Aspirin inhibits the mRNA expression of COL1A1, α-SMA and fibronectin in endometrial tissues. (A–C) The expression levels of (A) COL1A1, (B) α-SMA and (C) fibronectin in endometrial tissues were determined at the mRNA level by reverse transcription quantitative polymerase chain reaction analysis. The relative quantity of mRNA was calculated by comparison against the internal control, GAPDH. The mRNA levels of COL1A1, α-SMA and fibronectin were significantly inhibited in the endometrium tissues within the aspirin and oestradiol valerate therapy group (group B; n=28) compared with the oestradiol valerate therapy group (group A; n=26) following treatment. *P<0.05 vs. preoperative. #P<0.05 vs. group A. COL1A1, collagen type I α 1 chain; α-SMA, α-smooth muscle actin.