Aerobic exercise reduces lung inflammation and fibrosis mediated by serotoninergic/Akt signaling in a model of pulmonary fibrosis

Abstract

Idiopathic pulmonary fibrosis (IPF) is characterized by decline of lung function, inflammation and fibrosis, with serotonin (5-HT) and Akt signaling presenting a key role. Aerobic training (AT) reduces lung injury in models of pulmonary diseases. However, the mechanisms underlying the effects of AT in a model of bleomycin-induced lung fibrosis is unknown. Thus, this study investigated the effects of AT in a model of bleomycin-induced pulmonary fibrosis, as well as the participation of 5HT/Akt signaling. Seventy-two C57Bl/6 male mice were distributed in Control (Co), Exercise (Ex), Fibrosis (Fi) and Fibrosis+Exercise (Fi+Ex) groups. Bleomycin (1.5UI/Kg) was administered on day 1 and treadmill AT began on day 14 during 4 weeks. Total and differential cells count in bronchoalveolar lavage (BAL), IL-1beta, IL-6, CXCL1/KC, IL-10, TNF-alpha and TGF-beta levels in BAL fluid, collagen content in the lung parenchyma, 5-HT levels in BAL fluid and in serum, and the expression of 5-HT2b receptor and Akt were evaluated. AT reduced bleomycin-induced number of total cells (p