齐墩果酸可减轻胆管结扎小鼠的梗阻性胆汁淤积,可能是通过激活NRF2-MRPs和拮抗FXR来实现的。
Oleanolic acid attenuates obstructive cholestasis in bile duct-ligated mice, possibly via activation of NRF2-MRPs and FXR antagonism.
作者信息
Chen Pan, Li Jingjie, Fan Xiaomei, Zeng Hang, Deng Rongrong, Li Dongshun, Huang Min, Bi Huichang
机构信息
School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, PR China; Department of Pharmacy, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou 510080, PR China.
Center of Reproductive Medicine, the Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou 510655, PR China.
出版信息
Eur J Pharmacol. 2015 Oct 15;765:131-9. doi: 10.1016/j.ejphar.2015.08.029. Epub 2015 Aug 20.
Obstructive cholestasis is characterized by impairment of hepatic canalicular bile efflux and there are no clinically effective drugs to cure except surgeries. Previously we revealed that oleanolic acid (OA) protected against lithocholic acid (LCA)-induced intrahepatic cholestasis in mice. Cholestasis caused by LCA is characterized by segmental bile duct obstruction, whether OA possesses the beneficial effect on completed obstructive cholestasis induced by bile duct ligation (BDL) remains unknown. In this study, we demonstrated that BDL-induced mice liver pathological change, and increase in serum levels of ALT, AST and ALP were all significantly reduced by OA (20 mg/kg, i.p.). Meanwhile, OA also lowered total bilirubin and total bile acids levels in serum, as well as total bile acids level in liver, in contrast, urinary total bile acids output was remarkably up-regulated by OA. Gene expression analysis showed that OA caused significant increased mRNA expression of MRP3 and MRP4 located at hepatic basolateral membrane, and restoration of MRP2 and BSEP located at hepatic cannalicular membrane. Furthermore, significant NRF2 protein accumulation in nucleus was also observed in OA treated mice. In mice primary cultured hepatocytes, the effects of OA on MRP2, MRP3 and MRP4 expression were directly proved to be mediated via NRF2 activation, and BSEP downregulation induced by OA was in part due to FXR antagonism. Luciferase assay performed in Hep G2 cells also illustrated that OA was a partial FXR antagonist. Taken together, we conclude that OA attenuates obstructive cholestasis in BDL mice, possibly via activation of NRF2-MRPs and FXR antagonism.
梗阻性胆汁淤积的特征是肝胆小管胆汁流出受损,除手术外尚无临床有效的治愈药物。此前我们发现齐墩果酸(OA)可保护小鼠免受石胆酸(LCA)诱导的肝内胆汁淤积。LCA引起的胆汁淤积的特征是节段性胆管梗阻,OA对胆管结扎(BDL)诱导的完全性梗阻性胆汁淤积是否具有有益作用尚不清楚。在本研究中,我们证明OA(20mg/kg,腹腔注射)可显著减轻BDL诱导的小鼠肝脏病理变化以及血清ALT、AST和ALP水平的升高。同时,OA还降低了血清中的总胆红素和总胆汁酸水平以及肝脏中的总胆汁酸水平,相反,OA显著上调了尿中总胆汁酸的排出量。基因表达分析表明,OA导致位于肝基底外侧膜的MRP3和MRP4的mRNA表达显著增加,并使位于肝胆小管膜的MRP2和BSEP恢复。此外,在OA处理的小鼠中还观察到细胞核中NRF2蛋白的显著积累。在小鼠原代培养肝细胞中,直接证明OA对MRP2、MRP3和MRP4表达的影响是通过NRF2激活介导的,OA诱导的BSEP下调部分是由于FXR拮抗作用。在Hep G2细胞中进行的荧光素酶测定也表明OA是一种部分FXR拮抗剂。综上所述,我们得出结论,OA可能通过激活NRF2-MRPs和拮抗FXR减轻BDL小鼠的梗阻性胆汁淤积。