a, Effects of Mmp13 knockdown in gel-coated D1 mouse MSCs (μMSCs) on hydroxyproline levels in lung tissue. b, Left: quantification of neutrophils; middle: lymphocytes; and right: macrophages, in bronchoalveolar lavage fluid. For a and b, n = 3 animals for no bleomycin (bleo), n = 5 for bleo + vehicle (veh), and n = 6 for each of scrambled (scr) and Mmp13 siRNA (mmp13i) μMSCs. *P = 2.1 × 10−5 (a); P = 3.3 × 10−2 (b, left), P = 2.4 × 10−2 (b, middle); NS, P > 0.05 (b, right). c, Effects of gel-coated D1 mouse MSCs on hydroxyproline levels in lung tissue of Tnfα−/− host animals. d, Left: quantification of neutrophils; middle: lymphocytes; and right: macrophages, in bronchoalveolar lavage fluid. For c and d, n = 5 animals for each of no bleo, bleo + untreated (unt) μMSCs, and bleo + TNF-α-treated μMSCs; and n = 7 for bleo + veh. *P = (0.7–4.3) × 10−3 (c), P = (0.3–7.9) × 10−3 (d, left), P = (0.3–2.6) × 10−2 (d, middle); NS, P > 0.05 (d, right). Individual P values were derived from one-way Welch ANOVA followed by Dunnett T3 multiple comparisons test. Data are shown as mean ± s.d.