High glucose induces vascular endothelial growth factor production in human synovial fibroblasts through reactive oxygen species generation

► High glucose-induced VEGF expression in human synovial fibroblast cells. ► HG activates ROS, PI3K, Akt ,and AP-1 pathways, leading to up-regulation of VEGF expression. ► Involvement of AP-1 in HG-induced VEGF expression.