Effects of angiopoietin 4 on lipopolysaccharide-induced injury of human umbilical vein endothelial cells

AIM: To observe the effects of angiopoietin 4( Ang-4) on lipopolysaccharide( LPS)-induced injury of human umbilical vein endothelial cells( HUVECs). METHODS: The EnVision immunohistochemical method was used to identify the HUVECs. After pre-treated with different doses of Ang-4 for 0. 5 h,HUVECs was exposed to LPS at concentration of 10 mg / L for 24 h. The cell viability was evaluated by MTT assay. The content of tumor necrosis factor-alpha( TNF-α) in the supernatant and the concentrations of intracellular and supernatant von Willebrand factor( vWF) were detected by ELISA. The mRNA levels of Toll-like receptor 4( TLR4),NF-κB p65 and TNF-α were determined by realtime PCR. RESULTS: Factor Ⅷ in the cytoplasm was positive in the HUVECs. Compared with normal group,LPS reduced the cell viability( P 0. 01),and significantly increased the secretion of TNF-α and vWF( P 0. 01). The mRNA expression of TLR4,NF-κB p65 and TNF-α also increased( P 0. 01). Ang-4 at concentration of 100 μg / L enhanced the cell viability( P 0. 01),reduced the content of vWF and TNF-α,and inhibited the LPS-induced increases in the mRNA levels of TLR4,NF-κB p65 and TNF-α( P 0. 01). CONCLUSION: Ang-4 antagonizes LPS-induced damage in HUVECs by inhibiting TLR4-NF-κB p65-TNF-α signaling pathways.