Relative levels of hydroxyproline (HYP), α-smooth muscle actin (α-SMA) protein, α-SMA and pro-collagen III mRNA expressions in trans-differentiated myofibroblast (MF) treated by thalidomide (THD) or phosphate-buffered saline (PBS) (each experiment was repeated at least three times, data were shown as mean ± standard deviation). Group 1: human fetal lung fibroblast (HFL-F) was cultured with PBS for 144 h; group 2: HFL-F was cultured with 5 µg/l transforming growth factor (TGF)-β1 for 96 h, then TGF-β1 was removed and cells were incubated with PBS for additional 48 h; group 3: HFL-F was cultured with 5 µg/l TGF-β1 for 96 h, then TGF-β1 was removed and cells were incubated with 50 µg/l THD for another 48 h. (a) Relative levels of HYP protein, α-SMA mRNA and pro-collagen III mRNA; (b) reverse transcription–polymerase chain reaction: α-SMA and pro-collagen III mRNA; (c) Western blot: α-SMA protein.