脑卒中早期运动调控IL-18/NF-κB/MMPs通路的机制研究

The neurological functions of rats can be significantly improved with exercise initiated early after ischemia stroke. However, their underlying mechanisms are poorly understood. Acute inflammatory response and brain edema after cerebral ischemia are mainly because of the damage of blood brain barrier (BBB). Therefore, protecting the function of BBB might be the important mechanism of early exercise promoting the recovery of brain functions. Our earlier researches have shown that early exercise for stroke could significantly alleviate the neurological inflammatory reaction, reduce permeability of BBB and attenuate brain edema. For the underlying mechanisms, we hypothesized that early exercise might down-regulate IL-18 expression, inhibiting the NF-κB-MMPs signal pathway. IL-18 induced a number of MMP genes, particularly MMP-9, maintaining the balance extracellular matrix (ECM) degradation and sedimentary and protecting the BBB. To verify the hypothesis, our researches focus on the influence on the integrity of BBB and the expression of IL-18, NF-κB and MMPs through exercise after stroke. We test the enzymatic activity of MMP-9 in situ zymography. Meanwhile, we culture blood brain barrier model in vitro, simulate of the cerebral blood flow with deficient glucose and hypoxiathrough，combine with various molecular blockers to detect the influence of the integrity of BBB and the edema and apoptosis of endothelial cells via IL-18/NF-κB /MMPs. Finally, the molecular mechanism for neuroprotection of blood brain barrier by early exercise can be demonstrated in vivo and vitro verification research.

脑卒中早期运动可保护血脑屏障，促进神经功能恢复，但对其机制研究甚少。血脑屏障破坏是脑缺血早期神经炎性反应和脑水肿的主要原因，保护血脑屏障功能可能是早期运动训练促进脑功能恢复的重要机制。我们前期研究表明脑卒中早期运动能显著减轻神经炎性反应、降低血脑屏障通透性和脑水肿程度。对其分子机制，我们推测脑卒中早期运动下调IL-18表达，从而抑制NF-κB-MMPs信号通路，调控MMPs基因表达，维持胞外基质沉积和降解的动态平衡，保护血脑屏障功能。为验证这一假说，通过研究脑卒中后运动训练对IL-18、NF-κB和MMPs表达及血脑屏障完整性的影响，采用原位酶谱技术检测MMPs活性。同时，建立体外血脑屏障模型，进行缺糖缺氧处理模拟脑缺血，并结合分子阻断剂验证IL-18/NF-κB-MMPs信号通路在缺血引起的血脑屏障破坏及内皮细胞水肿和凋亡中的作用。通过体内外的研究阐明早期运动对血脑屏障保护的分子机制。

脑卒中早期运动保护血脑屏障促进神经功能恢复的机制尚不明确。在本课题的研究中，我们发现早期运动能显著减轻炎症反应和水肿，下调IL-18表达，抑制NF-kb/MMP9通路，调控MMP9基质金属酶的表达，维持大脑内细胞外基质沉积和降解平衡，保护血脑屏障不被进一步破坏。我们应用了多种技术建立体外血脑屏障模型，体外缺血缺氧模型、分子阻断技术，并在动物体内大脑中动脉栓塞模型确认研究结果，发现早期运动不仅能保护血脑屏障，降低内皮细胞水肿和凋亡。并结合最新研究热点，我们关注到脑卒中后运动康复神经功能重建是一系列基因重组的过程，我们已经通过microRNA芯片技术，筛选脑缺血后早期运动康复干预的差异性表达microRNA，并通过靶基因预测及功能学验证，从整体上给出脑缺血后早期运动干预保护血脑屏障、促进脑功能重建的可能分子机制及相关通路。