Levels of TGF-β1, a principal regulator of the lung fibrosis, significantly increased in the lung tissue in the silica-instilled animals compared to saline-instilled controls (p < 0.05 after 14 days, p < 0.01 after 28 days), while EGCG treatment caused a small but insignificant decrease (p > 0.05 after 14 and 28 days) (Figure 3). Here, TGFB1 is linked to pulmonary fibrosis.