Curcumin activates autophagy and attenuates high glucose-induced apoptosis in HUVECs through the ROS/NF-κB signaling pathway

Curcumin (CUR) is well known for its anti-inflammatory and antioxidant effects. However, the endothelial protective effect of CUR in diabetes and the underlying signaling pathway remains unclear. The goal of the current study was to provide evidence regarding the protective mechanism of CUR against the high glucose (HG)-induced damage to human umbilical vein endothelial cells (HUVECs). HG-induced HUVECs injury model was used to evaluate the protective effect and the underlying mechanism of CUR against endothelial injury. The cell viability was determined by the MTT method. The cell reactive oxygen species (ROS) were determined by using flow cytometry. The protein expression levels of Bcl-2, Bax, LC3-II/I, Beclin-1, p62, cleaved caspase-3, IκBα and NF-κB were measured by the western blotting. Results showed that CUR significantly decreased the cell apoptosis, the ROS generation and the inflammatory cytokine NF-κB activity in the HG-induced HUVECs versus the control, P<0.05. In addition, CUR significantly increased the expressions of LC3-II/I, Beclin-1, IκBα and Bax/Bcl-2 in the HG-induced HUVECs versus the control, P<0.05. Furthermore, the addition of autophagy inhibitor 3-MA impaired the autophagy, exacerbated the apoptotic death and increased the ROS and NF-κB levels in HUVECs under the high glucose condition, P<0.05. In brief, autophagy served a protective role in the HG-induced apoptosis in HUVECs and CUR alleviated apoptosis by promoting autophagy and inhibiting the ROS/NF-κB signaling pathway.