ABSTRACT
Objective To investigate the effects and mechanism of advanced glycosylation end products (AGEs)on endothelial cell senescence and endothelial barrier dysfunction.Methods Human umbilical vein endothelial cells (HUVECs)were isolated and cultured.The cells were randomized into three groups:the control group(normal medium),the bovine serum albumin-treated group(BSA control group)and AEGs group(treated with AEGs-BSA).Senescence of HUVECs were detected by senescence-associated β-galactosidase (SA-beta-Gal)staining.The mRNA and protein expressions of senescence-related genes of p53,p21 and p16 in each group were determined by reverse transcription and real-time PCR(RT-qPCR)and Western blot.Reactive oxygen species(ROS)level was determined by dichlorodihdrofluorescence diacetate (DCFH-DA).The transendothelial electric resistance(TER)were measured by endothelial electric resistance meter.The protein levels of myosin light chain kinase (MLCK),phosphorylated myosin light chain (p-MLC),myosin light chain (MLC)were detected by Western blot.Results Compared with the control group and the BSA control group,the AGEs group showed the significantly increased positive rate of senescence-associated SA-beta-Gal staining (67.30 ± 0.75 ％ vs.7.81 ±0.35 ％ and 7.64 ± 0.91％,respectively,P ＜ 0.01)and the expressions of aging-related genes of p53,p21 and p16 were significantly increased (P ＜ 0.05)There was no significant difference in transendothelial electric resistance(TER)between the control group and theBSAgroup(48.0±6.3 Ω· cm2 vs.42.0±7.8 Ω· cm2,P＞0.05),while TER was lower in the AEGs group than in control group and the BSA group[(27.0±4.2)Ω · cm2 vs.(48.0±6.3)Ω · cm2 and (42.0 ± 7.8) Ω · cm2,P ＜0.01].ROS production had no significant difference between the control group and the BSA group[(38.36 ± 8.55) ％ vs.(41.67 ± 6.93) ％,p ＞ 0.05],while was increased in the AEGs group versus control group and the BSA group[(69.31±8.47)％ vs.(38.36±8.55) ％ and (41.67 ± 6.93) ％,P ＜0.05).The protein expression levels of MLK and p-MLC/MLC were higher in the AGEs group than in the control group and the BSA group(P＜0.05).Conclusions AGEs may lead to endothelial cell senescence and endothelial barrier dysfunction by promoting ROS production and oxidative stress,and by regulating MLCK signaling pathway.