目的 探究茯苓酸改善果糖饮食诱导小鼠肝脏脂肪变性的作用及其机制。方法 将48只雄性C57BL/6小鼠随机分为对照组、模型组、非诺贝特（50 mg/kg）组及茯苓酸低、高剂量（25、50 mg/kg）组和茯苓酸（50 mg/kg）＋核因子E2相关因子2（nuclear factor erythroid 2-related factor 2，Nrf2）抑制剂ML385（30 mg/kg）组。对照组小鼠正常饮水，其余各组小鼠均给予30%果糖水溶液饲养，同时非诺贝特组和茯苓酸低、高剂量组小鼠分别ig相应药物治疗，茯苓酸＋ML385组小鼠在ig茯苓酸的同时ip ML385干预，1次/d，连续给药8周。实验结束后收集各组小鼠血清和肝脏样本，记录小鼠体质量和肝脏质量，计算肝脏指数；检测各组小鼠血清中天冬氨酸氨基转移酶（aspartate aminotransferase，AST）、丙氨酸氨基转移酶（alanine aminotransferase，ALT）活力和三酰甘油（triglyceride，TG）、总胆固醇（total cholesterol，TC）、低密度脂蛋白胆固醇（low-density lipoprotein cholesterol，LDL-C）、高密度脂蛋白胆固醇（high-density lipoprotein cholesterol，HDL-C）水平；检测各组小鼠肝脏中活性氧（reactive oxygen species，ROS）、丙二醛（malondialdehyde，MDA）、脂质过氧化物（lipid hydroperoxide，LPO）、谷胱甘肽（glutathione，GSH）、总超氧化物歧化酶（total superoxide dismutase，T-SOD）、总铁和亚铁离子（Fe²⁺）的水平；苏木素-伊红（hematoxylin-eosin，HE）染色、油红O染色和DAB加强法普鲁士蓝染色观察肝脏组织病理学变化；采用Western blotting检测各组小鼠肝脏组织中Nrf2、溶质载体家族7成员11（solute carrier family 7 member 11，SLC7A11）和谷胱甘肽过氧化酶4（glutathione peroxidase 4，GPX4）的蛋白表达。结果 与对照组比较，模型组小鼠体质量、肝脏质量和肝脏指数显著升高（P＜0.01），血清AST、ALT活力和TG、TC、LDL-C水平显著升高（P＜0.01），血清HDL-C水平显著降低（P＜0.01），肝脏组织中ROS、MDA、LPO、总铁和Fe²⁺的水平显著升高（P＜0.01），肝脏GSH和T-SOD的水平显著降低（P＜0.01），肝脏组织中Nrf2、SLC7A11和GPX4的蛋白表达水平显著降低（P＜0.01），小鼠肝脏呈严重的脂肪变性并伴有大量脂质蓄积和铁沉积。与模型组比较，茯苓酸给药后显著降低小鼠体质量、肝脏质量和肝脏指数（P＜0.05、0.01），显著降低血清AST、ALT活力和TG、TC、LDL-C水平（P＜0.01），显著升高血清HDL-C水平（P＜0.01），显著降低肝脏组织ROS、MDA、LPO、总铁和Fe²⁺的水平（P＜0.05、0.01），显著升高肝脏GSH和T-SOD的水平（P＜0.05、0.01）。同时，茯苓酸干预能够减轻果糖饮食小鼠肝脏脂肪变性、脂质蓄积和铁沉积，显著升高肝脏Nrf2、SLC7A11和GPX4的蛋白表达水平（P＜0.05、0.01），且给予Nrf2抑制剂干预能够明显逆转茯苓酸改善果糖饮食小鼠肝脏脂肪变性的作用。结论 茯苓酸能够通过激活Nrf2/SLC7A11/GPX4信号通路抑制铁死亡，从而改善果糖饮食小鼠肝脏脂肪变性。

Objective To investigate the effect and mechanism of pachymic acid ameliorating hepatic steatosis in fructose-fed mice. Methods A total of 48 male C57BL/6 mice were randomly divided into control group, model group, fenofibrate (50 mg/kg) group, pachymic acid low-, high-dose (25, 50 mg/kg) groups and pachymic acid (50 mg/kg) + nuclear factor erythroid 2-related factor 2 (Nrf2) inhibitor ML385 (30 mg/kg) group. The mice in control group were given normal drinking water, and the mice in the other groups were fed with 30% fructose water. Meanwhile, the mice in fenofibrate group and pachymic acid low-, high-dose groups were given the corresponding drugs by gavage once a day for eight weeks, while the mice in pachymic acid + ML385 group were given pachymic acid by gavage and ML385 by intraperitoneal injection once a day for eight weeks. At the end of the experiment, serum and liver samples were collected from each group of mice, body weight and liver weight were recorded, and the liver index was calculated. The activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT), as well as the levels of triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) in serum were detected. Moreover, the levels of reactive oxygen species (ROS), malondialdehyde (MDA), lipid hydroperoxide (LPO), glutathione (GSH), total superoxide dismutase (T-SOD), total iron and ferrous ion (Fe²⁺) were detected in liver tissues of mice in each group. Histopathological changes in liver were observed by hematoxylin-eosin (HE) staining, Oil red O staining and DAB-enhanced Prussian blue staining. Western blotting was used to detect the protein expression levels of Nrf2, solute carrier family 7 member 11 (SLC7A11) and glutathione peroxidase 4 (GPX4) in liver tissues of mice in each group. Results Compared with control group, mice in model group demonstrated markedly increased body weight, liver weight and liver index (P < 0.01), as well as significantly increased serum levels of AST, ALT, TG, TC and LDL-C (P < 0.01), while HDL-C level were markedly reduced (P < 0.01). In liver tissue, the levels of ROS, MDA, LPO, total iron and Fe²⁺ were markedly elevated (P < 0.01), the levels of GSH and T-SOD were markedly decreased (P < 0.01), and the protein expression levels of Nrf2, SLC7A11 and GPX4 were significantly decreased (P < 0.01). Meanwhile, mice in model group showed severe hepatic steatosis with extensive lipid accumulation and iron deposition. Compared with model group, pachymic acid administration markedly reduced body weight, liver weight and liver index in mice (P < 0.05, 0.01), and significantly decreased levels of AST, ALT, TG, TC, LDL-C in serum (P < 0.01), increased HDL-C level in serum (P < 0.01), reduced the levels of ROS, MDA, LPO, total iron and Fe²⁺ in liver tissue (P < 0.05, 0.01), increased the levels of GSH and T-SOD in liver tissue (P < 0.05, 0.01). Meanwhile, pachymic acid was able to attenuate hepatic steatosis, lipid accumulation and iron deposition, and significantly increased the protein expression levels of Nrf2, SLC7A11 and GPX4 in liver tissues (P < 0.05, 0.01). Intervention with Nrf2 inhibitor significantly reversed the effect of pachymic acid on improving hepatic steatosis in fructose-fed mice. Conclusion Pachymic acid ameliorates fructose-induced hepatic steatosis in mice by inhibiting ferroptosis via activating Nrf2/SLC7A11/GPX4 signaling.

R285.5

湖北省教育厅科研计划项目青年人才项目（Q20241207）；中药资源与中药化学湖北省重点实验室（湖北中医药大学）开放基金重点项目（KLRCCM2501）；武当特色中药研究湖北省重点实验室（湖北医药学院）开放基金重点项目（WDCM2024001）