ATP Is Required and Advances Cytokine-Induced Gap Junction Formation in Microglia In Vitro

Figure 4

TNF-α/IFN-γ induces membrane permeabilization in EOC20 cells. (a) Time-lapse measurements of ethidium (Etd) uptake in EOC20 cells under control conditions (white squares), or after treatment with TNF-α/IFN-γ (black diamonds) or IL-6/TNF-α/IFN-γ (gray triangles) for 9 h. Each value represents the mean ± SEM of 30 cells. After 10 min of basal uptake, 200 μM La³⁺ was applied to the bath. (b)–(d) Representative fluorescence micrographs of Etd uptake after 10 min of Etd uptake under indicated treatments, previous to La³⁺ application. Scale bar: 100 μm. (e) Graph showing the acute effect of 200 μM La³⁺, 10 μM carbenoxolone (Cbx), or pretreatment with 50 ng/mL of interleukin-6 (IL-6) Etd uptake rate expressed as percentage of control conditions (dashed line) in EOC20 cells treated with TNF-α/IFN-γ for 9 h. Each bar corresponds to the mean ± SEM, 𝑛=5. ^∗𝑃<0.05 versus control condition.