Figure 1.

Senescent human lung fibroblasts induce lung fibrosis in mice. (A) IMR90 lung fibroblasts were exposed to γ-irradiation (20 Gy). Fourteen days later, senescence was confirmed by SABG staining (scale bar, 100 μm). (B) Immunodeficient (nude) mice were randomized to receive intratracheal instillation of proliferating human lung fibroblasts (IMR90) or senescent IMR90 (SEN-IMR90). PBS was used as a negative control. (C) Representative images of lung sections stained with Hematoxylin Eosin (HE) and Masson’s Trichrome (MT) from mice injected with IMR90 cells, SEN-IMR90 cells or PBS at 21 days post-injection. Scale bar 100 μm). (D) Modified Ashcroft score of MT staining in sections from mice injected with IMR90 or SEN-IMR90 cells at 21 days post-injection; n = 5. These data are part of a larger experiment presented in Triana-Martinez F, et al. [27]. (E) Hydroxyproline content in the right lung tissue of mice injected with SEN-IMR90 compared with IMR90 group at 21 days post-injection; n = 5 (left panel). These data are part of a larger experiment presented in Triana-Martinez F, et al. [27]. Relative expression of the mRNA coding for Col6a3 relative to Actin-b levels in lung cell extracts from mice injected with IMR90 and SEN-IMR90 cells at 21 days post-injection; n = 5 (right panel). All values are expressed as fold change relative to IMR90 group. Statistical significance was assessed by U-Mann Whitney test: ^*p < 0.05, ^****p < 0.0001. For further explanations, see text.