Figure 5

Müller cells, following co-culture with microglia, can induce reciprocal activation of retinal microglia. Following microglial co-culture, fresh media were added to Müller cells from each co-culture condition, left to condition for 24 hours, and then collected and tested for the ability to induce microglial activation. These conditioned media were added to fresh, unactivated cultured microglia for 24 hours. The ability of conditioned media to induce reciprocal microglial activation was assessed by measuring microglial mRNA expression of proinflammatory factors and microglial proliferation. (A) Conditioned media from Müller cells co-cultured with activated microglia were able to induce the highest levels of IL-1β, IL-6, iNOS, and CCL2 expression in microglia. Microglial expression levels of TNF-α and IFN-γ remained unchanged between three groups. Representative gel images for genes whose expression were significantly changed following co-culture are shown (right). (B) Microglia proliferation, as measured by BrdU incorporation, was significantly elevated in the conditioned media from Müller cells exposed to activated microglia, relative to other conditioned media. (* indicates p < 0.05 for comparisons, one-way ANOVA with Tukey-Kramer multiple comparison test, n = 6-8 replicates from two independent experiments).