非甾体抗炎药肠损伤大鼠模型小肠组织中蛋白酶激活受体2的表达与肥大细胞分布

Relationship of protease.activated receptor-2 and mast cell in the rat model of small intestinal mucosal damage by short-term administration of non-steroidal anti-inflammatory drug

目的观察蛋白酶激活受体2（PAR－2）和肥大细胞在双氯芬酸致小肠黏膜损伤大鼠模型小肠组织中的表达、分布及意义。方法随机数字表法将24只成年雄性sD大鼠随机分为空白对照组和模型组，每组12只，空白对照组按1ml／250g蒸馏水灌胃1次，模型组给予7．5mg·kg^-1·d^-1双氯芬酸灌胃1次，至第5天行腹腔注射麻醉，取末端回肠，采用甲苯胺蓝染色法测定小肠黏膜中肥大细胞的分布，并对肥大细胞进行计数；采用免疫组织化学、Western印迹、荧光定量PCR分析PAR-2在小肠黏膜组织中的定位、表达和mRNA的变化。结果模型组小肠黏膜肥大细胞数明显高于空白对照组（10．3±2．2比4．2±1．2，P〈0．05）。免疫组织化学结果显示PAR-2表达于黏膜表面上皮、隐窝上皮和固有层炎性细胞，阳性染色位于细胞质。模型组小肠黏膜中PAR-2mRNA表达高于空白对照组（2．63±0．26比1，P〈0．05），PAR-2蛋白表达高于空白对照组（24.3±2．4比17．5±3．5，P〈0．05）。结论PAR-2、肥大细胞参与了双氯芬酸致大鼠小肠黏膜损伤过程。PAR-2可能由肥大细胞分泌的类胰蛋白酶激活而参与非甾体抗炎药致小肠损伤的发病过程。

Objective To identify the expression and significance of protease-activated receptor-2 （PAR-2） and mast cell （MC） in the rat model of small intestinal mucosal damage by a short-term administration of dielofenac. Methods Twenty-four SD-rats were divided into 2 groups （ control group and model group, 12 rats each ） by random digit table. The rats in the control group were treated with 1 ml distilled water per 250 g, once a day while those in the model group diclofenac 7.5 mg/kg per day. Their terminal ileum was harvested at Day 5 after an intraperitoneal injection. Toluidine blue dyeing was employed to determine the distribution of MC and its count in intestinal mucous membrane, hnmunohistochemistry, Western blot and real-time PCR （polymerase chain reaction） were employed analyze the location, expression and change of PAR-2 mRNA in intestinal mucous membrane. Results The count of MC was obviously higher in the model group than that in the control group（10. 3±2.2 vs 4. 2±1.2, P 〈0. 05）. PAR-2 was expressed on the mucous surface, recesses epidermis and lamina propria inflammatory cells. And positive dyes were located within cytoplasm. As compared with the control group, the expression of PAR-2 mRNA was higher（ 2. 63±0. 26 vs 1, P 〈 0. 05 ）and its protein expression higher in the model group（ 24. 3±2. 4 vs 17.5±3.5, P 〈 0. 05 ）. Conclusion Both PAR-2 and mast cell are involved in the pathogenesis of small intestinal mucosa injury induced by diclofenac in rats. PAR-2 may be activated by tryptase released from mast cells and participate in the pathogenesis of small intestinal injury as induced by non-steroidal anti-inflammatory drugs.