上海中医药大学张建革小组揭示了华蟾毒配基通过Keap1-Nrf2-TFR1/ARE轴调节小胶质细胞氧化还原稳态，改善脑缺血再灌注损伤。相关论文于2025年11月10日发表在《中国药理学报》杂志上。

在这项研究中，课题组人员研究了RBG对CIRI进展的神经保护作用及其潜在机制。通过短暂性大脑中动脉闭塞（tMCAO）建立大鼠CIRI模型，然后给予RBG（2.6或4.0 mg·kg^-1·d^-1，灌胃）治疗5天。研究组发现，RBG显著减少脑梗死体积，恢复神经功能缺损，减轻tMCAO大鼠的神经元损失。定量蛋白质组学分析和扎实的实验数据显示，RBG通过改变转录因子Nrf2与转铁蛋白受体蛋白1 （TFR1）启动子区域内抗氧化反应元件（ARE）的结合亲和力来调节小胶质细胞铁稳态。在氧葡萄糖剥夺/再灌注（OGD/R）条件下的BV2细胞中，RBG(5、10和20μM)通过增加Nrf2和下游抗氧化剂HO-1、NQO1、GCLC和GCLM的表达，以剂量依赖性调节铁代谢，从而恢复氧化还原稳态。

课题组人员发现RBG通过与Keap1的Cys297残基共价结合激活Nrf2信号通路，这在BV2细胞的定点突变中得到了证实。在受OGD/R作用的BV2-PC12细胞共培养体系中，RBG (20μM)可有效缓解BV2细胞的凋亡，而Nrf2敲低可消除RBG的神经保护作用。同样，抑制Nrf2主题化ML385显著降低RBG诱导的tMCAO大鼠神经行为改善。他们的研究结果表明，RBG是Keap1-Nrf2-TFR1/ARE轴的一种新的调节剂，并表明RBG通过其对小胶质内平衡的影响，对CIRI具有良好的神经保护潜力。

据介绍，脑缺血再灌注损伤（CIRI）是一个重大的临床挑战，小胶质细胞稳态在其病理进展中起着关键作用。在中医的临床实践中，蟾精被广泛用作强心剂、镇痛剂和抗肿瘤剂。华蟾毒配基（RBG）是一种从维生素b中提取的蟾二烯内酯类化合物，具有广泛的药理活性，包括抗肿瘤、抗炎和心血管保护作用。

附：英文原文

Title: Resibufogenin ameliorates cerebral ischemia-reperfusion injury by modulating microglial redox homeostasis via Keap1-Nrf2-TFR1/ARE axis

Author: Chen, Yao, Shi, Wen-qing, Zhang, Pei, Wang, Ran, Ye, Wen-bo, Lin, Guo-qiang, Peng, Shou-jiao, Zhang, Jian-ge

Issue&Volume: 2025-11-10

Abstract: Cerebral ischemia-reperfusion injury (CIRI) represents a significant clinical challenge, with microglial homeostasis playing a critical role in its pathological progression. Venenum bufonis (VB) has been extensively utilized as a cardiotonic, analgesic, and antineoplastic agent in the clinical practice of traditional Chinese medicine. Resibufogenin (RBG) is a bufadienolide compound derived from VB that has a wide range of pharmacological activities, including antitumor, anti-inflammatory, and cardiovascular protective effects. In this study, we investigated the neuroprotective effects of RBG on the progression of CIRI and the underlying mechanisms. A CIRI model was established in rats by transient middle cerebral artery occlusion (tMCAO), after which the rats were administered RBG (2.6 or 4.0mg·kg1·d1, i.g.) for 5 days. We showed that RBG administration markedly reduced cerebral infarct volume, restored neurological deficits, and mitigated neuronal loss in tMCAO rats. Quantitative proteomic analysis and robust experimental data revealed that RBG modulated microglial iron homeostasis by altering the binding affinity of the transcription factor Nrf2 to the antioxidant response element (ARE) within the promoter region of transferrin receptor protein 1 (TFR1). In BV2 cells under oxygen-glucose deprivation/reperfusion (OGD/R) conditions, RBG (5, 10, and 20μM) dose-dependently modulated iron metabolism by increasing the expression of Nrf2 and the downstream antioxidants HO-1, NQO1, GCLC, and GCLM, thus restoring redox homeostasis. We found that RBG activated the Nrf2 signaling pathway by covalently binding to the Cys297 residue of Keap1, which was confirmed by site-directed mutagenesis in BV2 cells. In a BV2-PC12 cell coculture system subjected to OGD/R, RBG (20μM) effectively alleviated neuronal apoptosis, whereas Nrf2 knockdown in BV2 cells abrogated the neuroprotective effect of RBG. Similarly, inhibition of Nrf2 using ML385 markedly diminished RBG-induced improvements in neurological behavior in tMCAO rats. Our results identify RBG as a new modulator of the Keap1-Nrf2-TFR1/ARE axis and suggest that RBG has promising neuroprotective potential against CIRI through its effects on microglial homeostasis.

DOI: 10.1038/s41401-025-01689-2

Source: https://www.nature.com/articles/s41401-025-01689-2