Role of vascular peroxidase 1 in senescence of endothelial cells in diabetes rats.

Background: Reactive oxygen species (ROS) is thought as a major reason of vascular injury in diabetes. Vascular peroxidase 1 (VPO1) is a newly found peroxidase playing an important role in inducing oxidative stress. In the present experiment, we tested the role of VPO1 in senescence of endothelial cells in streptozotocin (STZ)-induced diabetic rats and cultured endothelial cells.

Methods: Blood samples were collected from carotid arteries. Vasodilator responses to acetylcholine (Ach) in the isolated aortic rings were measured, serum concentration of glucose, tumor necrosis factor-α (TNF-α) and monocyte chemoattractant protein-1 (MCP-1) and the expression of VPO1 in the aorta were determined. Endothelial cells were treated with high glucose or H2O2, the concentrations of MCP-1, TNF-α and hypochlorous acid (HOCl) and the expression of VPO1 were determined. shRNA of VPO1 was used for mechanism research in cultured cells.

Results: Vasodilator responses to Ach were impaired markedly and the serum concentrations of glucose, TNF-α and MCP-1 were significantly increased in diabetic rats. The expression of VPO1 in the aorta was upregulated in diabetic rats. High glucose treatment significantly decreased cell viability and elevated the levels of MCP-1, TNF-α and HOCl and upregulated the expression of VPO1. H2O2 treatment significantly induced cellular senescence, inhibited eNOS expression and NO production. The effects of high glucose and H2O2 were attenuated by shRNA interference of VPO1.

Conclusions: VPO1 plays an important role in senescence of endothelial cells and endothelial dysfunction by induction of oxidative stress and inflammatory reaction in type 2 diabetic rats.