Omentin-1 protects against bleomycin-induced acute lung injury.

Acute lung injury (ALI) is characterized by inflammatory cell infiltration, macrophage activation, and excessive pro-inflammatory cytokine production. Bleomycin (BLM) is widely used to induce acute lung injury (ALI) and fibrosis in murine models. Intratracheally administration of BLM leads to the early stage of inflammatory response and the late stage of collagen deposition. Omentin-1 exerts an anti-inflammatory role in reducing tumor necrosis factor α (TNF-α)-induced cyclooxygenase-2 expression in endothelial cells and attenuating lipopolysaccharide (LPS)-induced ALI. However, the role of omentin-1 in BLM-induced ALI remains unclear. The aim of this study is to examine the effects of omentin-1 on BLM-induced ALI. We found that omentin-1 was decreased in lungs of BLM-induced ALI mice. Omentin-1 overexpression mediated by adenovirus alleviated lung injury and maintained the integrity of the alveolar septa. Omentin-1 overexpression also remarkably decreased the aggregation of neutrophil and macrophages activation, the expression of monocyte chemotactic protein 1 (MCP-1), and down-regulated expression of interleukin 1β (IL-1β) in lungs of BLM-induced ALI mice. Furthermore, we observed that omentin-1 reduced oxidative stress and suppressed the activation of NF-κB pathway in BLM-induced ALI and LPS-induced macrophages activation. Together, our findings indicated that omentin-1 protected mice from BLM-induced ALI may through reducing inflammatory cells recruitment and macrophages activation via alleviation of oxidative stress and NF-κB pathway. Thus, therapeutic strategies aiming to restore omentin-1 levels may be valuable for the prevention of BLM-induced ALI.