Objective:To study the effect of matrine on the expression of transcription factor Snail2 in peritoneal mesothelial cells epithelial-mesenchymal transition (EMT) induced by transforming growth factor-β1 (TGF-β1).Methods:Human peritoneal mesothelial cells were stimulated by TGF-β1 and treated with matrine. The experiment was divided into six groups (control group, TGF-β1-induced group (5 ng/ml), TGF-β1+0.4 mg/ml matrine intervention group, TGF-β1+0.6 mg/ml matrine intervention group, TGF-β1+0.8 mg/ml matrine intervention group and TGF-β1+1.0 mg/ml matrine intervention group). The expressions of Snail2, E-cadherin, α-smooth muscle actin (α-SMA), Fibronectin and collagen (Col)Ⅲ were detected by real-time fluorescence quantitative PCR and Western blotting. The protein phosphorylation levels of Smad2, Smad3 and extracellular signal-regulated kinase (ERK)1/2 were detected by Western blotting.Results:The mRNA and protein expressions of Snail2, α-SMA, Fibronectin and ColⅢ were up-regulated after being stimulated by TGF-β1 (5 ng/ml) in human peritoneal mesothelial cells, while the mRNA and protein expression of E-cadherin was down-regulated. TGF-β1 (5 ng/ml) could up-regulate the protein phosphorylation levels of Smad2, Smad3 and ERK1/2. Matrine (0.4, 0.6, 0.8, 1.0 mg/ml) could down-regulate the mRNA and protein expression levels of Snail2, α-SMA, Fibronectin and ColⅢ after being stimulated by TGF-β1 in human peritoneal mesothelial cells. Matrine could down-regulate the protein phosphorylation of ERK1/2, and up-regulate the mRNA and protein expression levels of E-cadherin with treatment of TGF-β1 in human peritoneal mesothelial cells.Conclusions:TGF-β1 can induce EMT of human peritoneal mesothelial cells. Matrine may inhibit TGF-β1-induced EMT of human peritoneal mesothelial cells by down-regulating the expression of Snail2 through the ERK1/2 signaling pathway.