Paeoniflorin protects HUVECs from AGE-BSA-induced injury via an autophagic pathway by acting on the RAGE

The aim of our study was to investigate the protective effects of Paeoniflorin (PF) against injury induced by AGE-modified bovine serum albumin (AGE-BSA) in human umbilical vein endothelial cells (HUVECs), and to examine the underlying mechanisms of these effects. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was used to determine cell viability. Protein expression levels were determined by western blotting. For function-blocking experiments, we used small interfering RNA molecules (siRNA) for function-blocking experiments. At 6 h, we found that 100 μg/mL AGE-BSA reduced the viability of HUVECs. However, pretreatment with PF restored cell viability in a dose-dependent manner. AGE-BSA increased the levels of microtubule-associated protein light chain 3-II (LC3-II) and the receptor for advanced glycation end products (RAGE). Expression of p62 protein was also increased, but not at a statistically significant level. Pretreatment with PF further increased levels of LC3-II and RAGE, but reduced the expression of p62. In cells transfected with Atg5 and RAGE siRNA, cell viability and expression of LC3-II decreased in both the AGE-BSA and PF + AGE-BSA treatments. PF can protect HUVECs from AGE-BSA-induced injury by upregulating autophagy and promoting the completion of autophagy flux. RAGE plays an important role in this autophagic protection effect.