Transgenic PAI-1 expression induces inflammation in healthy lungs. Representative HE stainings of lung tissue at 24 hours after intranasal inoculation of healthy mice with 5 × 10⁸ PFU Ad.RR5 (A) or Ad.PAI-1 (B). Original magnification, × 200. Insets show representative neutrophil stainings of the same time point; original magnification, × 400. (C) Graphic representation of the degree of lung inflammation, determined according to the scoring system described in “Histologic examination.” (D) MPO levels. Data are means ± SE. n = 8 per group. *P < .01 versus Ad.RR5-treated mice.