Abstract：
BACKGROUND: Myocardial ischemia-reperfusion (I/R) causes damage to coronary capillary endothelial barrier and microvascular leakage (MVL), aggravating tissue injury and heart dysfunction. However, the effective strategy for protecting endothelium barrier of cardiac vasculature remains limited.
OBJECTIVE: This study aimed to explore the effect of Astragaloside IV (ASIV) on coronary MVL after cardiac I/R and the underlying mechanism.
METHODS: Sprague-Dawley (SD) rats were used for assessment of the efficacy of Astragaloside IV in protection of myocardial I/R injury, while human cardiac microvascular endothelial cells were applied to gain more insight into the underlying mechanism.
METHODS: Sprague-Dawley rats with or without pretreatment by ASIV at 10 mg/kg were subjected to occlusion of left coronary anterior descending artery followed by reperfusion. Endothelial cells were exposed to hypoxia and re-oxygenation (H/R). The distribution of junction proteins was detected by immunofluorescence staining and confocal microscope, the content of junction proteins was detected by Western blot, the level of adenosine triphosphate (ATP) was detected by ELISA, and the signal pathway related to permeability was detected by siRNA infection. The fluorescence intensity of FITC-albumin and FITC-Dextran was measured to evaluate the permeability of endothelial cells.
RESULTS: ASIV exhibited protective effects on capillary damage, myocardium edema, albumin leakage, leucocyte infiltration, and the downregulated expression of endothelial junction proteins after I/R. Moreover, ASIV displayed ability to protect ATP from depletion after I/R or H/R, and the effect of ASIV on regulating vascular permeability and junction proteins was abolished once ATP synthase was inhibited. Notably, ASIV activated the insulin-like growth factor 1 receptor (IGF1R) and downstream signaling after reoxygenation. Knocking IGF1R down abolished the effect of ASIV on restoration of ATP, junction proteins and endothelial barrier after H/R.
CONCLUSIONS: ASIV was potential to prevent MVL after I/R in heart. Moreover, the study for the first time demonstrated that the beneficial role of ASIV depended on promoting production of ATP through activating IGF1R signaling pathway. This result provided novel insight for better understanding the mechanism underlying the potential of ASIV to cope with cardiac I/R injury.
OBJECTIVE: This study aimed to explore the effect of Astragaloside IV (ASIV) on coronary MVL after cardiac I/R and the underlying mechanism.
METHODS: Sprague-Dawley (SD) rats were used for assessment of the efficacy of Astragaloside IV in protection of myocardial I/R injury, while human cardiac microvascular endothelial cells were applied to gain more insight into the underlying mechanism.
METHODS: Sprague-Dawley rats with or without pretreatment by ASIV at 10 mg/kg were subjected to occlusion of left coronary anterior descending artery followed by reperfusion. Endothelial cells were exposed to hypoxia and re-oxygenation (H/R). The distribution of junction proteins was detected by immunofluorescence staining and confocal microscope, the content of junction proteins was detected by Western blot, the level of adenosine triphosphate (ATP) was detected by ELISA, and the signal pathway related to permeability was detected by siRNA infection. The fluorescence intensity of FITC-albumin and FITC-Dextran was measured to evaluate the permeability of endothelial cells.
RESULTS: ASIV exhibited protective effects on capillary damage, myocardium edema, albumin leakage, leucocyte infiltration, and the downregulated expression of endothelial junction proteins after I/R. Moreover, ASIV displayed ability to protect ATP from depletion after I/R or H/R, and the effect of ASIV on regulating vascular permeability and junction proteins was abolished once ATP synthase was inhibited. Notably, ASIV activated the insulin-like growth factor 1 receptor (IGF1R) and downstream signaling after reoxygenation. Knocking IGF1R down abolished the effect of ASIV on restoration of ATP, junction proteins and endothelial barrier after H/R.
CONCLUSIONS: ASIV was potential to prevent MVL after I/R in heart. Moreover, the study for the first time demonstrated that the beneficial role of ASIV depended on promoting production of ATP through activating IGF1R signaling pathway. This result provided novel insight for better understanding the mechanism underlying the potential of ASIV to cope with cardiac I/R injury.
摘要：
背景：心肌缺血再灌注（I/R）导致冠状动脉毛细血管内皮屏障和微血管渗漏（MVL）的损害，加重组织损伤和心功能障碍。然而,保护心脏血管内皮屏障的有效策略仍然有限。
目的：本研究旨在探讨黄芪甲苷（ASIV）对心脏I/R后冠状动脉MVL的影响及其机制。
方法：用SD大鼠评价黄芪甲苷对心肌I/R损伤的保护作用。而人心脏微血管内皮细胞被用来更深入地了解潜在的机制。
方法：Sprague-Dawley大鼠接受或未接受10mg/kgASIV预处理后，左冠状动脉前降支闭塞，然后再灌注。将内皮细胞暴露于缺氧和再氧合(H/R)。免疫荧光染色和共聚焦显微镜检测连接蛋白的分布,蛋白质印迹法检测连接蛋白的含量，通过ELISA检测三磷酸腺苷（ATP）的水平，并通过siRNA感染检测与通透性相关的信号通路。测量FITC-白蛋白和FITC-葡聚糖的荧光强度以评估内皮细胞的通透性。
结果：ASIV对毛细血管损伤具有保护作用，心肌水肿，白蛋白渗漏,白细胞浸润,I/R后内皮连接蛋白表达下调此外，ASIV显示了I/R或H/R后保护ATP免于耗尽的能力，一旦ATP合酶被抑制，ASIV对血管通透性和连接蛋白的调节作用就被消除。值得注意的是,ASIV在复氧后激活胰岛素样生长因子1受体(IGF1R)和下游信号。敲低IGF1R消除了ASIV对ATP恢复的影响，H/R后连接蛋白与内皮屏障
结论：ASIV有可能预防心脏I/R后的MVL。此外，这项研究首次证明ASIV的有益作用依赖于通过激活IGF1R信号通路促进ATP的产生。该结果为更好地理解ASIV应对心脏I/R损伤的潜在机制提供了新的见解。
目的：本研究旨在探讨黄芪甲苷（ASIV）对心脏I/R后冠状动脉MVL的影响及其机制。
方法：用SD大鼠评价黄芪甲苷对心肌I/R损伤的保护作用。而人心脏微血管内皮细胞被用来更深入地了解潜在的机制。
方法：Sprague-Dawley大鼠接受或未接受10mg/kgASIV预处理后，左冠状动脉前降支闭塞，然后再灌注。将内皮细胞暴露于缺氧和再氧合(H/R)。免疫荧光染色和共聚焦显微镜检测连接蛋白的分布,蛋白质印迹法检测连接蛋白的含量，通过ELISA检测三磷酸腺苷（ATP）的水平，并通过siRNA感染检测与通透性相关的信号通路。测量FITC-白蛋白和FITC-葡聚糖的荧光强度以评估内皮细胞的通透性。
结果：ASIV对毛细血管损伤具有保护作用，心肌水肿，白蛋白渗漏,白细胞浸润,I/R后内皮连接蛋白表达下调此外，ASIV显示了I/R或H/R后保护ATP免于耗尽的能力，一旦ATP合酶被抑制，ASIV对血管通透性和连接蛋白的调节作用就被消除。值得注意的是,ASIV在复氧后激活胰岛素样生长因子1受体(IGF1R)和下游信号。敲低IGF1R消除了ASIV对ATP恢复的影响，H/R后连接蛋白与内皮屏障
结论：ASIV有可能预防心脏I/R后的MVL。此外，这项研究首次证明ASIV的有益作用依赖于通过激活IGF1R信号通路促进ATP的产生。该结果为更好地理解ASIV应对心脏I/R损伤的潜在机制提供了新的见解。
