牛磺酸对三硝基苯磺酸诱导的结肠炎大鼠肠纤维化的抑制作用

目的 探讨牛磺酸对三硝基苯磺酸(TNBS)诱导的结肠炎大鼠肠纤维化的影响.方法 32只SD大鼠均分为对照组、模型组、低剂量和高剂量牛磺酸组.对照组以0.9%氯化钠溶液灌肠,其余3组以TNBS灌肠诱导建立结肠炎模型.低剂量和高剂量牛磺酸组于造模前1周每日分别给予牛磺酸400和800 mg/kg干预,直至造模结束.观察大鼠临床表现及疾病活动指数(DAI),行结肠大体评分和组织学评分,检测大鼠结肠长度、结肠重量.测定结肠组织中羟脯氨酸(Hyp)、Ⅰ型胶原蛋白、转化生长因子-β1(TGF-β1)蛋白和mRNA、Smad3蛋白和mRNA水平.结果 与对照组相比,模型组大鼠体重减轻、DAI评分升高、结肠狭窄伴近端扩张、结肠长度缩短、结肠重量增加、大体评分也显著升高(P<0.01).牛磺酸干预后,大鼠体重、DAI评分、结肠长度等指标均有所改善.模型组纤维化评分为1.88±0.35.较对照组明显增加(0.25±0.46,P<0.01);低剂量和高剂量牛磺酸组纤维化评分分别为1.25±0.71和0.75±0.47,较模型组下降(P<0.05).模型组大鼠结肠Hyp、TGF-β1、Ⅰ型胶原蛋白、Smad3蛋白和mRNA含量均较低剂量和高剂量牛磺酸组明显上升(P值均<0.05).结论 牛磺酸能有效抑制TNBS诱导的结肠炎大鼠肠纤维化,其抗纤维化机制可能与下调TGF-β1、抑制TGF-β/Smad3通路有关,为解决克罗恩病肠纤维化和肠狭窄提供一定的实验依据.

Inhibitory effect of taurine on colonic fibrosis in rats with colitis induced by 2, 4, 6-trinitrobenzene sulphonic acid

Objective To investigate the effect of taurine on colonic fibrosis in rats with colitis induced by 2,4,6-trinitrobenzene sulphonic acid(TNBS). Methods Thirty-two SD rats were divided into normal control group, model group, low-dose (400 mg/kg) taurine group and high-dose (800 mg/kg) taurine group. Rats in normal group were administrated with 0.9% NaCl solution enema, and the other three groups received TNBS enema. The rats in low-dose and high-dose taurine groups were administrated with 400 mg/kg and 800 mg/kg of taurine daily, respectively, one week before TNBS enema. Morphology and disease activity index (DAI) were evaluated, and the colonic tissues were histologically examined. Colon length and weight of the rats were also measured. The concentrations of hydroxyproline, collagen type Ⅰ, transforming growth factor-betal(TGF-β1), and Smad3 protein and mRNA in colon tissues were tested. Results In comparison with control group, the body weight and colon length were decreased while DAI score and colon weight were increased obviously in model group (P`0.01). All above parameters were improved after intervention of taurine. The fibrotie score in model group (1.88±0.35) was significantly higher than that in control group (0.25±0.46), low-dose (1.25±0.71) and high-dose (0.75±0.47) taurine groups (all P values <0.05). High levels of hydroxyproline, collagen type Ⅰ, TGF-β1 and Smad3 were detected in model group compared with low-dose and high-dose taurine groups (all P values < 0.05). Conclusions Taurine is effective in prevention of colonic fibrosis induced by TNBS in rats, which is mediated by the down regulation of TGF-β1 and the inhibition of TGF-β/ Smad3 pathway. It may be beneficial in treatment of Crohn's disease with colonic fibrosis and strictures.