Background

Dioscin, a steroidal saponin natural product, has various pharmacological activities, such as anti-inflammatory, antioxidant, lipid-lowering. However, little is known about its effects on myocardial infarction (MI) injury. Thus, the study aimed to investigate the protective effects and possible mechanisms of dioscin.

Methods

We evaluated protective effects of Dioscin on HL-1 cells after hypoxia based on MTT and ROS in vitro. In vivo, we ligated left anterior descending (LAD) of C57BL/6 mice to establish MI model and assess serum levels of LDH, CK-MB, cTnI, SOD, MDA and CAT treated by dioscin. In addition, myocardial damages were reflected by H&E, masson and ultrastructural examination and Electrocardiograph (ECG) was detected in MI mice. And the BMP4/NOX1 pathway was measured by western blotting, immunofluorescence assay and Real-time PCR. Furthermore, to investigate cardio-protective effects of dioscin via targeting BMP4, we transfected siBMP4 into HL-1 cells in vitro and injected BMP4 siRNA though tail veins in vivo.

Results

In vitro, dioscin significantly increased the viability of HL-1 cells and inhibited ROS level under hypoxia. In vivo, dioscin markedly reduced the elevation of ST segment and alleviated myocardial infarct area in mice. In terms of serology, dioscin evidently decreased LDH, CK-MB, cTnI, MDA levels, and increased SOD level. In addition, dioscin improved the pathological status of myocardial tissue and restrained the production of collagen fibers. Mechanism study proved that dioscin notablely regulated the levels of Nrf2, Keap1, HO-1, p-NF-κB, nNF-κB, TNF-α, IL-1β and IL-6 by down-regulating the protein levels of BMP4 and NOX1 against oxidative stress and inflammation. Further investigation showed that siBMP4 transfection diminished hypoxia and MI-induced oxidative and inflammation injury. The transfection decreased LDH, CK-MB and cTnI levels, improved ischemia T-wave inversion and reduced striated muscle necrosis, nucleus dissolution, collagen fibrosis and mitochondrial swelling in mice. In addition, siBMP4 decreased ROS and MDA levels, increased SOD and CAT levels and down-regulated mRNA levels of TNF-α, IL-1β and IL-6. Moreover, BMP4, NOX1 and nNF-κB protein levels were decreased and Nrf2 levels were increased by siBMP4.

Conclusion

Our study confirmed that dioscin showed an outstanding anti-myocardial infarction effect via regulating BMP4/NOX1-mediated oxidative stress and inflammation, which has a promising application value and development prospect against MI injury in the future.

中文翻译：

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薯蓣皂苷通过调节 BMP4/NOX1 介导的氧化应激和炎症减轻心肌梗死损伤

背景

薯蓣皂苷是一种甾体皂甙天然产物，具有抗炎、抗氧化、降脂等多种药理活性。然而，人们对其对心肌梗死 (MI) 损伤的影响知之甚少。因此，该研究旨在调查薯蓣皂苷的保护作用和可能的机制。

方法

我们在体外基于 MTT 和 ROS 评估了薯蓣皂苷对缺氧后 HL-1 细胞的保护作用。在体内，我们结扎C57BL/6小鼠的左前降支（LAD）建立心肌梗死模型，并评估薯蓣皂苷处理的LDH、CK-MB、cTnI、SOD、MDA和CAT的血清水平。此外，H&E、masson和超微结构检查反映了心肌损伤，并在MI小鼠中检测到心电图（ECG）。并通过蛋白质印迹、免疫荧光测定和实时荧光定量PCR检测BMP4/NOX1通路。此外，为了研究薯蓣皂苷通过靶向 BMP4 的心脏保护作用，我们在体外将siBMP4 转染到 HL-1 细胞中，并在体内通过尾静脉注射 BMP4 siRNA 。

结果

在体外，薯蓣皂苷显着提高了HL-1细胞的活力并抑制了缺氧条件下的ROS水平。体内,薯蓣皂苷显着降低小鼠ST段抬高,减轻心肌梗死面积。血清学方面，薯蓣皂苷明显降低LDH、CK-MB、cTnI、MDA水平，升高SOD水平。此外，薯蓣皂苷改善了心肌组织的病理状态，抑制了胶原纤维的产生。机制研究证明薯蓣皂苷通过下调BMP4和NOX1蛋白水平显着调节Nrf2、Keap1、HO-1、p-NF-κB、nNF-κB、TNF-α、IL-1β和IL-6的水平抗氧化应激和炎症。进一步的研究表明，siBMP4 转染减少了缺氧和 MI 诱导的氧化和炎症损伤。转染降低了 LDH、CK-MB 和 cTnI 水平，改善了缺血 T 波倒置，减少了横纹肌坏死、细胞核溶解、小鼠胶原纤维化和线粒体肿胀。此外，siBMP4 降低了 ROS 和 MDA 水平，增加了 SOD 和 CAT 水平，并下调了 TNF-α、IL-1β 和 IL-6 的 mRNA 水平。此外，通过 siBMP4，BMP4、NOX1 和 nNF-κB 蛋白水平降低，Nrf2 水平升高。

结论

我们的研究证实薯蓣皂苷通过调节BMP4/NOX1介导的氧化应激和炎症表现出显着的抗心肌梗死作用，在未来抗心肌梗死损伤方面具有良好的应用价值和发展前景。