Figure 3.

Loss of MMP-8 affects MMTV-PyMT neutrophil, but not macrophage, infiltration and expression of proinflammatory mediators. (A) Number of macrophages/mm² and neutrophils/mm² in early- and late-stage tumors as determined by staining for F4/80 and Ly6B.2, respectively. The number of mice used for analyses of macrophage and neutrophil infiltration respectively were at 6 weeks: Mmp8 wild-type (WT, n = 5, 5), heterozygote (HET, n = 4, 3) and null (KO, n = 2, 3); 8 weeks: Mmp8 wild-type (WT, n = 4, 5), heterozygote (HET, n = 6, 5), null (KO, n = 4, 5) and at 10 weeks: Mmp8 wild-type (WT, n = 5, 5), heterozygote (HET, n = 5, 5) and null (KO, n = 4, 4).^* P <0.05, ^** P <0.01. One representative image of macrophage and neutrophil staining is shown for each genotype at 10 weeks of age. (B) Relative RNA expression of macrophage marker CD68, IL-6 and CXCL5/LIX, normalized to 18S rRNA, throughout disease progression (6 to 14 weeks of age). IL, interleukin; MMP, matrix metalloproteinase; MMTV, mouse mammary tumor virus; PyMT, Polyoma virus middle T-antigen.