Effects of butylphthalide on hydrogen peroxide induced retinal pigment epithelial cells injury

Abstract

Objective To investigate the protective effect of butylphenyphthalein (NBP) on RPE apoptosis induced by H2O2. Methods The human RPE cell line (human ARPE-19 cell line) were used as the experimental cells and were divided as control group, model group, NBP group. Complete medium was used in control group. The model group was stimulated with 200 μmol/L H2O2 for 2 h, and the cells were cultured in complete medium. The NBP group was cultured with 200 μmol/L H2O2 and 1 μmol/L NBP for 2 h. After changing the medium, complete medium was combined with 1 μmol/L NBP to continue the culture of the cells. Cell viability were detected by MTT assay while the morphology of RPE were observed by HE staining. Moreover, Hoechst 33258 was used to detect RPE cell apoptosis. Mitochondrial membrane potential (JC-1) staining were performed to monitor changes in cell membrane potential and the characteristic change of apoptosis in RPE cells. Furthermore, 2′,7′-Dichlorofluorescin diacetate (DCFH-DA) staining were used to analyze the effect of NBP treatment on the expression of ROS. The effect of NBP on the expression of Heme oxygenase-1(HO-1) was analyzed by cellular immunofluorescence and western blotting. Results The results of MTT assay showed that the cells were cultured for 24 and 48 hours, cell viability of control group (t=17.710, 13.760; P<0.000 1, <0.000 1) and treatment group (t=4.857, 9.225; P=0.000 7, <0.000 1) were stronger than that of model group, and the difference was statistically significant. HE staining and Hoechst33258 staining showed that compared with the control group, the number of cells in the model group was significantly less, and the cell morphology was incomplete. Compared with the model group, the number of cells in the treatment group was significantly increased, and the cell morphology was better. The results of JC-1 assay showed that the number of apoptotic cells in the model group was significantly higher than that in the control group, and the number of apoptotic cells in the treatment group was significantly lower than that in the model group. DCFH-DA staining showed that the ROS accumulation in the model group was more than that in the control group, and the ROS accumulation in the treatment group was less than that in the model group. Immunostaining observation showed that the HO-1 fluorescence intensity of the cells in the treatment group was significantly higher than that of the control group, and the difference was statistically significant (t=10.270, P=0.000 5). Western blot analysis showed that NBP up-regulated the expression level of HO-1 in a time-dependent manner. The relative expression of HO-1 at 4, 8, and 12 h of NBP showed a clear increase trend compared with 0 h, and the difference was statistically significant (F=164.91, P<0.05). Conclusions Oxidative stress injury can down-regulate the viability of RPE cells and induce apoptosis. NBP can increase the antioxidant capacity of RPE cells, reduce cell damage and inhibit cell apoptosis by up-regulating HO-1 expression. Key words: Retinal pigment epithelium; Apoptosis; Butylphthalide; Oxidative stress