Department of Medicine II, Klinikum Großhadern, University of Munich, Munich, Germany.
Hepatology. 2010 Nov;52(5):1758-68. doi: 10.1002/hep.23911.
NorUDCA (24-norursodeoxycholic acid), the C₂₃-homolog of ursodeoxycholic acid (UDCA), showed remarkable therapeutic effects in cholestatic Mdr2 (Abcb4) (multidrug resistance protein 2/ATP-binding cassette b4) knockout mice with sclerosing/fibrosing cholangitis. In contrast to UDCA, norUDCA is inefficiently conjugated in human and rodent liver, and conjugation has been discussed as a key step for the anticholestatic action of UDCA in cholestasis. We compared the choleretic, anticholestatic, and antiapoptotic properties of unconjugated and taurine-conjugated UDCA (C₂₄) and norUDCA (C₂₃) in isolated perfused rat liver (IPRL) and in natrium/taurocholate cotransporting polypeptide (Ntcp)-transfected human hepatoma (HepG2) cells. Taurolithocholic acid (TLCA) was used to induce a predominantly hepatocellular cholestasis in IPRL. Bile flow was determined gravimetrically; bile acids determined by gas chromatography and liquid chromatography/tandem mass spectrometry; the Mrp2 model substrate, 2,4-dinitrophenyl-S-glutathione (GS-DNP) was determined spectrophotometrically; and apoptosis was determined immunocytochemically. The choleretic effect of C₂₃-bile acids was comparable to their C₂₄-homologs in IPRL. In contrast, TnorUDCA, but not norUDCA antagonized the cholestatic effect of TLCA. Bile flow (percent of controls) was 8% with TLCA-induced cholestasis, and unchanged by coinfusion of norUDCA (14%). However, it was increased by TnorUDCA (83%), UDCA (73%) and TUDCA (136%). Secretion of GS-DNP was markedly reduced by TLCA (5%), unimproved by norUDCA (4%) or UDCA (17%), but was improved modestly by TnorUDCA (26%) or TUDCA (58%). No apoptosis was observed in IPRL exposed to low micromolar TLCA, but equivalent antiapoptotic effects of TUDCA and TnorUDCA were observed in Ntcp-HepG2 cells exposed to TLCA.
Conjugation is essential for the anticholestatic effect of norUDCA in a model of hepatocellular cholestasis. Combined therapy with UDCA and norUDCA may be superior to UDCA or norUDCA monotherapy in biliary disorders in which hepatocyte as well as cholangiocyte dysfunction contribute to disease progression.
研究 24-去甲熊去氧胆酸（norUDCA）在胆盐输出泵（BSEP）和多药耐药相关蛋白 2（MRP2）双重敲除小鼠胆汁淤积模型中的作用及可能的作用机制。
采用胆管结扎（BDL）和胆管内注射奥曲肽（octreotide）建立 BSEP 和 MRP2 双重敲除小鼠胆汁淤积模型，将小鼠随机分为假手术组（Sham）、模型组（BDL）、norUDCA 治疗组（BDL+norUDCA）和 UDCA 治疗组（BDL+UDCA），每组 8 只。给药组小鼠分别给予 norUDCA（100mg/kg）或 UDCA（200mg/kg）灌胃治疗，假手术组和模型组小鼠给予等体积的生理盐水灌胃，每天 1 次，连续给药 7 天。末次给药后 24 小时，处死小鼠，收集血清和肝脏组织。采用试剂盒检测血清中总胆红素（TBil）、直接胆红素（DBil）、丙氨酸氨基转移酶（ALT）、天门冬氨酸氨基转移酶（AST）、碱性磷酸酶（ALP）和γ-谷氨酰转肽酶（γ-GT）的水平；采用 HE 染色和天狼猩红染色观察肝组织病理学变化；采用实时荧光定量 PCR 法检测肝组织中 BSEP、MRP2、小异二聚体伴侣（SIDT1）、紧密连接蛋白（occludin）和 zonula occludens-1（ZO-1）mRNA 的表达；采用 Western blot 法检测肝组织中 BSEP、MRP2、SIDT1、occludin 和 ZO-1 蛋白的表达；采用免疫荧光法检测肝组织中 BSEP 和 MRP2 的表达和分布。
与假手术组相比，模型组小鼠血清 TBil、DBil、ALT、AST、ALP 和 γ-GT 水平显著升高（P<0.05），肝组织出现明显的胆汁淤积和炎症损伤；与模型组相比，norUDCA 和 UDCA 治疗组小鼠血清 TBil、DBil、ALT、AST、ALP 和 γ-GT 水平显著降低（P<0.05），肝组织损伤明显减轻；norUDCA 和 UDCA 治疗组小鼠肝组织中 BSEP、MRP2、SIDT1、occludin 和 ZO-1 mRNA 和蛋白的表达水平均显著升高（P<0.05）；免疫荧光结果显示，norUDCA 和 UDCA 治疗组小鼠肝组织中 BSEP 和 MRP2 的表达和分布均明显增加。
norUDCA 可通过上调 BSEP 和 MRP2 的表达和功能，改善 BSEP 和 MRP2 双重敲除小鼠胆汁淤积，其作用机制可能与激活核受体法尼醇 X 受体（FXR）有关。
Zotero 插件