COL3A1 and pulmonary fibrosis: Consistent with the induction of lung fibrosis by BLM, the transcript expression levels of various fibrogenic protein genes including Col1a1, Col3a1, Eln, Fn, Ctgf, as well as Txndc5, were significantly upregulated in BLM-treated mouse lungs (21 days post-BLM treatment, Fig. 2a).