Figure 2.
Deficient neutrophil extravasation in FasL-deficient mice. (A) Macrophage and neutrophil numbers in BAL fluid from mice instilled with PBS or silica intratracheally. Silica exposed BALB.gld mice (black bars) showed a 5.8-fold reduction in neutrophil number (P < 0.01, n = 4), and a 4.0-fold increase in macrophage number (P < 0.01, n = 4), compared with BALB.wt mice (white bars). SIL, silica. (B) MPO activity. Mean MPO activity of both BAL cells and lung parenchyma of wt and gld mice instilled with PBS alone (n = 4 pools of 3 mice each) was taken as 100% of control value. Left: MPO activity of BAL cells from mice instilled with silica. Cells from BALB.gld (▪) mice had much less MPO activity than cells from BALB.wt (•) mice (P < 0.05). Right: after BAL removal, lung parenchyma from BALB.wt (•), but not from BALB.gld (▪) mice, had significant MPO activity, compared with PBS-instilled controls (P < 0.01, and NS, respectively). (C) Cytospin aspect of BAL cells. BAL cells were cytocentrifuged and stained with May-Grunwald. Top: BAL cells from BALB.wt mice after saline instillation were unstimulated alveolar macrophages. Middle: BAL cells from BALB.wt mice after silica instillation were mainly neutrophils, a minority were large macrophages. Bottom: BAL cells from BALB.gld mice after silica instillation were mainly large macrophages, a minority were neutrophils. Original magnification: ×630.