FIGURE 6.

Migratory capabilities of BM-derived monocytes are inhibited by nicotine. (A–C) 7-AAD⁺ cells in the total monocyte population (A), CCR2⁺Ly6C^high monocytes (B), and neutrophils (C) were quantified by flow cytometry. (D and E) The number of migratory M-CSF and IFN-γ–induced BM-derived monocytes (D) and neutrophils (E) were assessed by transwell migration assays. (F and G) VLA-4^high expression in total monocytes (F) and CCR2⁺Ly6C^high monocytes (G), and (H and I) LFA-1^high expression in total monocytes (H) and CCR2⁺Ly6C^high monocytes (I) were assessed by flow cytometry. Although nicotine was able to directly inhibit monocyte migratory capabilities in vitro, these data suggest that nicotine does not reduce CNS monocyte or neutrophil numbers by inducing the death of blood monocytes or neutrophils before their infiltration or by reducing their expression of key integrins. Data shown are means ± SEM, whereas an asterisk denotes a significant difference between indicated groups (Mann–Whitney U test, *p < 0.05).