蓝布正提取物改善脑缺血后神经功能损伤作用及机制研究

Study on the effect and mechanism of Geum aleppicum Jacq extract on improving neurological dysfunction after cerebral ischemia

关键词:  缺血性脑卒中  蓝布正提取物  运动功能损伤  血管生成

Key words:  ischemic stroke  Geum aleppicum Jacq extract  neurological dysfunction  angiogenesis

摘要:

目的 研究蓝布正提取物LBZ-55对光栓所致小鼠脑缺血后运动功能损伤的影响,并探讨其潜在作用机制。方法 利用小鼠光化学栓塞法(photothrombosis model, PT)建立局灶性急性脑缺血模型,术后连续14 d灌胃给予小鼠LBZ-55,每隔1 d采用圆筒和网格实验评价小鼠运动功能,甲苯胺蓝染色检测脑梗死体积；采用激光散斑成像监测脑血流量的变化,并于术后7 d采用免疫组织化学法检测梗死灶周围血管数量；用伊文思蓝染色检测血脑屏障的渗漏；采用氧糖剥夺模拟体外脑缺血,检测bEnd.3细胞的迁移能力和成管能力。结果 PT造模后小鼠连续14 d给予LBZ-55可显著降低其错步率和不对称指数,但未减少缺血侧脑梗死体积,提示LBZ-55改善脑缺血小鼠神经功能损伤,其作用可能与直接神经保护作用无关；连续7d给予LBZ-55显著增加小鼠患侧脑血流量,梗死脑组织周围的血管密度,梗死及周围皮层中VEGFA蛋白表达显著增高；血脑屏障渗漏减轻,claudin-5,ZO-1蛋白表达显著增多；LBZ-55可以促进氧糖剥夺后细胞的迁移能力,形成的小管数目和分支显著增多。结论 LBZ-55可以改善光栓诱导的小鼠脑缺血后神经功能,改善缺血区域脑血流及周围血管密度,显著增加缺血脑组织VEGFA蛋白表达,减轻血脑屏障损伤,该作用可能与促进脑缺血后血管生成机制有关。

Abstract:

OBJECTIVE To study the effect of Geum aleppicum Jacq extract LBZ-55 on motor function injury after cerebral ischemia in mice induced by photothrombosis, and to explore its potential mechanism. METHODS The model of focal acute cerebral ischemia was established by photothrombosis model in mice. LBZ-55 was administered intragastrically for 14 days after operation. The motor function of mice was evaluated by cylinder and grid experiments every other day, and the volume of cerebral infarction was detected by toluidine blue staining. The changes of cerebral blood flow were monitored by laser speckle imaging, and the number of blood vessels around the infarct was detected by immunohistochemistry on the 7 th day after operation. The leakage of blood-brain barrier was detected by Evans blue staining. Oxygen glucose deprivation was used to simulate cerebral ischemia in vitro,and the migration ability and tube formation ability of bEnd.3 cells were detected. RESULTS LBZ-55 administration for 14 consecutive days after PT modeling significantly reduced the step-out rate and asymmetry index, but did not reduce the volume of cerebral infarction on the ischemic side, suggesting that LBZ-55 improved neurological damage in mice with cerebral ischemia, and its effect may not be related to direct neuroprotective effects ; continuous administration of LBZ-55 for 7 days significantly increased the cerebral blood flow of the affected side of the mice, the vascular density around the infarcted brain tissue, and the expression of VEGFA protein in the infarcted and surrounding cortex. The leakage of blood-brain barrier was reduced, and the expression of claudin-5 and ZO-1 protein was significantly increased. LBZ-55 can promote the migration ability of cells after oxygen-glucose deprivation, and the number and branches of tubules formed are significantly increased. CONCLUSION LBZ-55 can improve the neurological function of mice after cerebral ischemia induced by photothrombosis, improve the cerebral blood flow in ischemic area and the density of surrounding blood vessels, significantly increase the expression of VEGFA protein in ischemic brain tissue, and reduce the damage of blood-brain barrier. This effect may be related to the mechanism of promoting angiogenesis after cerebral ischemia.