Empagliflozin alleviates lipopolysaccharide-induced endothelial cell injury by activating Nrf2 signaling

  AIM  To observe the protective effect and mechanism of empagliflozin (Em) against lipopolysaccharide (LPS) induced injury of human umbilical vein endothelial cells (HUVEC).

  METHODS  HUVEC were randomly divided into 4 groups: control group, LPS (1 μg/ml) group, LPS+Em (1 μmol/L) group and LPS+Em+Nrf2 siRNA group. HUVEC were pretreated with Em and Nrf2 siRNA for 12 h and then were treated with LPS for 24 h. The changes of cell morphology were observed under inverted microscope and the viability of HUVEC was detected by CCK-8 method. Nuclear factor erythroid2-related factor 2(Nrf2), NADPH-Oxidase 2(NOX2), NADPH-Oxidase 4(NOX4), Bcl-2 associated X protein(BAX) and B-cell lymphoma-2(Bcl-2) were detected by Western blotting DCFH-DA staining was used to observe the changes in the content of ROS, TUNEL staining was used to observe the degree of apoptosis and immunofluorescence staining was used to detect the expression of Nrf2 in each group.

  RESULTS  Compared with those in control group, the cell viability was decreased (P<0.01), the expression of Bax was increased (P<0.05), the expression of Bcl2 was decreased (P<0.05), the apoptosis rate was increased (P<0.05), the contents of NOX2, NOX4 and ROS were increased (P<0.05) and the expression of Nrf2 was decreased (P<0.05) in LPS group. Em treatment significantly increased the cell viability (P<0.01), decreased Bax expression and apoptosis rate (P<0.05), increased Bcl2 expression (P<0.05), decreased NOX2 and NOX4 expression and ROS content (P<0.05), and increased Nrf2 expression (P<0.05). However, Nrf2 siRNA treatment significantly blocked the protective effect of Em on HUVEC and the regulation of Nrf2 signaling (P<0.05).

  CONCLUSION  Empagliflozin ameliorates lipopolysaccharide induced HUVEC injury and the mechanism is related to activating Nrf2 signaling and reducing oxidative stress.