Fu Yanan, Liu Tianshu, He Shukun, Zhang Yichan, Tan Yuting, Bai Ying, Shi Jiawei, Deng Wenhui, Qiu Jiani, Wang Zhen, Chen Yihan, Jin Qiaofeng, Xie Mingxing, Wang Jing
Department of Ultrasound Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
Clinical Research Center for Medical Imaging in Hubei Province, Wuhan, China.
Front Pharmacol. 2023 Jul 21;14:1189372. doi: 10.3389/fphar.2023.1189372. eCollection 2023.
Oxidative stress is crucial in experimental autoimmune myocarditis (EAM)-induced inflammatory myocardial injury. Ursolic acid (UA) is an antioxidant-enriched traditional Chinese medicine formula. The present study aimed to investigate whether UA could alleviate inflammatory cardiac injury and determine the underlying mechanisms. Six-week-old male BALB/c mice were randomly assigned to one of the three groups: Sham, EAM group, or UA intervention group (UA group) by gavage for 2 weeks. An EAM model was developed by subcutaneous injection of α-myosin heavy chain derived polypeptide (α-MyHC peptide) into lymph nodes on days 0 and 7. Echocardiography was used to assess cardiac function on day 21. The inflammation level in the myocardial tissue of each group was compared using hematoxylin and eosin staining (HE) of heart sections and Interleukin-6 (IL-6) immunohistochemical staining. Masson staining revealed the degree of cardiac fibrosis. Furthermore, Dihydroethidium staining, Western blot, immunohistochemistry, and enzyme-linked immunosorbent assay (ELISA) were used to determine the mechanism of cardioprotective effects of UA on EAM-induced cardiac injury, and the level of IL-6, Nrf2, and HO-1. In EAM mice, UA intervention significantly reduced the degree of inflammatory infiltration and myocardial fibrosis while improving cardiac function. Mechanistically, UA reduced myocardial injury by inhibiting oxidative stress (as demonstrated by a decrease of superoxide and normalization of pro- and antioxidant enzyme levels). Interestingly, UA intervention upregulated the expression of antioxidant factors such as Nrf2 and HO-1. experiments, specific Nrf2 inhibitors reversed the antioxidant and antiapoptotic effects of ursolic acid, which further suggested that the amelioration of EAM by UA was in a Nrf2/HO-1 pathway-dependent manner. These findings indicate that UA is a cardioprotective traditional Chinese medicine formula that reduces EAM-induced cardiac injury by up-regulating Nrf2/HO-1 expression and suppressing oxidative stress, making it a promising therapeutic strategy for the treatment of EAM.
氧化应激在实验性自身免疫性心肌炎（EAM）诱导的炎性心肌损伤中起关键作用。熊果酸（UA）是一种富含抗氧化剂的中药配方。本研究旨在探讨UA是否能减轻炎性心脏损伤并确定其潜在机制。将6周龄雄性BALB/c小鼠随机分为三组之一：假手术组、EAM组或UA干预组（UA组），通过灌胃给药2周。在第0天和第7天通过皮下注射α-肌球蛋白重链衍生多肽（α-MyHC肽）到淋巴结建立EAM模型。在第21天使用超声心动图评估心脏功能。使用心脏切片的苏木精和伊红染色（HE）以及白细胞介素-6（IL-6）免疫组织化学染色比较每组心肌组织中的炎症水平。Masson染色显示心脏纤维化程度。此外，使用二氢乙锭染色、蛋白质印迹、免疫组织化学和酶联免疫吸附测定（ELISA）来确定UA对EAM诱导的心脏损伤的心脏保护作用机制，以及IL-6、Nrf2和HO-1的水平。在EAM小鼠中，UA干预显著降低了炎性浸润程度和心肌纤维化，同时改善了心脏功能。机制上，UA通过抑制氧化应激减轻心肌损伤（表现为超氧化物减少以及促氧化和抗氧化酶水平正常化）。有趣的是，UA干预上调了Nrf2和HO-1等抗氧化因子的表达。在实验中，特异性Nrf2抑制剂逆转了熊果酸的抗氧化和抗凋亡作用,这进一步表明UA对EAM的改善是以Nrf2/HO-1途径依赖性方式进行的。这些发现表明，UA是一种心脏保护中药配方，通过上调Nrf2/HO-1表达和抑制氧化应激来减轻EAM诱导的心脏损伤，使其成为治疗EAM的一种有前景的治疗策略。
