This study was aimed to investigate the role of the delta-opioid receptor （DOR）-β-arrestinl-Bcl-2 signal transduction pathway in the pathogenesis of ulcerative colitis （UC） and the intervention effects of oxymatrine on UC. Forty Sprague-Dawley rats were divided into nor- mal group, model group, oxymatrine-treated group and mesalazine-treated group （n=10 each） at ran- dom. The rat UC model was established by intra-colonic injection of trinitrobenzene sulfonic acid in the model group and two treatment groups. The rats in oxymatrine-treated group were subjected to intramuscular injection of oxymatrine [63 mg/（kg·day）] for 15 days, and those in mesalazine-treated group given mesalazine solution [0.5 g/（kg·day）] by gastric lavage for the same days. Animals in normal group and model group were administered 3 mL water by gastric lavage for 15 days. On the 16th day, after fasting for 24 h, the rats were sacrificed for the removal of colon tissues. The expres- sion levels of DOR, β-arrestinl and Bcl-2 were determined in colon tissues by immunohistochemistry and real-time quantitative polymerase chain reaction （RT-PCR）, respectively. It was found that the expression levels of DOR, [3-arrestinl and Bcl-2 protein and mRNA were significantly increased in the model group as compared with the other groups （P〈0.05）. They were conspicuously decreased in both mesalazine-treated and oxymatrine-treated groups in contrast to the model group （P〈0.05）. No statistically significant difference was noted in these indices between mesalazine- and oxyma- trine-treated groups （P〉0.05）. This study indicated that the DOR-β-arrestinl-Bcl-2 signal transduc- tion pathway may participate in the pathogenesis of UC. Moreover, oxymatrine can attenuate the de- velopment of UC by regulating the DOR-β-arrestin 1-Bcl-2 signal transduction pathway.
