Figure 2(a) shows that oral administration of OST decreased BLM-induced expression of TGF-β1 and α-SMA in the lungs of mice (P < 0.01). Vimentin is a marker of fibroblasts.  Figure 2(b) shows that OST administration decreased the expression of α-SMA in lung fibroblasts of BLM-treated mice (P < 0.001), blocking the switch of fibroblasts to myofibroblasts. Here, ACTA1 is linked to Bloom syndrome.