IGFBP2 downregulation in adenoviral TGF-β1-induced pulmonary fibrosis in aged mice
(A) Sirius red (top)- or Mason’s trichrome (bottom)-stained lung sections of aged (78–82 weeks old) WT mice 28 days after intratracheal administration of Ad-null or Ad-TGF-β1 virus (5 × 108 PFU). Scale bars, 50 μm (n = 6 Ad-null; n = 6 Ad-TGF-β1).
(B) Hydroxyproline content (μg per mg of lung) in the lungs of 18-month-old mice 28 days after intratracheal administration of Ad-null or Ad-TGF-β1 virus (n = 6 Ad-null; n = 6 Ad-TGF-β1).
(C) Representative double-color immunohistochemistry lung images of aged WT mice challenged with Ad-Null or Ad-TGF-β1 virus. Green color indicates SPC expression; brown color indicates IGFBP2 or P21 or phospho-H2AX expression. Black arrowheads indicate the double-positive AEC2 cells. Scale bars, 10 μm (n = 6 Ad-null; n = 6 Ad-TGF-β1).
(D) Quantification of percentages of double-positive cells for IGFBP2, P21, and phospho-H2AX expression in SPC + cells, respectively. Data are mean ± SEM ∗∗p < 0.01, and ∗∗∗p < 0.001, Student’s unpaired two-tailed t test.