Division of Nephrology and National Clinical Research Center for Geriatrics, Kidney Research Institute, West China Hospital of Sichuan University, No.37 Guoxue Alley, Chengdu 610041, China.
Laboratory of Clinical Pharmacy and Adverse Drug Reaction, West China Hospital of Sichuan University, Chengdu 610041, China.
Phytomedicine. 2021 Nov;92:153739. doi: 10.1016/j.phymed.2021.153739. Epub 2021 Sep 11.
Triptolide is naturally isolated from Tripterygium wilfordii Hook F., possessing multiple biological activities. Hepatotoxicity is one of the main side effects of triptolide. However, the effect of triptolide on nonalcoholic fatty liver disease remains unknown (NAFLD).
This study aimed to observe the amelioration of triptolide against NAFLD and investigate the engaged mechanism.
Two typical animal models of NAFLD, obese db/db mice and methionine/choline-deficient (MCD) diet-fed mice, were used. Hepatic steatosis, inflammation, and fibrosis were evaluated by H&E and Masson staining. Oil red O staining and lipid extraction analysis were used to detect fat content in mice livers. Expression of lipid metabolism, inflammatory and fibrogenic genes was also detected by Real-time PCR and Western blotting, respectively. Phosphoproteomics, molecular docking, and TR-FRET assay were performed to provide further insight into how triptolide improved NAFLD.
Intraperitoneal injection of triptolide at a daily dose of 50 μg/kg significantly alleviated MCD diet-induced nonalcoholic steatohepatitis (NASH), but 100 μg/kg triptolide caused severe hepatotoxicity. Pathological staining confirmed low-dose triptolide treatment reducing hepatic lipid deposition, inflammation, and fibrosis in NASH. Serum biochemical analysis revealed a reduction in the level of liver enzymes and bilirubin. MCD also induced rising expression of typical genes and proteins related to fibrosis (fibronectin, α-SMA, collagens, TGF-β) and inflammation (ILs, TNF-α, MCP-1), which was suppressed by low-dose triptolide. Data from the proteomics/phosphoproteomics and TR-FRET assay indicated triptolide was a potential allosteric AMPK agonist to increase the phosphorylation on Thr172 residue, with the EC of 277.78 μM and 231.02 μM for AMPKα1 and AMPKα2, respectively. Moreover, triptolide exhibited an ability to activate AMPK and further led to increasing ACC1 phosphorylation in the liver. The positive results that triptolide ameliorated hepatic lipogenesis, fatty acid oxidation, and fibrosis of NAFLD via activating AMPK were further confirmed in db/db mice with 10-week intervention (50 μg/kg, i.v., twice a week).
This study demonstrates that dose-related triptolide as an allosteric AMPK agonist has the potential to alleviate NAFLD without hepatotoxicity.
雷公藤红素是从雷公藤中分离得到的，具有多种生物活性。肝毒性是雷公藤红素的主要副作用之一。然而，雷公藤红素对非酒精性脂肪性肝病（NAFLD）的影响尚不清楚。
本研究旨在观察雷公藤红素对 NAFLD 的改善作用，并探讨其相关机制。
采用两种典型的 NAFLD 动物模型，肥胖 db/db 小鼠和蛋氨酸/胆碱缺乏（MCD）饮食喂养的小鼠，通过 H&E 和 Masson 染色评估肝脂肪变性、炎症和纤维化。油红 O 染色和脂质提取分析用于检测小鼠肝脏中的脂肪含量。实时 PCR 和 Western blot 分别用于检测脂质代谢、炎症和纤维化基因的表达。通过磷酸化蛋白质组学、分子对接和 TR-FRET 测定进一步研究雷公藤红素改善 NAFLD 的作用机制。
腹腔注射 50μg/kg 的雷公藤红素可显著缓解 MCD 饮食诱导的非酒精性脂肪性肝炎（NASH），但 100μg/kg 的雷公藤红素会引起严重的肝毒性。病理染色证实，低剂量雷公藤红素治疗可减少 NASH 时肝内脂质沉积、炎症和纤维化。血清生化分析显示肝酶和胆红素水平降低。MCD 还诱导与纤维化（纤连蛋白、α-SMA、胶原、TGF-β）和炎症（ILs、TNF-α、MCP-1）相关的典型基因和蛋白表达升高，这些表达被低剂量雷公藤红素抑制。磷酸化蛋白质组学和 TR-FRET 测定的数据表明，雷公藤红素是一种潜在的变构 AMPK 激动剂，可增加 Thr172 残基的磷酸化，对 AMPKα1 和 AMPKα2 的 EC 分别为 277.78μM 和 231.02μM。此外，雷公藤红素能够激活 AMPK，进一步导致肝脏中 ACC1 磷酸化增加。在 10 周干预（50μg/kg，iv，每周两次）的 db/db 小鼠中，进一步证实了雷公藤红素通过激活 AMPK 改善 NAFLD 的肝内脂肪生成、脂肪酸氧化和纤维化的阳性结果。
本研究表明，雷公藤红素作为一种变构 AMPK 激动剂，具有缓解 NAFLD 而不产生肝毒性的潜力。
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