Fig. 3.

Ionizing radiation induces myofibroblast differentiation. Primary lung fibroblasts were exposed to 0, 3, and 7 Gy, and cell lysates and supernatants were collected at 5 days postradiation. A and B: α-SMA protein expression was analyzed by Western blot and densitometry. One representative experiment is shown (*P ≤ 0.05 by ANOVA compared with 0 Gy; n = 3). C: immunofluorescence staining for α-SMA (red) was performed on cell cultures exposed to 7-Gy radiation or transforming growth factor-β (TGF-β). Cell nuclei were stained with DAPI. D: Soluble collagen was measured in supernatants from irradiated cells cultures at 5 days postradiation using a Slot Blot Assay (*P ≤ 0.05 by ANOVA compared with 0 Gy; n = 3). E and F: total RNA was isolated from cells exposed to 7-Gy radiation at 3 days postradiation and quantitative real-time PCR was performed for Col1a1 and Col3a1 (*P ≤ 0.05 by t-test; n = 3).