正丁基苯酞诱导脑梗死后轴突再生的机制研究

The feature most important for treatment of ischemic stroke is how to promote functional restoration. Many of the sensory, motor, and cognitive impairments caused by stroke eventually improve, suggesting that the brain has the ability to rewire itself to restore lost functionalities. The modification of neuronal connections may result from axonal sprouting, neurogenesis, or remodeling of dendritic arbors. A better understanding of neuronal plasticity in functional recovery after stroke will be crucial to the development of pharmacologic and rehabilitative therapies for both ischemic and traumatic brain injury. Dl-3-n-butylphthalide (NBP), first isolated from the seeds of celery, is now synthesized in china and found to exert protective effects against ischemic brain. Dr. CUI Li-ying and colleagues presented the results of a randomized, double-blind trial aiming at assessing the efficacy and safety of NBP for treating acute ischemic stroke. They found that the long-term outcome measured by the modified Rankin scale (mRS) at 90-day was better in NBP group than control group. Rate of favorable outcome (mRS 0 to 1) is 63.80% in NBP group, significantly higher than that in control group (45.51%). Our previous data also showed NBP treatment significatly improved functional recovery which companied by the increase of axonal growth factor GAP43. Hereby, we tested the hypothesis that the functional restoration induced by NBP treatment of stroke is associtated with the neural network remodeling, including synaptic plasticity and axon growth in the ischemic brain. In this project, the primary cortical neurons culture was used to test the effect and molecular mechanism of NBP on neurite outgrowth. We also assess the functional recovey, axonal sprouting, synaptical plasticity, functional activity of brain cortex after delayed treatment with NBP. Furhtermore, we explore the molecular mechanism by which delay-treatment with NBP promoted neural plasticity after stroke.

神经网络重构是脑损伤后神经功能恢复的结构基础，如何促进神经功能的恢复是脑梗死治疗的难点。临床研究发现正丁基苯酞（NBP）治疗可使脑梗死患者远期残障率下降63.91%。本实验室前期研究发现：通过干预手段促进脑梗死后神经网络重构可显著改善神经功能，并发现NBP治疗显著增加轴突生长因子GAP43的表达，促进神经功能恢复，具有促进轴突再生的趋势，因此我们猜想NBP诱导的神经功能恢复可能与轴突再生及神经网络重构有关。据此本研究项目拟建立局灶性脑梗死动物模型及皮层神经元培养，通过在体、体外基础实验，研究NBP延迟治疗是否促进脑梗死后神经功能恢复、是否增强皮层功能活动？NBP诱导的神经功能恢复是否与轴突再生、神经网络重构有关？其机制如何？以期为脑梗死临床二级预防治疗提供理论依据。

本研究通过建立脑梗死动物模型，研究脑梗死后不同时期启动丁苯酞治疗对卒中恢复期神经恢复的影响。研究并发现shh通路为调节皮层神经元神经突起生长的重要作用通路，shh通过调节BDNF蛋白的活动促进神经突起的生长。氧化应激条件下，shh通路通过保护皮层神经元线粒体的形态和功能减轻神经元的损伤，促进轴突的生长。丁苯酞延迟治疗促进脑梗死后恢复期神经功能修复。发现丁苯酞促进脑梗死后轴突生长、突触再生等网络重构可能是促进梗死后神经功能恢复的重要作用机制。Shh通路可能为丁苯酞促进脑梗死后神经功能恢复的重要信号通路。