ObjectiveTo investigate the effect of peroxisome proliferator-activated receptorγ(PPARγ) agonist on bile duct fibrosis induced by transforming growth factor-β1 (TGF-β1). MethodsPrimary cultures of bile duct fibroblast were treated with different concentrations of pioglitazone (PGZ) or 15-deoxy-Δ12, 14-prostaglandin J2 (15d-PGJ2) and then treated with TGF-β1. The mRNA levels of collagenⅠ(COLⅠ)、fibronectin (FN)、α-smooth muscle actin (α-SMA) and connective tissue growth factor (CTGF) were determined by RT-PCR. ResultsPGZ and 15-d-PGJ2 could down regulated the mRNA levels of COLⅠ, FN, α-SMA and CTGF induced by TGF-β1 (3 ng/mL). The same concentration of 15d-PGJ2 was a more potent inhibitor ofα-SMA and less potent inhibitor of COLⅠthan PGZ. But PGZ had the same effect as 15d-PGJ2 on CTGF. ConclusionPPARγagonist can prevent fibrosis induced by TGF-β1.