Purpose: Endothelial-to-mesenchymal transition (EndMT) is an important mechanism underlying cardiac fibrosis. The anti-ischemic drug trimetazidine (TMZ) is reportedly useful in ventricular remodeling and associated with NADPH oxidase (NOX) 2. This study aimed to investigate the possible effect of TMZ on cardiac fibrosis exerted via the inhibition of NOX2-mediated EndMT.
Methods: A cardiac fibrosis model was established in Sprague-Dawley rats through a subcutaneous injection of isoproterenol (ISO, 5 mg/kg/d). Echocardiographic parameters, myocardial fibrosis, NOX2 expression and EndMT were assessed. An in vitro model of EndMT was developed using human umbilical vein endothelial cells (HUVECs) via treatment with transforming growth factor-β (TGF-β) at 10 ng/mL for 24 h. HUVECs were administrated with TMZ or TMZ and lentivirus, the expression of EndMT and related proteins was observed by wound healing assay, immunoblotting, and immunofluorescence.
Results: Rats injected with ISO exhibited severe interstitial cardiac fibrosis and perivascular fibrosis, decreased left ventricular ejection fraction, and increased NOX activity. TMZ treatment mitigated cardiac fibrosis, ameliorated left ventricular dysfunction, and reduced NOX activity. In addition, TMZ effectively inhibited EndMT in ISO-treated rat hearts and TGF-β-treated HUVECs, as manifested by increased CD31 expression, decreased α-SMA expression, and suppressed cell migration. Compared with the control group, the expression of NOX2, nuclear factor-κB (NF-κB), and Snail was increased in vivo and in vitro but decreased with TMZ treatment. Furthermore, the overexpression of NOX2 by lentivirus abolished the protective effects of TMZ on TGF-β-induced EndMT.
Conclusion: TMZ may ameliorate EndMT and ISO-induced cardiac fibrosis through the NOX2/NF-κB/Snail pathway. The findings of the study may provide new insights into the potential role of TMZ in the pathophysiology of cardiac fibrosis.

Keywords: trimetazidine, endothelial-to-mesenchymal transition, cardiac fibrosis, NADPH oxidase 2


中文翻译：

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曲美他嗪通过抑制 NOX2 介导的内皮-间质转化减少大鼠心脏纤维化

目的：内皮-间质转化（EndMT）是心脏纤维化的重要机制。据报道，抗缺血药物曲美他嗪 (TMZ) 可用于心室重构并与 NADPH 氧化酶 (NOX) 2 相关。本研究旨在研究 TMZ 通过抑制 NOX2 介导的 EndMT 对心脏纤维化的可能影响。
方法：通过皮下注射异丙肾上腺素 (ISO, 5 mg/kg/d) 在 Sprague-Dawley 大鼠中建立心脏纤维化模型。评估超声心动图参数、心肌纤维化、NOX2 表达和 EndMT。使用人脐静脉内皮细胞 (HUVEC) 通过 10 ng/mL 的转化生长因子-β (TGF-β) 处理 24 小时，开发了 EndMT 的体外模型。HUVECs与TMZ或TMZ和慢病毒一起给药，通过伤口愈合试验、免疫印迹和免疫荧光观察EndMT及相关蛋白的表达。
结果：注射 ISO 的大鼠表现出严重的间质心脏纤维化和血管周围纤维化，左心室射血分数降低，NOX 活性增加。TMZ 治疗减轻了心脏纤维化，改善了左心室功能障碍，并降低了 NOX 活性。此外，TMZ 有效抑制 ISO 处理的大鼠心脏和 TGF-β 处理的 HUVEC 中的 EndMT，表现为 CD31 表达增加、α-SMA 表达降低和抑制细胞迁移。与对照组相比，在体内和体外，NOX2、核因子-κB (NF-κB) 和 Snail 的表达增加，但随着 TMZ 处理而降低。此外，慢病毒对 NOX2 的过表达消除了 TMZ 对 TGF-β 诱导的 EndMT 的保护作用。
结论：TMZ 可通过 NOX2/NF-κB/Snail 通路改善 EndMT 和 ISO 诱导的心脏纤维化。该研究的结果可能为 TMZ 在心脏纤维化病理生理学中的潜在作用提供新的见解。

关键词：曲美他嗪，内皮-间质转化，心脏纤维化，NADPH氧化酶2