摘要目的 探讨肝祖细胞在胆汁性肝纤维化发生中的分化取向及Notch信号通路对其调控作用.方法 (1)总胆管结扎制备大鼠胆汁淤积性肝纤维化模型,观察肝组织Notch信号通路的变化以及新生胆管上皮细胞的来源.(2)胆管结扎后腹腔注射DAPT(一种Notch信号通路阻断剂),观察Notch信号通路阻断后胆管上皮细胞的增殖及肝纤维化进展情况.结果 (1)胆管结扎后模型大鼠可见大量胆管增生并伴随炎性细胞浸润,且增生的胆管周围有大量的胶原沉积,免疫组织化学染色显示肝组织CK19、OV6、Sox9和上皮细胞黏附分子(EpCAM)表达明显增加,逆转录聚合酶链反应(RT-PCR)检测结果表明Notch信号通路明显活化.(2)采用DAPT抑制Notch信号通路后,胆管上皮细胞增生明显减轻,CK19、OV6、Sox9和EpCAM mRNA表达显著降低[分别为(10.2±0.7)比(22.3±0.8),(7.6±1.5)比(18.1±3.7),(1.4±0.4)比(4.1±1.1),(1.3±0.3)比(5.0±1.4),均P<0.01],且肝纤维化程度亦显著减轻.结论 在胆汁性肝纤维化,肝祖细胞可分化为胆管上皮细胞,Notch信号通路的活化对其发挥了关键作用,抑制Notch信号通路活化可能是治疗胆汁性肝纤维化的有效途径.

abstractsObjective To investigate differentiation direction of hepatic progenitor cells (HPCs) in cholestatic liver fibrosis (CLF), and the role of Notch signaling pathway in the differentiation of HPCs.Methods A CLF rat model was established by bile duct ligation (BDL) followed by monitoring changes of Notch signal pathway and the cellular origin of proliferating cholangiocytes.After intraperitoneal injection of DAPT (a Notch signaling inhibitor) after bile duct ligation, the progress of liver fibrosis and the proliferation of cholangiocytes after inhibition of the Notch pathway were analyzed.Results Data showed that bile duct proliferation gradually increased along with inflammatory cell infiltration and proliferating bile duct cells surrounded by abundant collagen in the BDL group.Immunostaining confirmed markedly increased expression of CK19, OV6, Sox9 and EpCAM.In addition, RT-PCR results showed that Notch signaling pathway was activated significantly.Once the Notch signaling pathway was inhibited by DAPT, bile duct proliferation markedly suppressed along with significantly decreased the mRNA expression of CK19, OV6, Sox9 and EpCAM, compared with BDL group [(10.2±0.7) vs.(22.3±0.8), (7.6±1.5) vs.(18.1±3.7), (1.4±0.4) vs.(4.1±1.1), (1.3±0.3) vs.(5.0±1.4), respectively, P<0.01].Moreover, liver fibrosis was also reduced significantly.Conclusion Notch signaling activation is required for HPCs differentiation into cholangiocytes in CLF and inhibition of the Notch signaling pathway may offer a therapeutic option for treating CLF.