Figure 1
Effects of perfluorooctanoic acid (PFOA) on human corneal cells. (a) PFOA showed minimal cytotoxicity against human corneal epithelial cells (HCEpiC) treated with different concentrations of PFOA for 72 h. Cell viability was evaluated using the MTT assay. (b) PFOA induced the production of reactive oxygen species (ROS) in HCEpiC treated with different concentrations of PFOA for 6 h. Levels of ROS were determined using 2,7-dichlorofluorescin diacetate (DCFH-DA). Experimental groups were compared using ANOVA (P < 0.0001), and Dunnett’s multiple comparisons tests were used for paired comparisons between phosphate-buffered saline (PBS; control) and 0.5% (v/v) DMSO, 400 ppm PFOA, 200 ppm PFOA or 100 ppm PFOA-treated HCEpiC. P values below 0.05 were considered to indicate statistical significance. (c) PFOA altered tight junctions in HCEpiC. Relative transepithelial electrical resistance (TEER) was measured in HCEpiC incubated with PBS (control), 0.5% DMSO, 400 ppm PFOA, or 200 ppm PFOA for 24 h. Experimental groups were compared using ANOVA (P < 0.0001), and Dunnett’s multiple comparisons tests were used for paired comparisons between control and 0.5% DMSO, 400 ppm PFOA or 200 ppm PFOA-treated HCEpiC. P values below 0.05 were considered to indicate statistical significance. (d) PFOA treatment decreased the expression level of claudin-1. Cells were treated with different concentrations of PFOA for 24 h, and the level of claudin-1 was determined by western blotting. β-actin was used as an endogenous reference protein. The expression levels of claudin-1 were normalized against β-actin and the relative expression levels compared with the control were noted above each lane. (e) Levels of IL-6 and IL-8 in HCEpiC. Cells were seeded on transwell inserts with a 0.4-µm pore size incubated with PBS (control) or 400 ppm PFOA for 16 h, and the levels of IL-6 and IL-8 in apical and basolateral compartments were determined using enzyme-linked immunosorbent assays. Unpaired t-test was used to determine significant differences between control and PFOA treated groups. P values below 0.05 were considered to indicate statistical significance. Asterisks denote statistical significance.
