Figure 2.

I.V. injection of cellular suspensions derived from idiopathic pulmonary fibrosis (IPF) lung explants induces robust subpleural and interstitial remodeling in nonobese diabetic severe combined immunodeficiency ILR2γ^-/- (NSG) mice. A: Normal and IPF lung explants were mechanically dissociated, and the resulting cellular suspension was stained with various antibodies. Depicted are representative dot plots of cells stained with anti-CD45, EpCAM, CD31, NG2, SSEA4, CD3, CD19, and CD335 antibodies. B and C: Normal and IPF lung explant suspensions were cultured on cell culture–treated plastic dishes in serum-containing medium. Depicted are representative images of fibroblast colonies observed after 1 to 2 weeks of explant cell culture. D and E: 0.5 to 1 × 10⁶ freshly isolated or biobanked lung explant cells alone (D) or mixed 1:1 with isogenic lung fibroblast (1 × 10⁶ total; E) were administered intravenously into NSG mice. Two mice were sacrificed after 31 days (D), and the remainder were sacrificed after 63 days. Lung tissues were isolated and collagen content was determined histologically and biochemically. F and G: The mean hydroxyproline (HYP) content in the superior and middle lobes in unchallenged naive and IPF lung explant (F) or IPF lung explant plus isogenic lung fibroblasts (G) challenged NSG mice at days 31 and 63 (F) or day 63 (G) after cellular injection. H–M: Representative Masson's trichrome staining of naive (H and K), IPF explant cell (I and L), and IPF explant plus isogenic lung fibroblast (J and M) NSG lungs at day 63 after injection. n = 5 unchallenged naive (F and G); n = 2–4 IPF lung explant (F and G); n = 3 IPF lung explant plus isogenic lung fibroblasts (F and G). ^∗P < 0.05, ^∗∗P < 0.01 (unpaired parametric t-test). Original magnification: ×40 (B); ×100 (C); ×50 (H–M). APC, allophycocyanin; FITC, fluorescein isothiocyanate; PE, phosphatidylethanolamine.