Protective effect of paeoniflorin against oxidative stress in human retinal pigment epithelium in vitro

PURPOSE: This study was conducted to determine whether paeoniflorin (PF) could prevent H(2)O(2)-induced oxidative stress in ARPE-19 cells and to elucidate the molecular pathways involved in this protection. METHODS: Cultured ARPE-19 cells were subjected to oxidative stress with H(2)O(2) in the presence and absence of PF. The preventive effective of PF on reactive oxygen species (ROS) production and retinal pigment epithelium (RPE) cell death induced by H(2)O(2) was determined by 2’,7’- dichlorodihydrofluorescein diacetate (H(2)DCFDA) fluorescence and 3-(4, 5-dimethylthiazol-2-yl)-2, 5 diphenyl tetrazolium bromide (MTT) assay. The ability of PF to protect RPE cells against ROS-mediated apoptosis was assessed by caspase-3 activity and 4', 6-diamidino-2-phenylindole (DAPI) staining. Furthermore, the protective effect of PF via the mitogen-activated protein kinase (MAPK) pathway was determined by western blot analysis. RESULTS: PF protected ARPE-19 cells from H(2)O(2)-induced cell death with low toxicity. H(2)O(2)-induced oxidative stress increased ROS production and caspase-3 activity, which was significantly inhibited by PF in a dose-dependent manner. Pretreatment with PF attenuated H(2)O(2)-induced p38MAPK and extracellular signal regulated kinase (ERK) phosphorylation in human RPE cells, which contributed to cell viability in ARPE-19 cells. CONCLUSIONS: This is the first report to show that PF can protect ARPE-19 cells from the cellular apoptosis induced by oxidative stress. The results of this study open new avenues for the use of PF in treatment of ocular diseases, such as age-related macular degeneration (AMD), where oxidative stress plays a major role in disease pathogenesis.