Fig. 6.

Vimentin is required for Cd-induced peribronchiolar fibrosis. A and B: IMR-90 cells were transfected with vimentin siRNA or NT-siRNA and followed by 20 μM of CdCl₂ treatment for 2 h (A) or 3 h and then allowed to recover for 48 h (B). Western blots were performed using antibodies shown above. C: the soluble collagen levels were evaluated by Sircol collagen assay (n = 5). **P < 0.01. D: wild-type (WT) and Vimentin^−/− mice (n = 5 of each group) were treated intratracheally with saline or CdCl₂ (0.009 mg/kg body wt) every other day for 8 wk. Cryosections from weeks 1, 2, 4, and 8 mice lungs were stained with collagen-1 or picro-sirius red. Bar = 100 μm. Representative photomicrographs from 5 animals on week 4 are shown. E: 3,3′-diaminobenzidine staining density was quantified and the average positive area density was calculated from 10 random areas. Densities are denoted in arbitrary units. **P < 0.01. F: WT and Vimentin^−/− mice (n = 5 of each group) were treated as above and airway resistance following methacholine challenge was measured. ##P < 0.01 vs. WT Cd mice with methacholine at 20 or 40 mg/ml. Horizontal bars indicate the mean values.