Immunocytochemical analysis of microglia. Mice were treated as described above. (A) Levels of immunoreactive density of Iba1, a marker of microglia, in cortex and hippocampal dentate gyrus were quantified using BioQuant image analysis software and presented as mean ± SEM in pixel/mm2. Ethanol alone, poly I:C alone and ethanol-poly I:C treated groups all show increased Iba1 + IR in both brain regions. (B) Representative images of Iba1 + IR cells in cortex and dentate gyrus from control and ethanol-poly I:C-treated groups. In water control group, microglia showed a resting morphological shape. In either ethanol or poly I:C alone-treated groups, some of the microglia are enlarged (images not shown). Iba1 + IR cells in EtOH-poly I:C-treated mouse brains have increased cell size, irregular shape, and intensified Iba1 staining consistent with morphological changes in activated microglia. Scale bar, 200 μm.