Figure 5. Effect of AG490 on cortical astrocyte cell function and STAT-3 phosphorylation.

Cells from wild-type black C6 mice were pretreated for 2 hr with 25 µM AG490 followed by 1 hr exposure to 10 ng/ml interleukin 6 (IL-6) or 100 µm H₂O₂. (A) AG490 (AG) suppressed both basal and IL-6-stimulated STAT-3 phosphorylation. 25 µg of total protein was applied to each lane. (B) Prolonged AG490 exposure suppressed cell proliferation and reduced cell number after 1 day in vitro. Cell number was assessed by relative fluorescence of propidium iodide in the presence of 160 µM digitonin (C, D) Measurement of mitochondrial membrane potential using JC-1 and reduced GSH using MCB. Values represent means of 4 determinations ± SEM. These studies were repeated twice with similar results. * p<0.05 comparing AG490-treated with untreated cells. ∧ p<0.05 comparing H₂O₂- treated with corresponding control cells by 2-way ANOVA with Bonferroni post-hoc test.