目的 探究莫诺苷改善果糖饮食诱导小鼠肾损伤的作用及其机制。方法 将48只雄性C57BL/6小鼠随机分为对照组、模型组、别嘌呤醇（25 mg/kg）组及莫诺苷低、高剂量（25、50 mg/kg）组和莫诺苷（50 mg/kg）＋谷胱甘肽过氧化酶4（glutathione peroxidase 4，GPX4）抑制剂RSL3（5 mg/kg）组。对照组小鼠正常饮水，其余各组小鼠均给予30%果糖水饲养，同时各给药组小鼠给予相应药物，1次/d，连续给药8周。实验结束后收集各组小鼠血清、尿液和肾脏样本，记录各组小鼠体质量、肾脏质量，并计算肾脏指数；检测各组小鼠血清中肌酐（creatinine，Cre）、尿素氮（blood urea nitrogen，BUN）和尿酸（uric acid，UA）的含量；检测各组小鼠尿液中尿蛋白的含量；同时检测各组小鼠肾脏中活性氧（reactive oxygen species，ROS）、丙二醛（malondialdehyde，MDA）、总超氧化物歧化酶（total-superoxide dismutase，T-SOD）、脂质过氧化物（lipid hydroperoxide，LPO）、总铁和亚铁离子（Fe²⁺）的水平；苏木素-伊红（hematoxylin-eosin staining，HE）染色、Masson染色和普鲁士蓝染色观察肾脏组织病理学变化；采用qRT-PCR检测各组小鼠肾组织中GPX4和溶质载体家族7成员11（solute carrier family 7 member 11，SLC7A11）的mRNA表达水平；采用Western blotting和免疫组化法检测各组小鼠肾组织中GPX4和SLC7A11蛋白的表达水平。结果 与对照组比较，模型组小鼠体质量、肾脏质量和肾脏指数显著升高（P＜0.01），血清Cre、BUN、UA和尿蛋白含量显著升高（P＜0.01），肾组织ROS、MDA、LPO、总铁和Fe²⁺的水平显著升高（P＜0.01）、T-SOD活力均显著降低（P＜0.01），肾脏GPX4和SLC7A11的mRNA和蛋白表达水平显著降低（P＜0.01）；同时，模型组小鼠肾脏肾小管扩张、肾小球纤维化并伴有铁沉积。与模型组比较，莫诺苷给药后显著降低小鼠体质量、肾脏质量和肾脏指数（P＜0.05、0.01），显著降低血清Cre、BUN、UA和尿蛋白的含量（P＜0.05、0.01），显著降低肾组织ROS、MDA、LPO、总铁和Fe²⁺的水平（P＜0.05、0.01），显著升高肾组织T-SOD活力（P＜0.01）。同时，莫诺苷能够减轻果糖饮食小鼠肾脏肾小管扩张、肾小球纤维化和铁沉积，显著升高肾脏GPX4和SLC7A11的mRNA和蛋白表达水平（P＜0.05、0.01）。给予GPX4抑制剂干预后能够明显逆转莫诺苷激活GPX4/SLC7A11信号通路抑制铁死亡从而改善果糖饮食小鼠肾功能异常和肾脏损伤的作用。结论 莫诺苷能通过调控GPX4介导的铁死亡从而改善果糖饮食小鼠肾损伤。

Objective To investigate the effect and mechanism of morroniside on ameliorating kidney injury in fructose-fed mice. Methods A total of 48 male C57BL/6 mice were randomly divided into control group, model group, allopurinol (25 mg/kg) group, morroniside low-dose (25 mg/kg) group, morroniside high-dose (50 mg/kg) group and morroniside (50 mg/kg) + glutathione peroxidase 4 (GPX4) inhibitor RSL3 (5 mg/kg) group. The mice in control group were given normal drinking water, and mice in the other groups were fed with 30% fructose water, while the mice in each treatment group were given corresponding drugs once a day for eight consecutive weeks. At the end of the experiment, serum, urine and kidney samples were collected from each group of mice, and body weight and kidney weight were recorded, the kidney index was calculated; The contents of creatinine (Cre), blood urea nitrogen (BUN) and uric acid (UA) in serum as well as the content of urinary protein in urine were detected, respectively. Meanwhile, the levels of reactive oxygen species (ROS), malondialdehyde (MDA), total-superoxide dismutase (T-SOD), lipid hydroperoxide (LPO), total iron, and ferrous ion (Fe²⁺) in kidney of mice in each group were detected. Histopathological changes in liver was observed by hematoxylin-eosin (HE) staining, Masson staining and Prussian Blue staining. qRT-PCR was used to detect the mRNA expressions of GPX4 and solute carrier family 7 member 11 (SLC7A11) in kidney tissue of mice in each group. Western blotting and immunohistochemistry were used to detect the protein expression levels of GPX4 and SLC7A11 in kidney tissue of mice in each group. Results Compared with control group, mice in model group showed significantly increased body weight, kidney weight and kidney index (P < 0.01), significantly increased contents of Cre, BUN, UA in serum and urinary protein (P < 0.01), significantly increased levels of ROS, MDA, LPO, total iron and Fe²⁺ in kidney tissues (P < 0.01), significantly decreased T-SOD activity (P < 0.01), and significantly reduced mRNA and protein expression levels of GPX4 and SLC7A11 in kidney tissues (P < 0.01). Meanwhile, the kidney of mice in model group showed kidney tubular dilatation, glomerular fibrosis and iron deposition. Compared with model group, morroniside significantly decreased body weight, kidney weight and kidney index (P < 0.05, 0.01), significantly decreased levels of Cre, BUN, UA in serum as well as the content of urinary protein in urine (P < 0.05, 0.01), significantly decreased the contents of ROS, MDA, LPO, total iron, and Fe²⁺ in kidney tissues (P < 0.05, 0.01), and significantly increased T-SOD activity in kidney tissues (P < 0.01). Meanwhile, morroniside was able to attenuate renal tubular dilatation, glomerular fibrosis and iron deposition, and significantly increased the mRNA and protein expression levels of GPX4 and SLC7A11 in kidney tissues (P < 0.05, 0.01). Intervention with GPX4 inhibitor (RSL3) could significantly reverse the effect of morroniside on inhibiting ferroptosis by activating GPX4/SLC7A11 signaling pathway to improve renal dysfunction and kidney injury in fructose-fed mice. Conclusion Morroniside can ameliorate kidney injury in fructose-diet mice by modulating GPX4-mediated ferroptosis.

R285.5

湖北省自然科学基金青年基金项目（2024AFB140）；中药资源与中药化学湖北省重点实验室开放基金重点项目（KLRCCM2401）；武当特色中药研究湖北省重点实验室（湖北医药学院）开放课题重点项目（WDCM2024001）