The study was conducted to investigate the level difference of multidrug resistance protein 2 (MRP2) proteins and mRNA expressions in the liver, duodenum, jejunum, ileum and colon of the healthy and E. Co/z-infected rats. Twenty healthy adult SD rats were randomly divided into control group (administered with sterile pathogen-free physiology saline) and E. Coli-iniec-ted group. The immunohistochemical and real time RT-PCR methods were used in this study. The results showed that MRP2 was expressed in all tissues of healthy and infected rats. Positive reaction of MRP2 protein was shown in the bile duct cell surface of liver (liver bile capillary membrane) and the mucosa of the intestines layer of healthy and infected rats, while positive reaction in the liver portal vein was weak. For the healthy rats, MRP2 was widely and highly expressed in the cell membrane of liver bile capillary membrane compared with that of the near portal vein. Strong positive reaction was found in the liver bile capillary membrane, portal areas and intestines mucosa layer. Compared with the healthy rats, positive reaction or weak positive reaction was shown in these areas of infected rats, but positive reaction was obviously weaker than those of thehealthy rats. MRP2 protein showed strong positive in liver, duodenum and jejunum and positive in ileum and colon of healthy rats. However, MRP2 protein showed positive in duodenum and jejunum and weak positive in liver, ileum and colon in infected rats. The expression level of MRP2 mRNA in liver and small intestines of the E. Coli-infected rats was significantly lower (P<0. 05) compared to that in healthy rats. All these results indicated that MRP2 transporter in SD rats could be down-regulated during the acute phase response to E. Coli infection.%本研究旨在探讨多药耐药相关蛋白2(MRP2)在健康和感染大肠杆菌的SD大鼠肝脏、十二指肠、空肠、回肠和结肠中的分布特点和mRNA表达水平.选用健康成年SD大鼠20只,随机分成健康对照组和大肠杆菌感染组,采用免疫组织化学和荧光定量PCR的方法检测了MRP2在大鼠肝脏和肠组织中的定位与表达.结果显示:MRP2在健康和感染大鼠不同组织中均有分布,主要见于肝脏的胆管面(肝脏毛细胆管的细胞膜)、肝脏门静脉区和各肠段的肠黏膜层,但蛋白表达水平不同.健康组大鼠MRP2在肝脏毛细胆管的细胞膜分布比门静脉区附近广泛,在肝脏毛细胆管的细胞膜和门 静脉区表达均为强阳性;在十二指肠和空肠的表达为强阳性,在回肠和结肠表达为阳性;与健康组相比,MRP2在感染组大鼠的蛋白表达水平均较弱,主要表现为十二指肠和空肠为阳性,回肠和结肠中为弱阳性,肝细胞的胆管面为阳性,肝脏门静脉区附近呈弱阳性.MRP2的mRNA在健康和大肠杆菌感染大鼠的肝脏和肠组织中均有表达,但表达水平也存在差异.与健康组大鼠相比,MRP2 mRNA表达量在大肠杆菌感染组大鼠肝脏和小肠中显著下调(P＜0.05).SD大鼠感染大肠杆菌后可引起肝脏、小肠组织中MRP2在mRNA和蛋白水平的表达下调.
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