Data_Sheet_1_Triptolide increases resistance to bile duct ligation-induced liver injury and fibrosis in mice by inhibiting RELB.ZIP

Cholestasis is a common, chronic liver disease that may cause fibrosis and cirrhosis. Tripterygium wilfordii Hook.f (TWHF) is a species in the Euonymus family that is commonly used as a source of medicine and food in Eastern and Southern China. Triptolide (TP) is an epoxy diterpene lactone of TWHF, as well as the main active ingredient in TWHF. Here, we used a mouse model of common bile duct ligation (BDL) cholestasis, along with cultured human intrahepatic biliary epithelial cells, to explore whether TP can relieve cholestasis. Compared with the control treatment, TP at a dose of 70 or 140 μg/kg reduced the serum levels of the liver enzymes alanine transaminase, aspartate aminotransferase, and alkaline phosphatase in mice; hematoxylin and eosin staining also showed that TP reduced necrosis in tissues. Both in vitro and in vivo analyses revealed that TP inhibited cholangiocyte proliferation by reducing the expression of RelB. Immunohistochemical staining of CK19 and Ki67, as well as measurement of Ck19 mRNA levels in hepatic tissue, revealed that TP inhibited the BDL-induced ductular reaction. Masson 3 and Sirius Red staining for hepatic hydroxyproline showed that TP alleviated BDL-induced hepatic fibrosis. Additionally, TP substantially inhibited BDL-induced hepatic inflammation. In summary, TP inhibited the BDL-induced ductular reaction by reducing the expression of RelB in cholangiocytes, thereby alleviating liver injury, fibrosis, and inflammation.

胆汁淤积症（Cholestasis）是一种常见的慢性肝脏疾病，可引发肝纤维化与肝硬化。雷公藤（Tripterygium wilfordii Hook.f.，简称TWHF）隶属于卫矛科，在中国华东与华南地区常被用作药食两用资源。雷公藤内酯醇（Triptolide，简称TP）是TWHF中的环氧二萜内酯类化合物，亦是其核心活性成分。本研究采用胆总管结扎术（common bile duct ligation，简称BDL）诱导的胆汁淤积症小鼠模型，结合体外培养的人肝内胆管上皮细胞，探究TP是否能够缓解胆汁淤积症。与对照组相比，剂量为70 μg/kg或140 μg/kg的TP可降低小鼠血清中丙氨酸转氨酶、天冬氨酸转氨酶与碱性磷酸酶的水平；苏木精-伊红染色结果亦表明，TP可减轻组织坏死程度。体内外实验均证实，TP通过下调RelB转录因子（RelB）的表达抑制胆管上皮细胞增殖。对细胞角蛋白19（CK19）与Ki67抗原（Ki67）的免疫组织化学染色，以及肝组织Ck19 mRNA水平的检测结果均显示，TP可抑制BDL诱导的胆管反应。针对肝组织羟脯氨酸的Masson三色染色与天狼星红染色结果表明，TP可减轻BDL诱导的肝纤维化。此外，TP可显著抑制BDL诱导的肝脏炎症反应。综上，TP通过下调胆管上皮细胞中RelB转录因子（RelB）的表达，抑制BDL诱导的胆管反应，进而减轻肝脏损伤、肝纤维化与炎症反应。