低氧预处理骨髓间充质干细胞改善小鼠脑侧支循环和脑卒中预后。
Hypoxia-Preconditioned Bone Marrow Mesenchymal Stem Cells Improved Cerebral Collateral Circulation and Stroke Outcome in Mice.
机构信息
Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, China (H.T., X.Y., J.Z., Xiran Liu, L.L.).
China National Clinical Research Center for Neurological Diseases, Beijing (H.T., X.Y., J.Z., Xin Liu, L.L.).
出版信息
Arterioscler Thromb Vasc Biol. 2023 Jul;43(7):1281-1294. doi: 10.1161/ATVBAHA.122.318559. Epub 2023 May 25.
BACKGROUND
Adequate collateral circulation can remarkably improve patient prognoses for patients experiencing ischemic stroke. Hypoxic preconditioning enhances the regenerative properties of bone marrow mesenchymal stem cells (BMSCs). Rabep2 (RAB GTPase binding effector protein 2) is a key protein in collateral remodeling. We investigated whether BMSCs and hypoxia-preconditioned BMSCs (H-BMSCs) augment collateral circulation poststroke, particularly through Rabep2 regulation.
METHODS
BMSCs or H-BMSCs (1×10) were delivered intranasally in ischemic mice with distal middle cerebral artery occlusion at 6 hours poststroke. Two-photon microscopic imaging and vessel painting methods were used to analyze collateral remodeling. Blood flow, vascular density, infarct volume, and gait analysis were assessed to evaluate poststroke outcomes. Expressions of proangiogenic marker VEGF (vascular endothelial growth factor) and Rabep2 were determined by Western blotting. Western blot, EdU (5-ethynyl-2'-deoxyuridine) incorporation, and tube formation assays were conducted on cultured endothelial cells treated with BMSCs.
RESULTS
BMSCs were more effectively transplanted in the ischemic brain after hypoxic preconditioning. The ipsilateral collateral diameter was increased by BMSCs and strengthened by H-BMSCs (<0.05). BMSCs increased peri-infarct blood flow and vascular density and reduced infarct volume, gait deficits (<0.05), and furthermore by H-BMSCs (<0.05). VEGF and Rabep2 protein expression was increased by BMSCs (<0.05), which was enhanced by preconditioning (<0.01). Additionally, BMSCs increased Rabep2 expression, proliferation, and tube formation of endothelial cells in vitro (<0.05). H-BMSCs enhanced these effects (<0.05), which were annulled by Rabep2 knockdown.
CONCLUSIONS
BMSCs increased collateral circulation and improved poststroke outcomes, through the upregulation of Rabep2. These effects were enhanced by hypoxic preconditioning.
背景
充足的侧支循环可以显著改善缺血性脑卒中患者的预后。低氧预处理可增强骨髓间充质干细胞（BMSCs）的再生特性。Rabep2（RAB GTPase 结合效应蛋白 2）是侧支重塑的关键蛋白。我们研究了 BMSCs 和低氧预处理的 BMSCs（H-BMSCs）是否能增加脑卒中后的侧支循环，特别是通过 Rabep2 调节。
方法
在脑卒中后 6 小时，通过远端大脑中动脉闭塞，将 1×10 的 BMSCs 或 H-BMSCs 经鼻腔递送至缺血性小鼠体内。采用双光子显微镜成像和血管染色方法分析侧支循环重塑。通过血流测定、血管密度、梗死体积和步态分析评估脑卒中后的转归。采用 Western blot 法检测促血管生成标记物 VEGF（血管内皮生长因子）和 Rabep2 的表达。采用 Western blot、EdU（5-乙氧嘧啶-2'-脱氧尿苷）掺入和管形成实验，观察经 BMSCs 处理的培养内皮细胞的变化。
结果
低氧预处理后，BMSCs 在缺血性大脑中的移植效果更好。BMSCs 可增加同侧侧支直径，并增强 H-BMSCs 的作用（<0.05）。BMSCs 增加了梗死周围的血流和血管密度，减少了梗死体积和步态缺陷（<0.05），H-BMSCs 的作用更强（<0.05）。BMSCs 增加了 VEGF 和 Rabep2 蛋白的表达（<0.05），低氧预处理增强了这一作用（<0.01）。此外，BMSCs 增加了内皮细胞的 Rabep2 表达、增殖和管形成（<0.05）。H-BMSCs 增强了这些作用（<0.05），而 Rabep2 敲低则消除了这些作用。
结论
BMSCs 通过上调 Rabep2 增加侧支循环，改善脑卒中后的转归。低氧预处理增强了这些作用。
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