Double staining of IgG extravasation and microglia. (A) In addition to microglia, lectin staining also reveals blood vessels. Cholesterol-enriched diet markedly increased the numbers of microglia (green, arrow heads) and IgG extravasation (red). These effects were blocked by caffeine at the dose of 3 mg/day for 12 weeks. Representative images taken from 2 rabbits in each group with 6 sections from each animal are shown. Bar = 50 μm. (B) In a magnified view of the white boxes as shown in panel A, increased microglia (arrow heads) are co-distributed with perivascular immunopositive IgG staining (arrows) in olfactory bulb from cholesterol-fed rabbits. Bar = 20 μm.