Department of Cardiology Heart Center, Zhujiang Hospital, Southern Medical University, Guangzhou 510280, PR China; Department of Cardiology, Heart Center, Changsha Central Hospital, Changsha 410004, PR China.
Department of Cardiology Heart Center, Zhujiang Hospital, Southern Medical University, Guangzhou 510280, PR China.
Biomed Pharmacother. 2018 Nov;107:1779-1785. doi: 10.1016/j.biopha.2018.05.113. Epub 2018 Sep 11.
Vascular smooth muscle cells (VSMCs) has been reported to be implicated in atherosclerotic plaque instability and rupture. Recently, it has been demonstrated that VSMCs block the progression of cardiac remodeling and thus promoting cardiac function in a rat myocardial infarction model. However, the detailed molecular mechanism of how VSMCs contributes to recovery in myocardial ischemia/reperfusion remains not fully understood.
We have isolated, identified and cultured VSMCs from rats to co-culture with rat cardiomyocyte H9C2. To culture H9C2 cells under hypoxia, we utilized CoCl-containing medium to culture for 8 h and then was replaced with normal media for additional 16 h. Cell viability was examined by MTT assay and apoptosis was determined by flow cytometry. Infarcted area of myocardial tissue was measured by TTC staining.
VSMCs was shown to promote cell viability and inhibit apoptosis of H9C2 cells under hypoxia, which exhibited upregulated anti-apoptotic protein Bcl-2 and autophagy-related protein p62, whereas pro-apoptotic protein cleaved caspase-3 and the level of LC3II/LC3I were downregulated. Then, we confirmed VSMCs played the contributory role in cell viability of H9C2 under hypoxia by secreting bFGF, which exerted its function through PI3K/Akt pathway. Finally, in vivo, the results demonstrated that VSMCs transplantation contributed to recovery of myocardial ischemia.
We determine that VSMCs promote recovery of infarcted cardiomyocyte through secretion of bFGF, which then activating PI3K/Akt pathway to inhibit apoptosis and autophagy. These findings provide more insights into the molecular mechanism underlying VSMCs contributing to recovery of myocardial I/R and facilitate developing therapeutical strategies for treating heart diseases.
血管平滑肌细胞（VSMCs）被报道与动脉粥样硬化斑块不稳定和破裂有关。最近，已经证明 VSMCs 可以阻止心脏重构的进展，从而在大鼠心肌梗死模型中促进心脏功能。然而，VSMCs 如何有助于心肌缺血/再灌注恢复的详细分子机制仍不完全清楚。
我们从大鼠中分离、鉴定和培养 VSMCs，与大鼠心肌细胞 H9C2 共培养。为了在低氧条件下培养 H9C2 细胞，我们使用含有 CoCl 的培养基培养 8 小时，然后用正常培养基再培养 16 小时。通过 MTT 测定法检测细胞活力，通过流式细胞术检测细胞凋亡。通过 TTC 染色测量心肌组织的梗死面积。
VSMCs 在低氧条件下可促进 H9C2 细胞的活力并抑制其凋亡，表现为抗凋亡蛋白 Bcl-2 和自噬相关蛋白 p62 的上调，而促凋亡蛋白 cleaved caspase-3 和 LC3II/LC3I 的水平下调。然后，我们通过 VSMCs 分泌 bFGF 证实了其在低氧下对 H9C2 细胞活力的贡献作用，bFGF 通过 PI3K/Akt 通路发挥其作用。最后，在体内，结果表明 VSMCs 移植有助于心肌缺血的恢复。
我们确定 VSMCs 通过分泌 bFGF 促进梗死心肌细胞的恢复，进而激活 PI3K/Akt 通路抑制细胞凋亡和自噬。这些发现为 VSMCs 有助于心肌 I/R 恢复的分子机制提供了更多的认识，并为治疗心脏病的治疗策略的发展提供了依据。
