| ?Objective?Inflammatory bowel disease(IBD) is characterized by a chronic relapsing non-specific inflammation. A growing number of researches have indicated that defective immune regulation and diminished barrier integrity deteriorate the pathogenesis of colitis. Injury of intestinal mucosal barrier has been shown to be an important pathogenic factor of IBD that initiate and propagate inflammatory responses. ROCK, as the downstream effector of RhoA, leads to contractile force generation by direct phosphorylation of myosin light chain(MLC). In addition,the NF-?B p65 pathway is also involved in MLCK-dependent barrier regulation.As a potent vasodilator peptide originally isolated from human pheochromocytoma,Adrenomedullin(AM) is now known to exert influence in a variety of physiological process, including cardiovascular protection, neovascularization, and suppression of inflammation and apoptosis. However, the underlying mechanism remains to be illustrated. The purpose of this study was to investigate the possible mechanism of AM to protect the intestinal epithelial barrier function in the rat model of ulcerative colitis and the effect of Compound Sophorae Flavescentis decoction(CSFD) on UC. ?Methods?Thirty-two Male Sprague-Dawley rats were randomly divided into four groups: normal control group, model group, AM group and CSFD group. Each group contained 8 rats. All the rats except the normal control group were administrated with TNBS to induce the colitis. Rats in normal control group used physiological saline instead. For 48 h after inducing colitis, in AM-treated group, AM(1.0?g of AM diluted in 1.0ml of saline) was injected into the lumen of the colon in the same way as the colitis induced. Compound Sophorae Flavescentis decoction was delivered into the CSFD group rats. Rats in normal control group and model group were received 1.0ml of saline instead. All of them were treated for seven consecutive days. Blood samples of rats were used to detect the levels of Serum tumor necrosis factor-?(TNF-?) and Interferon-?(IFN-?). Colon tissues were used to examinethe protein expression of RhoA, ROCK1, MLCK, NF-?Bp65 and Occludin by western blot analysis. ?Results?All the rats that induced by TNBS appeared the following symptoms such as profound and sustained weight loss, bradykinesia and mucusbloodandpus. Results suggested that levels of TNF-? and IFN-? in model rats were highly expressed rather than in the normal group(p<0.05), however, their expression were significantly down-regulated by AM and CSFD treatment(P<0.05). The expression level of RhoA, ROCKI, MLCK, NF-?Bp65 showed a significant increase in the model group compared with the normal group(P < 0.05), while treated with AM and CSFD clearly reduced the production. The expression of Occludin in the model rats was significantly decreased(p<0.05), while in AM and CSFD treatment group, the reduced Occludin expression appears to resume(p<0.05). However, there is no significant difference between AM group and CSFD group. ?Conclusion? 1. AM can alleviate TNBS induced intestinal inflammation in rats and improve the permeability of intestinal mucosa. 2. The suppression ofNF-?Bp65/MLCK signal pathway mediated by RhoA might be one possible mechanism contained in the process. 3. AM may change the intestinal mucosal tight junction and improve intestinal mucosal barrier function by regulating this signal pathway, and the traditional Chinese medicine CSFD has similar effect in colitis. |
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