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目的探索儿茶素单体表没食子儿茶素没食子酸酯(EGCG)对炎症性肠病(IBD)模型大鼠肠黏膜的保护作用及机制。方法将72只健康 SD 大鼠随机分为正常对照组,模型组,药物阳性对照组,大、小剂量(100、50 mg/kg)EGCG 组及 EGCG 预处理组,每组12只,以三硝基苯磺酸(TNBS)灌肠制作大鼠 IBD 模型。灌肠用药2周后,评价各组大鼠肠黏膜病理组织学表现及评分;应用免疫组织化学法和半定量逆转录(RT)-PCR 法分别从蛋白、mRNA 水平检测各组肠黏膜细胞环氧合酶(COX)-2表达水平的变化。结果不同剂量 EGCG 灌肠均能不同程度改善 IBD 模型大鼠肠黏膜病理组织学征象,其中模型组,EGCG 大、小剂量组组织学评分为6.8±1.0、3.6±0.8、4.1±1.0,后两者与模型组相比差异均有统计学意义(均 P<0.05),均能抑制肠黏膜细胞 COX-2的蛋白和 RNA表达水平,且与用药剂量呈一定量效关系;其中以 EGCG 预处理组的效果最好(P<0.01)。结论EGCG 对 IBD 模型大鼠肠黏膜有保护作用,该作用可能是通过抑制 COX-2的活性实现。
Objective To explore the protective effect of epigallocatechin gallate (EGCG) on the intestinal mucosa in rats with inflammatory bowel disease (IBD) and its mechanism. Methods 72 healthy SD rats were randomly divided into normal control group, model group, drug-positive control group, large and small dose (100,50 mg / kg) EGCG group and EGCG pretreatment group, 12 rats in each group, Nitrobenzene sulfonic acid (TNBS) enema to make rat IBD model. Two weeks after the administration of enema, the pathological changes of intestinal mucosa of rats in each group were evaluated and scored. Immunohistochemistry and semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) Changes in the expression of COX - 2. Results Different doses of EGCG enema could improve the pathological changes of intestinal mucosa in IBD model rats. The histological scores of model group and EGCG large and small dose groups were 6.8 ± 1.0, 3.6 ± 0.8 and 4.1 ± 1.0 respectively, Compared with the model group, the difference was statistically significant (all P <0.05), both inhibited the expression of COX-2 protein and RNA in intestinal mucosa cells, and dose-dependent manner and a dose-effect relationship; EGCG pretreatment group The best effect (P <0.01). Conclusion EGCG has a protective effect on intestinal mucosa in IBD model rats, which may be through inhibiting the activity of COX-2.