Restenosis is a serious problem in patients who have undergone percutaneous transluminal angioplasty. Endothelial injury resulting from surgery can lead to endothelial dysfunction and neointimal formation by inducing aberrant proliferation and migration of vascular smooth muscle cells. Exosomes secreted by mesenchymal stem cells have been a hot topic in cardioprotective research. However, to date, exosomes derived from mesenchymal stem cells (MSC-Exo) have rarely been reported in association with restenosis after artery injury. The aim of this study was to investigate whether MSC-Exo inhibit neointimal hyperplasia in a rat model of carotid artery balloon-induced injury and, if so, to explore the underlying mechanisms. Characterization of MSC-Exo immunophenotypes was performed by electron microscopy, nanoparticle tracking analysis and western blot assays. To investigate whether MSC-Exo inhibited neointimal hyperplasia, rats were intravenously injected with normal saline or MSC-Exo after carotid artery balloon-induced injury. Haematoxylin-eosin staining was performed to examine the intimal and media areas. Evans blue dye staining was performed to examine re-endothelialization. Moreover, immunohistochemistry and immunofluorescence were performed to examine the expression of CD31, vWF and α-SMA. To further investigate the involvement of MSC-Exo-induced re-endothelialization, the underlying mechanisms were studied by cell counting kit-8, cell scratch, immunofluorescence and western blot assays. Our data showed that MSC-Exo were ingested by endothelial cells and that systemic injection of MSC-Exo suppressed neointimal hyperplasia after artery injury. The Evans blue staining results showed that MSC-Exo could accelerate re-endothelialization compared to the saline group. The immunofluorescence and immunohistochemistry results showed that MSC-Exo upregulated the expression of CD31 and vWF but downregulated the expression of α-SMA. Furthermore, MSC-Exo mechanistically facilitated proliferation and migration by activating the Erk1/2 signalling pathway. The western blot results showed that MSC-Exo upregulated the expression of PCNA, Cyclin D1, Vimentin, MMP2 and MMP9 compared to that in the control group. Interestingly, an Erk1/2 inhibitor reversed the expression of the above proteins. Our data suggest that MSC-Exo can inhibit neointimal hyperplasia after carotid artery injury by accelerating re-endothelialization, which is accompanied by activation of the Erk1/2 signalling pathway. Importantly, our study provides a novel cell-free approach for the treatment of restenosis diseases after intervention.

中文翻译：

---

来自间充质干细胞的外泌体通过激活大鼠的Erk1 / 2信号通路来抑制新内膜增生。

在进行经皮腔内血管成形术的患者中，再狭窄是一个严重的问题。手术引起的内皮损伤可通过诱导血管平滑肌细胞异常增殖和迁移而导致内皮功能障碍和新内膜形成。间充质干细胞分泌的外来体一直是心脏保护研究的热门话题。然而，迄今为止，很少报道源自间充质干细胞（MSC-Exo）的外泌体与动脉损伤后的再狭窄有关。这项研究的目的是调查MSC-Exo是否能抑制大鼠颈动脉球囊所致损伤的新生内膜增生，如果是，则探讨其潜在机制。MSC-Exo免疫表型的表征是通过电子显微镜进行的，纳米颗粒跟踪分析和蛋白质印迹分析。为了研究MSC-Exo是否抑制新生内膜增生，在颈动脉球囊损伤后给大鼠静脉注射生理盐水或MSC-Exo。进行苏木精-伊红染色以检查内膜和中膜区域。进行伊文思蓝染料染色以检查再内皮化。此外，进行了免疫组织化学和免疫荧光检查CD31，vWF和α-SMA的表达。为了进一步研究MSC-Exo诱导的再内皮化，通过细胞计数试剂盒8，细胞划痕，免疫荧光和蛋白质印迹试验研究了潜在的机制。我们的数据表明，MSC-Exo被内皮细胞摄入，全身注射MSC-Exo可抑制动脉损伤后的内膜增生。Evans蓝染色结果表明，与生理盐水组相比，MSC-Exo可以加速再内皮化。免疫荧光和免疫组化结果表明，MSC-Exo上调CD31和vWF的表达，但下调α-SMA的表达。此外，MSC-Exo通过激活Erk1 / 2信号传导途径从机械上促进了增殖和迁移。免疫印迹结果表明，与对照组相比，MSC-Exo上调了PCNA，Cyclin D1，Vimentin，MMP2和MMP9的表达。有趣的是，Erk1 / 2抑制剂逆转了上述蛋白质的表达。我们的数据表明，MSC-Exo可以通过加速再内皮化（伴随着Erk1 / 2信号通路的激活）来抑制颈动脉损伤后的新生内膜增生。重要的是，我们的研究为介入后再狭窄疾病的治疗提供了一种新颖的无细胞方法。