Effect of SWCNT on lung fibrosis in mice. Mice were pharyngeal aspirated with Survanta® alone, Survanta®-dispersed SWCNT (SD-SWCNT) or acetone/sonication-dispersed SWCNT (AD-SWCNT), or Survanta®-dispersed ultrafine carbon black SD-UFCB) at the particle concentration of 10 μg/mouse. At 2 weeks after the treatment, mice were sacrificed and the lungs were isolated, lysed, and analyzed for collagen content by the Sircol® assay (A) and Western blotting (B). Equal amounts of total protein per sample were used. β-actin was used as a loading control for Western blotting. The blot signals were quantified by densitometry and mean data from three independent experiments were normalized to the result obtained in cells without treatment. Plots are mean ± S.D. (n = 3). *p < 0.05 versus non-treated control (No Tx).