Time course of oxidative stress markers and inflammatory mediators in human conjunctival epithelial cells exposed to diesel exhaust particles

LASAGNI VITAR ROMINA; TAU JULIA; TESONE AGUSTINA; JANEZIC NATASHA; HVOZDA ARANA AILEN; REIDES CLAUDIA; BERRA ALEJANDRO; FERREIRA SANDRA MARIA; LLESUY SUSANA

Seattle

Congreso; The Association for Research in Vision and Ophthalmology Annual Meeting; 2016

The Association for Research in Vision and Ophthalmology

ABSTRACT BODY:Purpose: Ocular discomfort due to urban air pollution has been well documented. Diesel Exhaust Particles (DEP) are the main component of urban particulate matter. The aims of the present study were to evaluate oxidative stressmarkers and inflammatory mediators in human conjunctival epithelial cells exposed to DEP for 1 and 3 h, and to compare these results with the previously reported for a 24 h incubation Methods: Human conjunctival epithelial cells (IOBA-NHC) were incubated at different concentrations of DEP (10, 50and 100 μg/mL.Control: culture medium) for 1, 3 and 24 h. The following parameters were evaluated: reactive oxygen (ROS) and nitrogen species (RNS) production, protein and lipid oxidation, superoxide dismutase (SOD) activity,reduced glutathione (GSH) and IL-6 and IL-8 levels. One-way ANOVA test and Tukey?s test as post hoc test were used for statistical analysisResults: Compared to the control group, the cells exposed to 50 and 100 μg/mL of DEP displayed an increase in ROS (1 h: 64% and 91% 3 h: 31% and 46% 24 h: 22% and 45%, p01) and RNS (1 h: 229% and 500% 3 h: 214% and 457% 24 h: 257% and 514%, p1). SOD activity significantly increased at all time points evaluated (1 h: 36% and 42% 3 h: 84% and 90% 24 h: 85% and 110%, p5). The same experimental groups showed an increase in GSH levels after 3 h of incubation (30% and 41%, p5), but GSH diminished after 24 h (39% and 50% p5). DEP50 and DEP100 groups also presented an increase in lipid oxidation after 1 h of incubation (66% and 79%, p5). Protein oxidation was increased in DEP100 group after 3 and 24 h of incubation (48% and 57%, p5). Higher values of IL-6 release were observed inDEP100 group after the third hour of incubation (54%, p5). Meanwhile, IL-8 levels were significantly decreased after the first hour of incubation (46%, p1). Both cytokines showed the same pattern after 24 h of incubation. There was no significant difference between DEP10 and control groups at all time points evaluated Conclusions: These results suggest that ROS and RNS production seem to be earlier events triggered by the exposure to DEP in human conjunctival epithelial cells, in comparison to the proinflammatory response mediated by IL-6. In these conditions, the antioxidant mechanisms activated were not enough to avoid oxidative damage to macromolecules, developing in cell toxicity