Fibrogenic response as assessed by cytokine release in BAL fluid and collagen accumulation in the lung of C57BL/6 mice following CNF, Crocidolite Asbestos or SWCNT exposure. A: TGF-β; B: Total collagen measured on day 28 post exposure. Open columns - exposure with SWCNT (40 μg/mouse); gray columns - exposure with CNF (120 μg/mouse); black columns - exposure with crocidolite asbestos (120 μg/mouse). Mice were exposed via pharyngeal aspiration to the indicated doses and animals were sacrificed 1, 7, and 28 days post exposure. Means ± SE (n = 6 mice per group). *p < 0.05 vs. control (PBS) exposed mice; αp < 0.05 vs. mice exposed to CNF, βp < 0.05 vs. mice exposed to asbestos.