Vaspin protects against lipopolysaccharide-induced acute respiratory distress syndrome in mice by inhibiting inflammation and protecting vascular endothelium via PI3K/Akt signal pathway

Abstract

To investigate the effects of Vaspin on lipopolysaccharide (LPS)-induced acute respiratory distress syndrome (ARDS) in mice and explore the possible mechanism. Forty male C57B/L6 mice were randomized equally into control group, LPS group, Vaspin group and wortmannin group with corresponding treatments. The pathological changes of the lung tissues were evaluated by HE staining, and the severity of pulmonary edema was measured according to the wet/dry ratio (W/D) of the lung tissue. The lung permeability was evaluated by detecting total protein concentrations in the bronchoalveolar lavage fluid (BALF) using bicinchoninic acid (BCA) assay. Myeloperoxidase (MPO) activity in the lung tissue was detected using a MPO assay kit, and the levels of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) in the lungs were measured using ELISA. Immunohistochemical staining was performed to detect the expression of vascular cell adhesion molecule-1 (VCAM-1) and Western blotting was used to detect the protein expressions of cleaved caspase-3 and p-Akt in the lung tissues. Compared with the control group, the mice in LPS group displayed typical ARDS pathological changes in the lungs with significantly increased W/D, total protein concentrations in BALF, lung MPO activity, levels of IL-1β and TNF-α, and pulmonary expressions of VCAM-1 and cleaved caspase-3 (P<0.05) but decreased expression of p-Akt (P<0.05). These changes induced by LPS were significantly alleviated by the administration of Vaspin (P<0.05). The protective effects of Vaspin against ARDS were obviously attenuated by the PI3K inhibitor wortmannin (P<0.05). Vaspin protects against LPS-induced ARDS in mice possibly by inhibiting inflammation and protecting vascular endothelium through upregulation of the PI3K/Akt signal pathway.