cytokines (CXCL-1; p<0.01), (IL-1ß; p<0.001), (IL-5; p<0.01), (IL-6; p<0.001), (IL-13; p<0.01) and pro-fibrotic growth factor IGF-1 (p<0.001) were observed. Anti-inflammatory cytokine IL-10 was increased (p<0.001). CONCLUSION: AE attenuated bleomycin-induced collagen deposition, inflammation and cytokines accumulation in the lungs of mice with a predominately Th2-background suggesting that therapeutic AE (15-44 days post injury) attenuates the pro-inflammatory, Th2 immune response and fibrosis in the bleomycin model.

Dendritic Cells Are Involved in the Effects of Exercise in a Model of Asthma.

INTRODUCTION: This study investigated the effects of aerobic exercise (AE) on both the maturation of dendritic cells (DC) and the activation of lymphocytes in a mouse model of chronic allergic airway inflammation. METHODS: C57BL/6 mice distributed into control, exercise, ovalbumin (OVA), and OVA + exercise groups were submitted to OVA sensitization and challenge. Treadmill training was performed for 4 wk, and mice were assessed for classical features of chronic allergic airway inflammation as well as dendritic cell activation and T-lymphocyte response. RESULTS: AE reduced OVA-induced eosinophilic inflammation as observed in bronchoalveolar lavage fluid (P < 0.001), airway walls (P < 0001), and also reduced collagen deposition (P < 0.001). AE also reduced bronchoalveolar lavage fluid cytokines (interleukin [IL]-4, P < 0.001; IL-5, P < 0.01; IL-6, P < 0.001; IL-13, P < 0.01; and tumor necrosis factor α, P < 0.01). Cells derived from mediastinal lymphnodes of AE animals that were restimulated with OVA produced less IL-4 (P < 0.01), IL-5 (P < 0.01), and IL-13 (P < 0.001). In addition, AE reduced both DC activation, as demonstrated by reduced release of IL-6 (P < 0.001), CXCL1/KC (P < 0.01), IL-12p70 (P < 0.01), and tumor necrosis factor α (P < 0.05) and DC maturation, as demonstrated by lower MCH-II expression (P < 0.001). CONCLUSION: AE attenuated dendritic cell and lymphocyte activation and maturation, which contributed to reduced airway inflammation and remodeling in the OVA model of chronic allergic airway inflammation.