P-糖蛋白在健康猪肝脏、肾脏和肠组织中的分布及其mRNA相对转录水平

Distribution and Relative mRNA Transcription Level of P-gp in Liver,Kidney and Intestines of Piglet

本研究旨在探讨P-糖蛋白(P-gp)在健康仔猪肝脏、肾脏和肠组织中的分布及mRNA相对转录水平的差异。选用5头60日龄健康三元杂交仔猪,采用免疫组织化学方法对猪肠道、肝脏和肾脏中的P-gp定位;gapdh为看家基因,采用Real-time RT-PCR方法检测mdr1基因在健康猪仔十二指肠、空肠、回肠、盲肠、结肠、直肠、肝脏和肾脏中的mRNA转录水平。结果表明:P-gp在肝脏主要分布于肝细胞间的胆小管膜;在肾脏主要分布于近端小管和远端小管细胞膜上;在小肠主要位于肠绒毛上皮细胞顶端及小肠腺腔面上皮细胞顶端;在大肠中主要分布于黏膜上皮细胞顶端和大肠腺上皮细胞顶端。mdr1在检测组织中均有转录,其转录量由高到低依次为回肠、结肠、肝脏、空肠、十二指肠、直肠、盲肠和肾脏。其中回肠转录量最高,且与十二指肠、直肠相比差异显著(P=0.017、P=0.014),与盲肠和肾脏相比差异极显著(P=0.005、P=0.001);mdr1在空肠、结肠和肝脏中的相对转录量与肾脏相比差异显著(P=0.046、P=0.018、P=0.030)。结果提示P-gp在健康仔猪肝脏、肾脏和小肠组织中的分布和表达可能对一些口服药物的体内过程产生影响,因此猪临床用药时应充分考虑P-gp介导的药物间相互作用及对口服药物生物利用度的影响。

This study was conducted to investigate the distribution of P-gp and the transcription level of mdrl mRNA in liver, kidney and intestines of healthy piglets. Five crossbred pigs （Large white × Landrace × Duroc） of approximately 9 weeks of age with an average body weight of 20 kg were used. The localization of P-gp in healthy piglets was studied by immunohistochemisty method. And real-time RT-PCR method was used with gapdh as house-keeping gene to detect the transcription level of mdrl mRNA. Immunocytochemical method using specific monoclonal and polyclonal antibodies against P-gp confirm high expression in liver, intestines and kidney of the porcine. In the porcine liver, only the apical membrane of the epithelial cells in the bile ducts was positive. In the kidney, immunoreactivity is obvious in the proximal and distal tubules. Inthe intestines, P-gp was localized in the apical membranes of the enterocytes and the epithelial cells of intestinal gland. The transcription level of mdrl mRNA ranked from high to low in all tissues was ileum, colon, liver, jejunum, duodenum, rectum, cecum and kidney. The mdrl mR- NA transcription level of ileum was obviously higher than those of cecum and kidney （P=0. 005, P=0. 001） and significantly higher than those of duodenum and rectum （P=0. 017, P=0. 014）. Also the transcription level of mdrl mRNA of kidney was significantly lower than those of jeju- num, colon and liver respectively （P=0. 046, P=0. 018, P=0. 030）. The results indicate that P-gp could be detected in all test tissues, but the mdrl transcription level is different. The high expression level of P-gp in ileum and liver could play an important role in drug disposition in body and induce drug-drug interaction in clinic.