Mono(2‐ethylhexyl)phthalate (MEHP), the active metabolite of di(2‐ethylhexyl)phthalate (DEHP), is known to exert cardiotoxicity. The aim of the present study was to investigate the role of forkhead box O3a (FOXO3a) in MEHP‐induced human AC16 cardiomyocyte injuries. MEHP reduced cell viability and mitochondrial membrane potential (ΔΨm), whereas it increased lactate dehydrogenase (LDH) leakage, production of reactive oxygen species (ROS), and apoptosis in cardiomyocytes. The expression of FOXO3a and its target genes, mitochondrial superoxide dismutase (Mn‐SOD) and apoptosis repressor with caspase recruitment domain (ARC), increased after MEHP exposure, but the expression of p‐FOXO3a protein was decreased. Overexpression of FOXO3a decreased the production of ROS and the apoptosis rate induced by MEHP, and the expression of Mn‐SOD and ARC was further increased after MEHP exposure. In contrast, knockdown of FOXO3a resulted in increased ROS production and apoptosis and suppressed the expression of Mn‐SOD and ARC in the presence of MEHP. However, overexpression or knockdown of FOXO3a did not affect MEHP‐induced loss of ΔΨm. In conclusion, the loss of ΔΨm and apoptosis are involved in MEHP‐induced cardiomyocyte toxicity. Activation of FOXO3a defends against MEHP‐induced oxidative stress and apoptosis by upregulating the expression of Mn‐SOD and ARC in AC16 cardiomyocytes.

中文翻译：

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邻苯二甲酸单（2-乙基己基）酯对叉头盒 O3a 的激活及其在人心肌细胞中对单（2-乙基己基）酯诱导的氧化应激和细胞凋亡的保护作用

邻苯二甲酸单（2-乙基己基）酯（MEHP）是邻苯二甲酸二（2-乙基己基）酯（DEHP）的活性代谢物，已知具有心脏毒性。本研究的目的是研究叉头盒 O3a (FOXO3a) 在 MEHP 诱导的人类 AC16 心肌细胞损伤中的作用。MEHP 降低了细胞活力和线粒体膜电位 (ΔΨm)，而它增加了乳酸脱氢酶 (LDH) 泄漏、活性氧 (ROS) 的产生和心肌细胞的凋亡。MEHP 暴露后 FOXO3a 及其靶基因、线粒体超氧化物歧化酶 (Mn-SOD) 和具有半胱天冬酶募集结构域 (ARC) 的凋亡抑制因子的表达增加，但 p-FOXO3a 蛋白的表达降低。FOXO3a 的过表达降低了 MEHP 诱导的 ROS 产生和细胞凋亡率，MEHP 暴露后 Mn-SOD 和 ARC 的表达进一步增加。相反，在 MEHP 存在下，FOXO3a 的敲低导致 ROS 产生和细胞凋亡增加，并抑制 Mn-SOD 和 ARC 的表达。然而，FOXO3a 的过表达或敲低不会影响 MEHP 诱导的 ΔΨm 损失。总之，ΔΨm 的丧失和细胞凋亡与 MEHP 诱导的心肌细胞毒性有关。FOXO3a 的激活通过上调 AC16 心肌细胞中 Mn-SOD 和 ARC 的表达来防御 MEHP 诱导的氧化应激和细胞凋亡。总之，ΔΨm 的丧失和细胞凋亡与 MEHP 诱导的心肌细胞毒性有关。FOXO3a 的激活通过上调 AC16 心肌细胞中 Mn-SOD 和 ARC 的表达来防御 MEHP 诱导的氧化应激和细胞凋亡。总之，ΔΨm 的丧失和细胞凋亡与 MEHP 诱导的心肌细胞毒性有关。FOXO3a 的激活通过上调 AC16 心肌细胞中 Mn-SOD 和 ARC 的表达来防御 MEHP 诱导的氧化应激和细胞凋亡。