Müller glia produce reactive nitrogen species following S. aureus challenge. MIO-M1 cells were challenged with S. aureus (SA) for the indicated time points. The level of NO in the culture media was determined by measuring the concentration of one of its stable metabolites, nitrite, using the Griess reagent (A). RNA extraction and RT-PCR for inducible nitric oxide synthase (iNOS) expression was performed on the cells. (B). The data represent mean ± SD of triplicates from three independent experiments. Statistical analysis was performed using one-way ANOVA, for comparisons of control versus infected cells over time. (*P < 0.05; ns, not significant).