Figure 3

Cholinergic agonist reduces reactive macrophages/microglia in the hippocampus after surgery and LPS. Hippocampi were harvested at 3 and 7 d after surgery/LPS administration and stained with anti-CD68. Epifluorescence shows enhanced immunoreactivity 3 d after surgery (S) and lipopolysaccharide (LPS) exposure. Postoperative infection (S+LPS) further increased the number of CD68+ cells, persisting up to d 7. Administration of a single bolus dose of a selective α7 nAChR agonist (PHA 568487) significantly reduced levels of CD68+ immunoreactivity, returning to baseline at 7 d. Nuclei are counterstained with DAPI. Data are expressed as mean ± SEM and compared by one-way ANOVA and Student-Newman-Keuls method, n = 4 (**P < 0.01 versus C; ^#P < 0.05 versus S; ^##P < 0.01 versus S; ^&&P < 0.01 versus LPS; ^{^^}P < 0.01 versus S+LPS). Scale bar, 30 µm. C, control, S, surgery; PHA, PHA 568487.