丰富环境辅以Rho激酶抑制剂对脑缺血白质纤维重建作用的研究

Remodeling neural networks, the premise of recovery from stroke, need orderly growth of sufficient white matter. Though Rho kinase inhibitor can promote the growth of white matter, it is still unclear how to orderly engage newly-born white matter into neural networks and to compensate functional deficit. Enriched environment (EE) has long been proved as an effective treatment to brain injury. Evidences showed that EE shaped the mode of white matter in normal rats. Our previous study also found that EE can remodel functional regions of cortex and facilitate recovery from brain ischemia. We deduced that cortical reconstructions might be accompanied with reshaping white matter in subcortical area. Therefore, we, in this study, will focus on the growth and modeling of white matter in post-ischemic mice. We planned to evaluate motor, sensory and cognitive function in mice, analyze the reshaping mode of white matter by neural tracing technique and immunohistochemistry, and test the function of remodeling white matter by electrophysiology, laser speckle imaging and light genetic techniques. Based on these tests, we try to demonstrate how EE orderly shape the newly-born white matter induced by Rho kinase inhibitor and merge them into integration, to provide a reference of translational medicine for the combination therapy of drug and rehabilitation, and a new evidence for the rehabilitation theory of post-stroke compensation.

神经网络重建是脑卒中功能恢复的前提，而足够的白质数量与有序塑造是神经网络代偿性重建的基础。Rho激酶抑制剂可促进白质生长，但如何将新生的白质有序地整合到神经网络中，发挥其代偿功能仍不清楚。丰富环境是一种脑损伤后有效康复干预手段，有研究发现丰富环境对正常大鼠白质具有塑造作用。我们前期研究证明，丰富环境可促进皮层功能重建，实现脑缺血后肢体功能的恢复，而皮层功能区的重建，可能存在皮层下相应白质纤维的重塑。因此本课题拟将脑缺血后的白质生长和塑造作为切入点，在功能层面评定小鼠肢体运动、感觉和认知功能的恢复情况；应用神经示踪技术和免疫组化技术检测白质结构的重建方式；应用电生理、激光散斑和光遗传学技术确定白质功能的重建效果。从而阐明丰富环境如何将Rho激酶抑制剂所促进的新生白质有机地塑造和整合，为脑卒中后药物结合康复训练的综合治疗方案提供转化医学层面参考，也为完善脑卒中康复的功能代偿理论提供新依据。

脑卒中发生后，脑白质的损伤尤为严重，白质的保护与结构重建成为脑卒中功能恢复的关键点。Rho/Rho相关蛋白激酶(Rho/Rho-associated kinase,Rho/ROCK)信号通路广泛参与中枢神经细胞生长、分化等生命体活动。法舒地尔是临床上惟一可用的ROCK抑制剂，它能保护神经细胞、促进轴突再生。我们前期研究证明，丰富环境（enriched environment, EE）可促进皮层功能重建，实现脑缺血后肢体功能的恢复。因此本课题以脑缺血损伤后白质结构和功能重建为切入点，探讨EE辅以ROCK抑制剂对脑缺血白质重塑的作用。首先，我们在分子层面上验证了法舒地尔通过抑制Rho/ROCK通路介导白质纤维生长；运用顺行神经示踪技术、免疫组化技术在白质结构层面观察到皮质脊髓束的轴突再生。进而应用光遗传学技术发现EE所介导的卒中后运动功能恢复，依赖于梗死对侧小脑深部核团的激活。应用激光散斑技术发现EE可以增强患侧桶状皮质中胡须刺激对脑血流的影响；应用电生理技术发现EE和法舒地尔可以有效地恢复海马CA1脑区的长时程增强（long-term potentiation，LTP）。最后，通过评定小鼠肢体运动功能、感觉功能和认知功能的恢复情况，观察其恢复程度与白质重塑的相关性，阐明EE对脑缺血后新生白质纤维在神经网络中的功能整合模式的影响。本研究为脑卒中后药物结合康复训练的综合治疗方案提供转化医学层面参考，也为完善脑卒中康复的功能代偿理论提供新依据。