Aspirin inhibits the protein expression levels of COL1A1, α-SMA, fibronectin and the TGF-β1-Smad2/Smad3 pathway in endometrial tissues. (A) The expression levels of COL1A1, α-SMA, fibronectin, TGF-β1, Smad2, p-Smad2, Smad3 and p-Smad3 in endometrial tissues were determined at the protein level by western blot analysis. (B–E) The relative protein quantities (COL1A1, α-SMA, fibronectin, TGF-β1) were calculated by comparison against the internal control, GAPDH. (F and G) The relative quantity of p-Smad2 and p-Smad3 were calculated by comparison against the total Smad2 and Smad3, respectively. The protein levels of the fibrosis markers (COL1A1, α-SMA, fibronectin), TGF-β1, p-Smad2/Smad2 and p-Smad3/Smad3, were significantly inhibited in the endometrium tissues in the aspirin and oestradiol valerate therapy group (group B; n=8) compared with the oestradiol valerate therapy group (group A; n=8) following treatment. *P<0.05 vs. preoperative. #P<0.05 vs. group A. Pre-op, preoperative; post-op, postoperative; COL1A1, collagen type I α 1 chain; α-SMA, α-smooth muscle actin; TGF-β1, transforming growth factor β1; p-, phosphorylated.