Effect of peroxisome proliferator-activated receptor-γ on endothelial cells oxidative stress induced by Porphyromonas gingivalis / 北京大学学报(医学版)

ABSTRACT

Objective:To detect the degree of oxidative stress in the process when Porphyromonas gin-givalis ( P. gingivalis) stimulates human vascular endothelium, And to investigate the effect of peroxi-some proliferator-activated receptor(PPAR)γ on oxidative stress during this process. Methods:Human vascular endothelial cells ( HVECs) line EA. hy926 ( American Type Culture Collection ,United States) was cultured in high glucose Dulbecco' s modified eagle medium ( DMEM) . Four groups were designedcontrol group, P. gingivalis infected group, PPARγactivated group and PPARγblocked group. In con-trol group HVECs were cultured with only DMEM. In P. gingivalis infected group, HVECs were time-dependently stimulated by P. gingivalis W83 from 0 to 12 h. In PPARγ activated group or PPARγblocked group, PPARγ was pre-activated or blocked by a representative PPARγ agonist(15d-PGJ2 10μmol/L) or antagonist ( GW966210μmol/L) 30 minutes before the cells were stimulated by P. gingiva-lis. At 0, 0. 5, 1, 1. 5, 2, 4, 8, and 12 h, the culture medium was collected individually and centri-fuged, and the supernatant was stored for assay. Glutathione peroxidase (GSH-PX) and malondialdehyde( MDA) were analysed by enzyme-linked immunosorbent assay. Cellular reactive oxygen species ( ROS) were detected through 2',7'-dichlorofluorescin diacetate (DCFA-DA) fluorescent probe at various time points of the different groups. Results:In P. gingivalis infected group, the levels of GSH-PX [(5. 56 ± 0. 97) μmol/L] and MDA [(0. 84 ± 0. 18) nmol/L] were significantly higher than those in control group [GSH-PX(4. 71 ± 0. 64) μmol/L, MDA (0. 59 ± 0. 18) nmol/L)]. The levels of GSH-PX and MDA in PPARγactivated group [GSH-PX (5. 38 ± 0. 84) μmol/L, MDA (0. 84 ± 0. 22) nmol/L] and in PPARγblocked group [GSH-PX (5. 37 ± 0. 76) μmol/L, MDA (0. 85 ± 0. 14) nmol/L] were signi-ficantly higher than those in control group (P <0. 05). In the PPARγ activated group, the levels of GSH-PX at 0 . 5 and 8 h were significantly higher than those from 1 . 5 h to 4 h ( P<0 . 05 ) , while no difference was observed on the MDA levels at different time points. There was no significant difference at various time points for the levels of GSH-PX and MDA in PPARγ blocked group. The level of cellular ROS detected by DCFH-DA in P. gingivalis infected group was significantly higher than that in control group (10 108. 65 ± 1 805. 18 vs. 6 049. 06 ± 1 199. 19,P<0. 05). No difference was observed be-tween PPARγ activated group (7 120. 94 ± 1 447. 30) or PPARγblocked group (6 727. 35 ± 1 483. 68) and control group. Conclusion:Oxidative stress happens when P. gingivalis stimulates human vascular endothelium. PPARγ may involve in modulating oxidative stress during this process.