Figure 2

PHA 568487 effects on CD11b activation following surgery and LPS. Hippocampi were harvested at 3 and 7 d after surgery/LPS administration and stained with anti-CD11b. Photomicrographs show CA1 of control animals (C), surgery (S), lipopolysaccharide (LPS), surgery with postoperative LPS (S+LPS) and in combination with a bolus dose of a selective α7 nAChR agonist (S+LPS+PHA) at 3 d. Higher CD11b immunoreactivity was observed after surgery and LPS exposure at both 3 and 7 d (P < 0.01, P < 0.05 respectively). Significant hypertrophy of the cell bodies and loss of pseudopodia occurred in LPS-treated mice after orthopedic surgery; this was attenuated by administration of PHA 568487 2 h after LPS onset (P < 0.01 versus S+LPS). Reactive microglia/monocytes were present up to d 7 in the S+LPS group and returned to baseline in the other treatment groups. 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 < 0.05 versus LPS; ^{^}P < 0.05 versus S+LPS; ^{^^}P> 0.01 versus S+LPS). Scale bar, 50 µm. C, control; S, surgery; PHA, PHA 568487.