OBJECTIVE:To explore the underlying mechanism of action of Tongxieyaofang decoction in rats with visceral hypersensitivity using proteomics technology.METHODS:Twenty-four female Sprague-Dawley rats were randomly divided into three groups:control group,irritable bowel syndrome (IBS) group and Tongxieyaofang treatment group.An IBS model,characterized as visceral hypersensitivity,was established using the odour of mothballs as conditional stimulation and colorectal distension combined with classic physical restraint as non-conditional stimulation.Rats were intragastrically treated with Tongxieyaofang (2 or 4 mL · kg-1 · d-1) for 4 weeks.On the 45th day,the rats were dissected and the colonic mucosal proteins were extracted.Differential protein spots were screened by fluorescent two-dimensional differential gel electrophoresis (2D-DIGE),and identified by matrix-assisted laser desorption/ionisation time of flight mass spectrometry (MALDI-TOF-MS).West blotting experiments were performed to verify the changes observed in 2D-DIGE and MALDI-TOF-MS.RESULTS:It was found that the visceral sensitivity of rats in the Tongxieyaofang treatment group (4 mL/kg) was lower than that in the IBS group (P ＜ 0.01).Sixty-one protein spots were differentially expressed between the IBS group and the Tongxieyaofang treatment group.Of these,23 spots were upregulated in the Tongxieyaofang treatment group,while 38 spots were downregulated.Three specific proteins were successfully identified from the five protein spots with the most obvious changes.The two upregulated proteins were transgelin (TAGLN) and acetaldehyde dehydrogenase 2 (AIdh2) and the downregulated protein was cytokeratin 8 (CK8).CONCLUSION:Tongxieyaofang can dose-dependently ameliorate visceral hypersensitivity in rats and the mechanism of action may involve the upregulation of TAGLN and Aldh2 and the downregulation of CK8.