Figure 6. H1N1-infected Mmp-9^–/– mice had lower lung levels of some pro- and antiinflammatory mediators than H1N1-infected WT mice.

WT and Mmp-9^–/– mice (4–10 mice/group) were infected with an LD₂₀ inoculum of H1N1 by the intranasal route. Uninfected control (UC) mice served as controls. At postinfection intervals, lungs were removed, and lung levels of Cxcl-2 (A), Cxcl-6 (B), Ccl-2 (C) Ccl-3 (D), Ccl-5 (E), Il-6 (F), G-csf (G), Tnf-α (H), and Tgf-β (I) were measured using ELISAs. Lung levels of mediators were normalized to lung total protein levels. The box-and-whisker plots show medians and 25th and 75th percentiles, and the whiskers showing 10th and 90th percentiles. Data were analyzed with 1-way ANOVAs followed by pair-wise testing with Mann-Whitney U tests. *P < 0.05 versus the group indicated.