Toxicity of cooking oil fume derived particulate matter: Vitamin D3 protects tubule formation activation in human umbilical vein endothelial cells.

Cooking oil fumes-derived PM2.5 (COFs-derived PM2.5) is the main source of indoor pollution. Exposure to COFs-derived PM2.5 can cause oxidative stress and affect angiogenesis. Here we investigated the roles of vitamin D3 (VD3) in protecting tubule formation injury induced by COFs-derived PM2.5, and the roles of ROS/NLRP3/VEGF signaling pathway in the effects. Human umbilical vein endothelial cells (HUVECs) were exposed to 0 (1‰ DMSO), 1000 nmol/l VD3, 100 μg/ml PM2.5, and 1000 nmol/l VD3 + 100 μg/ml PM2.5, respectively. Cell viability and tube formation, as well as protein and mRNA levels were measured. The results showed that exposure of COFs-derived PM2.5 dose-and time-dependently reduced the viability of HUVECs, increased the levels of mitochondrial and intracellular ROS, and changed the mitochondrial membrane potential level. While co-incubation with VD3 rescued these adverse effects. Both Western blot and real-time PCR (RT-PCR) showed that the expressions of NLRP3, caspase-1, Interleukin (IL)-1β, and IL-18 in COFs-derived PM2.5 exposure group increased significantly, which could be effectively decreased by co-incubation with VD3. COFs-derived PM2.5 exposure could also reduce the expression of VEGF, while co-incubating HUVECs with VD3 evidently up-regulated the protein level of VEGF in HUVECs. In addition, COFs-derived PM2.5 could also inhibit the tube formation of HUVECs in vitro, which could be effectively rescued by the co-incubation of VD3. Our study proved that COFs-derived PM2.5 could damage the tubule formation of HUVECs in vitro, which could be effectively rescue by co-incubation with VD3, in which processes the ROS/NLRP3/VEGF signaling pathway played a crucial role. It provides a new theoretical basis for further study on the toxicity of PM2.5 to umbilical cord blood vessels.