Objective To study the expression and localization of multi-drug resistance-associated protein 2 (Mrp2),multi-drug resistance-associated protein 3 ( Mrp3 ) changes and investigate the molecular mechanism of hyperbilirubinemia after hepatic ische-mia-reperfusion in rats. Methods Rats were divided into a sham operation group (Sham group) and a 30 min ischemia-reperfusion group (IR group). The levels of plasma DBIL and bile DBIL were detected. RT-PCR and Immunohistochemistry methods were used to detect the expression and localization of Mrp2 in the canalicular membrane and Mrp3 in the basolateral membrane. Results Compared with Sham group, the levels of plasma DBIL were significantly increased and the bile DBIL levels were significantly reduced 1 h ~ 1 d after reperfusion in IR group ( P < 0. 05 ). The expression of Mrp2 mRNA was significantly reduced 1 h ~ 6 h after reperfusion in IR group than in Sham group (P < 0. 05) ; No localization of Mrp2 protein in the canalicular membrane was found but it appeared in " vesicles" under the canalicular membrane 1 d after reperfusion. The expression of Mrp3 mRNA was significantly reduced 1 h ~ 1 d after reperfusion in IR group than in Sham group (P < 0. 05); At l h~l d after reperfusion, the staining intensity of Mrp3 protein was significantly increased in the basement membrane. Conclusion Down-regulation and abnormal localization of Mrp2 as well as up-regula-tion of Mrp3 were molecular mechanisms of hyperbilirubinemia after hepatic ischemia-reperfusion in rats.%目的 研究大鼠肝脏缺血再灌注后多耐药相关蛋白2(Mrp2)、多耐药相关蛋白3(Mrp3)表达及定位的改变,探讨肝缺血再灌注后发生高胆红素血症的分子机制.方法 实验分为假手术组(Sham组)和肝缺血30 min再灌注组(IR组).检测血浆和胆汁中DBIL含量.RT-PCR和免疫组织化学方法检测毛细胆管膜上Mrp2和基底膜上Mrp3的表达及定位.结果 与Sham组比较,IR于再灌注后1h～1d,血浆中DBIL含量明显升高,胆汁中DBIL含量明显下降(P＜0.05).再灌注后1h和6h,IR组Mrp2 mRNA表达明显低于Sham组(P＜0.05).再灌注后1d,IR组Mrp2蛋白在毛细胆管膜下呈“囊泡状”聚集,在毛细胆管膜上定位减少.再灌注后1h～1d,IR组Mrp3 mRNA表达明显高于Sham组(P＜0.05),IR组Mrp3蛋白在基底膜上明显着色,表达增加.结论 Mrp2的表达减少和定位异常以及Mrp3的表达增加是大鼠肝缺血再灌注后发生高胆红素血症的分子机制.
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