多药耐药相关蛋白1在梗阻性黄疸大鼠肝组织中的表达及意义

Expression and significance of multidrug resistance-associated protein 1 in the liver tissues of rat obstructive jaundice models

目的探讨多药耐药相关蛋白1(multidrug resistanceassociated protein1,Mrp1)在梗阻性黄疸大鼠胆红素代谢中的作用。方法将80只Wistar大鼠完全随机分为假手术组(shamoperation,SHAM)、胆总管结扎组(commonbileductligation,CBDL)、胆流复通组(bilereflow,REF),测定各时相点血清前白蛋白(prealbumin,PA)、总胆红素(DBIL)以及尿样直接胆红素(DBIL),采用RTPCR和间接法免疫荧光染色分别在基因转录、蛋白表达及细胞膜定位上检测mrp1在大鼠肝组织中的表达情况。结果CBDL术后PA迅速下降(P<0.01);TBIL在CBDL术后急剧升高(P<0.01),峰值出现在术后7d,然后水平有所回落,尿中DBIL在梗阻期间一直上升(P<0.05);复通术后上述指标逐步好转,至术后7d接近或已达到正常水平;mrp1mRNA水平随着梗阻时间的延长明显升高,在梗阻解除后仍处于较高水平,免疫荧光结果显示Mrp1定位表达于肝细胞膜上,变化规律与mRNA一致(P<0.05)。结论在梗阻性黄疸以及梗阻解除早期,Mrp1介导了胆红素的排泄。

Objective To explore the role of multidrug resistance-associated protein 1 （ Mrpl ） on bilirubin metabolism in rat obstructive jaundiced （OJ） models. Methods Eighty Wistar male rats were randomly divided into three groups： sham operation group in which the common bile duct was educed but not ligated; common bile duct ligation （CBDL） group in which the common bile duct was ligated and cut off; bile reflow group in which on day 14 after common bile duct ligation operation, the internal drainage from common bile duct to duodenum by silica gel duct was performed. Serum prealbumin, serum total bilirubin and urine direct bilirubin were assayed routinely. The expressions of mrpl mRNA and protein were detected in the liver tissues by semi-quantitative RT-PCR and indirect immunofluorescence respectively. Results Serum prealbumin was descending significantly （P 〈 0. 01 ）, while serum total albumin and urine direct bilirubin were ascending （P 〈 0. 05 ） after common bile duct ligation. The level of total bilirubin peaked on postoperative day 7, followed by a moderate decline. After bile reflow, the above-mentioned indice were taking a gradually favourable turn and drew near to normal levels. The expression of mrpl mRNA grew stronger as the obstruction duration prolonged （ P 〈 0. 05 ）. After bile reflow, moderate level was maintained with a small amount of descent. A similar profile was found in immunofluorescence detection. Conclusion Mrpl might play a compensatory role in excreting bilirubin and other bile components in obstruction and early stage of obstruction removal, which might be an adaptive self-regulation mechanism in obstructive jaundice.