辛伐他汀对大鼠结肠炎结肠纤维化的初步研究

Preliminary study on simvastatin in colitis fibrosis in rats

目的探讨辛伐他汀对2，4，6-三硝基苯磺酸（TNBs）诱导的大鼠结肠炎结肠纤维化的作用及机制。方法48只雄性SD大鼠均分为6组，分别为健康对照组、TNBS组、辛伐他汀治疗I组和治疗Ⅱ组（造模后0～21d，分别用辛伐他汀5mg／kg和20mg／kg治疗）、治疗Ⅲ组和治疗Ⅳ组（造模后7～21d，分别用辛伐他汀5mg／kg和20mg／kg治疗）。观察大鼠体质量变化及疾病活动指数（DAD，对大鼠结肠行大体评分、组织学损伤及纤维化评分。RT—PCR检测Ⅰ型胶原和结缔组织生长因子（cTGF）mRNA水平。Western印迹法检测Ⅰ型胶原、CTGF和磷酸化肌球蛋白磷酸酶目标亚单位-1（p-MYPT-1）蛋白的表达。组间比较采用单因素方差分析。结果与对照组相比，TNBS组大鼠结肠长度缩短，结肠质量增加，DAI评分、大体评分、组织学损伤及纤维化评分均显著升高，结肠组织中Ⅰ型胶原的表达水平也明显升高。辛伐他汀干预后，大鼠结肠长度和质量均有改善，DAI评分、大体评分、组织学损伤及纤维化评分、结肠组织中Ⅰ型胶原及CTGF的表达均比TNBS组降低，p-MYPT-1的表达在治疗Ⅰ组为0．68±0．22，治疗Ⅱ组为0．59±0．27，治疗Ⅲ组为0．71±0．20，治疗Ⅳ组为0．59±0．25，均低于TNBS组的O．97±0．30（F=5．169，P〈0．05）。4个治疗组之间差异无统计学意义（P〉0．05）。结论辛伐他汀能有效防治TNBS诱导的大鼠结肠炎结肠纤维化，机制可能与抑制Rho激酶活化、下调CTGF过表达有关。

Objective To investigate the role and mechanism of simvastatin on colonic fibrosis in rats with 2, 4, 6-trinitrobenzene sulphonic acid （TNBS） induced colitis. Methods Forty-eight healthy male Sprague-Dawley rats were evenly divided into six groups： control group, TNBS group, simvastatin treated group Ⅰ , group Ⅱ （from zero to 21 days after modeling, simvastatin 5 mg/kg or simvastatin 20 mg/kg treated）, group Ⅲ and group Ⅳ （from seven to 21 days after modeling, simvastatin 5 mg/kg or 20 mg/kg treated）. Body weight and disease activity index （DAD of the rats were inspected, and general colon, histological injury and fibrosis were scored. The expressions of collagen types Ⅰ and connective tissue growth factor （CTGF） at mRNA level were detected by reverse transcription-polymerase chain reaction （RT-PCR）. The expressions of collagen types Ⅰ , CTGF and phosphorylation of myosin phosphatase target subunit-1 （p-MYPT-1） at protein level were determined by Western blotting. The data were analyzed by one-way ANOVA. Results Compared with control group, the colon length shortened, while colon weight, DAI score, general colon score, histological injury and fibrosis score significantly increased in TNBS group. And the expressions of collagen types Ⅰ also obviously increased. After intervention of simvastatin, both the colon length and weight of rats were improved. The DAI score, general score, histological injury and fibrosis score were lower than those of TNBS group. The expressions of collagen types Ⅰ , CTGF and p-MYPT-1 （group Ⅰ ： 0.68 4±0.22; group Ⅱ： 0. 594±0. 27; group Ⅲ： 0.71±0.20; group Ⅳ： 0. 594±0.25） in colonic tissue were all lower than those of TNBS group （F=5. 169, P〈0. 05）. There were no statistical significance among four groups （all P〉0.05）. Conclusion Simvastatin can effectively prevent TNBS-induced rat colitis from colonic fibrosis, the mechanism may be related with Rho-kinase inhibition and down-regulation of CTGF over-expression.