沙利度胺对大鼠TNBS结肠炎肠壁纤维化的影响及其机制

Effect of thalidomide on colon fibrosis in rats with chronic colitis induced by 2,4,6-trinitrobenzene sulphonic acid

目的:探讨沙利度胺对大鼠2,4,6-三硝基苯甲酸(2,4,6-trinitrobenzene sulphonic acids,TNBS)结肠炎肠壁纤维化的影响及其机制。方法:将60只Sprague-Dawley大鼠随机分为正常组、模型组、治疗组及对照组,每组15只。除正常组外,其余各组给予TNBS灌肠诱导大鼠结肠炎模型后,治疗组每日给予沙利度胺灌胃。28 d后处死所有大鼠取病变结肠组织,病理切片行HE染色及Masson染色,观察和评估结肠损伤及纤维化程度。Elisa及Western印迹检测TGF-β1,I型及III胶原,MMP-2,MMP-9及组织金属蛋白酶抑制剂(tissue inhibitors of metalloproteinases,TIMP-1)的表达水平。结果:与正常组相比,模型组大鼠结肠组织发生了明显的纤维化改变,TIMP-1,TGF-β1,I型及III胶原表达水平显著升高(均P<0.05);MMP-2及MMP-9蛋白的表达水平下降(均P<0.05)。治疗组大鼠结肠纤维化程度较模型组显著改善,TIMP-1,TGF-β1,I型及III胶原水平较模型组下降(均P<0.05);MMP-2及MMP-9蛋白水平较模型组升高(均P<0.05)。与对照组相比,模型组上述指标差异无统计学意义(均P>0.05)。结论:沙利度胺能够明显减轻大鼠TNBS结肠炎的肠壁纤维化程度,其主要作用机制是通过抑制TGF-β1的表达,从而抑制胶原的生成,并调节细胞外基质的生成降解平衡而达到抑制纤维化的作用。

Objective： To explore the effect of Thalidomide on the colon fibrosis in Sprague-Dawley （SD） rats with 2, 4, 6-trinitrobenzene sulphonic acids （TNBS）-induced colitis and the possible mechanism. Methods： A total of 60 SD rats randomly divided into 4 groups： a normal group, a model group, a treatment group and a control group （n=15 per group）. Except the normal group, the remaining rats were treated with TNBS to induce colitis. Then the rats in the treatment group received Thalidomide through intragastric administration. After 28 days, all the rats were killed and the samples of colons were collected. The pathological changes of the tissue from the colons were observed by haematoxylin-eosin（HE） and Masson staining. The protein levels of the TGF-β1, collagen Type Ⅰ, collagen Type Ⅲ, matrix metalloproteinases （MMP）-2, MMP-9 and tissue inhibitors of metalloproteinases （TIMP）-1 were determined by Western blot or ELISA. Results： There was significant inflammation reaction and fibrosis in the model group compared with the normal group （P〈0.05）. The expressions of TGF-β 1, ColA1, ColA3 and TIMP-1 were significant increased while the MMP-2 and MMP-9 were decreased in the model group than those in the normal group （all P〈0.05）, these phenomena were significantly reversed in the rats treated with Thalidomide （all P〈0.05 vs the model group）. The control group did not show such effects （all P〉0.05）. Conclusion： Thalidomide can significantly reduce the colon injury and suppress the collagen deposition in colon mesenchyma, which is related to inhibition of the expression of TGF-β1 and in turn to reduce the synthesis of collagen and restore the balance of MMPs/TIMPs.