Thymidine exerts anti-doxorubicin-induced cardiomyopathy effect through the regulation of the PPAR signaling pathways and ferroptosis pathways

To evaluate the anti-cardiomyopathic activity of thymine (Thy) and to elucidate its mechanism of action. Transgenic zebra sh with enhanced green uorescent protein (EGFP)-labelled hearts (Tg (cmlc2: EGFP)) and wild-type AB zebrafish were used as experimental animals. A blank control group, a doxorubicin (DOX) model group, a dexrazoxane (DEX)-positive drug group and Thy drug treatment group were established. After treatment, indicators closely related to cardiac function, such as the pericardial area, heart rate, stroke volume, short-axis shortening (SAS) rate, and ejection fraction of the zebra sh in each group,were evaluated to determine the protective activity of Thy against DOX-induced cardiomyopathy. The pathways involved in the cardioprotective activity of Thy were analyzed via transcriptomics, and the regulatory effects of Thy on key genes were investigated using RT‒qPCR. The results indicated that Thy effectively relieved DOX-induced pericardial edema; reversed the effects of DOX on heart rate, stroke volume, SAS rate, ejection fraction, and blood velocity; and relieved DOX-induced myocardial ischemia, myocardial cell apoptosis and pathological structural changes in heart tissues. The transcriptome results indicated that the PPAR signaling and ferroptosis pathways were involved in the anti-DOX-induced cardiomyopathy effect of Thy. The RT‒qPCR results revealed that Thy regulated the mRNA expression levels of genes related to the PPAR signaling pathway and ferroptosis pathway (such as pparg, apoa1a, acsl5, pltp, and tfa). Thy may exert its anti-DOX-induced cardiomyopathy effect through the regulation of the PPAR signaling and ferroptosis pathways.

为评估胸腺嘧啶（thymine, Thy）的抗心肌病活性并阐明其作用机制，本研究以心脏标记增强绿色荧光蛋白（enhanced green fluorescent protein, EGFP）的转基因斑马鱼（Tg(cmlc2:EGFP)）及野生型AB品系斑马鱼作为实验动物，设置空白对照组、阿霉素（doxorubicin, DOX）模型组、右丙亚胺（dexrazoxane, DEX）阳性药物组与胸腺嘧啶给药组。给药处理后，对各组斑马鱼的心包面积、心率、每搏输出量、短轴缩短率（short-axis shortening, SAS）及射血分数等与心功能密切相关的指标进行检测，以评估胸腺嘧啶对阿霉素诱导心肌病的保护活性。通过转录组学分析胸腺嘧啶心脏保护作用的相关通路，并采用实时荧光定量聚合酶链式反应（RT‒qPCR）探究胸腺嘧啶对关键基因的调控作用。结果显示，胸腺嘧啶可有效缓解阿霉素诱导的心包水肿，逆转阿霉素对心率、每搏输出量、短轴缩短率、射血分数及血流速度的影响，并改善阿霉素诱导的心肌缺血、心肌细胞凋亡与心脏组织病理结构改变。转录组分析结果表明，过氧化物酶体增殖物激活受体（PPAR）信号通路与铁死亡（ferroptosis）通路参与了胸腺嘧啶抗阿霉素诱导心肌病的作用过程。实时荧光定量PCR结果显示，胸腺嘧啶可调控过氧化物酶体增殖物激活受体信号通路及铁死亡通路相关基因的mRNA表达水平，如pparg、apoa1a、acsl5、pltp及tfa。胸腺嘧啶可能通过调控过氧化物酶体增殖物激活受体信号通路与铁死亡通路发挥其抗阿霉素诱导心肌病的作用。