Figure 2.

Effect of TGF-β₁ on lung fibroblast proliferation. Proliferation was assessed 72 hours after the addition of TGF-β₁ at the indicated concentrations using a spectrophotometric assay in representative fibroblast lines from group I (a), group II (b), and group III (c). Results are expressed as percentage change compared to cells exposed to media alone. Mean absorbance at 650 nm for cells grown in media alone were 0.149 ± 0.004, 0.180 ± 0.012, and 0.349 ± 0.011 in groups I, II, and III, respectively. Each point represents the mean ± SEM for six replicate cultures. *, P < 0.05; **, P < 0.005; and ***, P < 0.000,5 respectively.