Figure 4

Influence of microglia on Müller cell expression of inflammatory factors. (A) Semi-quantitative RT-PCR comparing mRNA levels of inflammatory factors in Müller cells cultured alone (white bars), or co-cultured with unactivated (gray bars) or LPS-activated (black bars) microglia. mRNA levels of inflammatory cytokines IL-1β and IL-6, as well as iNOS, were significantly elevated in Müller cell co-cultured with activated microglia, compared with those cultured alone or cultured with unactivated microglia. Expression levels of IFN-γ and TGF-β were similar between the three groups. Representative gel images for genes whose expression were significantly changed following co-culture are shown (right). (B) Protein levels of cytokines in the conditioned media of Müller cells 24 hours following co-culture were measured with ELISA. Inflammatory cytokines, IL-1β and IL-6, were both elevated, while levels of TGF-β were slightly decreased. (C) Nitrite concentrations in conditioned media following co-culture were elevated in Müller cells co-cultured with activated microglia, consistent with the increased expression for iNOS in Müller cells. (* indicates p < 0.05 for comparisons, one-way ANOVA with Tukey-Kramer multiple comparison test, n = 6-8 replicates from two independent experiments).