Jin Yongming, Barnett Austin, Zhang Yifan, Yu Xin, Luo Yu
From the Department of Neurological Surgery (Y.J., A.B., Y.L.) and Department of Biomedical Engineering (Y.Z., X.Y.), Case Western Reserve University, Cleveland, OH.
Stroke. 2017 Jun;48(6):1636-1645. doi: 10.1161/STROKEAHA.117.016650. Epub 2017 May 9.
Because of the limitation in treatment window of the r-tPA (recombinant tissue-type plasminogen activator), the development of delayed treatment for stroke is needed. In this study, we examined the efficacy of delayed poststroke treatment (post 3-8 days) of the sonic hedgehog pathway agonist on functional recovery and the underlying mechanisms.
We evaluated functional recovery at 1 month after stroke using locomotion analysis and Barnes maze test for cognitive function. We used a genetically inducible neural stem cell-specific reporter mouse line (nestin-CreERT2-R26R-YFP) to label and track their proliferation, survival, and differentiation in ischemic brain. Brain tissue damage, angiogenesis, and cerebral blood flow recovery was evaluated using magnetic resonance imaging techniques and immunostaining.
Our results show that delayed treatment of sonic hedgehog pathway agonist in stroke mice results in enhanced functional recovery both in locomotor function and in cognitive function at 1 month after stroke. Furthermore, using the Nestincre-ERT2-YFP mice, we showed that poststroke sonic hedgehog pathway agonist treatment increased surviving newly born cells derived from both subventricular zone and subgranular zone neural stem cells, total surviving DCX+ (Doublecortin) neuroblast cells, and neurons (NeuN+/YFP+) in the ischemic brain. Sonic hedgehog pathway agonist treatment also improved the brain tissue repair in ischemic region supported by our T2-weighted magnetic resonance imaging, cerebral blood flow map by arterial spin labeling, and immunohistochemistry (α-smooth muscle actin and CD31 immunostaining).
These data confirm an important role for the hedgehog pathway in poststroke brain repair and functional recovery, suggesting a prolonged treatment window for potential treatment strategy to modulate sonic hedgehog pathway after stroke.
由于重组组织型纤溶酶原激活剂（r-tPA）治疗窗的限制，需要开发针对中风的延迟治疗方法。在本研究中，我们研究了中风后延迟治疗（3 - 8天）时，音猬因子通路激动剂对功能恢复的疗效及其潜在机制。
我们在中风后1个月使用运动分析和巴恩斯迷宫试验评估认知功能，以此来评估功能恢复情况。我们使用一种基因诱导的神经干细胞特异性报告小鼠品系（巢蛋白-CreERT2-R26R-YFP）来标记和追踪其在缺血性脑内的增殖、存活及分化情况。使用磁共振成像技术和免疫染色评估脑组织损伤、血管生成及脑血流恢复情况。
我们的结果表明，中风小鼠中延迟给予音猬因子通路激动剂治疗可使中风后1个月时的运动功能和认知功能均得到增强的功能恢复。此外，利用巢蛋白-Cre-ERT2-YFP小鼠，我们发现中风后给予音猬因子通路激动剂治疗可增加源自脑室下区和颗粒下区神经干细胞的存活新生细胞、总的存活双皮质素（DCX+）神经母细胞以及缺血性脑内的神经元（NeuN+/YFP+）。音猬因子通路激动剂治疗还改善了缺血区域的脑组织修复，这得到了我们的T2加权磁共振成像、动脉自旋标记脑血流图以及免疫组化（α-平滑肌肌动蛋白和CD31免疫染色）的支持。
这些数据证实了刺猬因子通路在中风后脑修复和功能恢复中的重要作用，提示中风后调节音猬因子通路的潜在治疗策略具有延长的治疗窗。
