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为了研究大鼠局灶性脑缺血再灌注损伤(CIRI)后血脑屏障(BBB)通透性的改变,观察5-脂氧酶(5-LO)、白三烯(LTs)、核因子-κB(NF-κB)、基质金属蛋白酶-9(MMP-9)的表达变化,探讨5-LO通路活化参与BBB破坏的可能机制,本实验采用线栓法制备大鼠大脑中动脉闭塞2h/再灌注24h模型。伊文氏蓝示踪剂检测BBB的通透性;RT-PCR检测损伤侧脑组织5-LO mRNA、半胱氨酰白三烯受体1(CysLTR1)mRNA的表达;ELISA检测血清LTB4的含量;免疫组织化学法检测损伤侧脑组织5-LO、NF-κB、MMP-9蛋白的表达情况。结果显示:局灶性脑缺血2h/再灌注24h后,大鼠BBB的通透性明显增高,5-LO mRNA、CysLTR1 mRNA的表达以及血清LTB4的含量均增高;5-LO、NF-κB、MMP-9蛋白在脑组织内的表达亦显著增多。本研究结果提示,CIRI后5-LO通路活化可经CysLTR1、LTB4、NF-κB、MMP-9介导BBB破坏,继而引发级联反应,加重脑损伤。
To investigate the changes of permeability of the blood-brain barrier (BBB) after focal cerebral ischemia-reperfusion injury (CIRI) in rats, the effects of 5-lipoxygenase (5-LO), leukotrienes (LTs) (NF-κB) and matrix metalloproteinase-9 (MMP-9) in rat brain to explore the possible mechanism of activation of 5-LO pathway involved in BBB destruction.In this study, middle cerebral artery occlusion was induced by thread occlusion for 2h / 24h reperfusion model. The permeability of BBB was detected by Evans blue tracer. The expression of 5-LO mRNA and cysLTR1 mRNA was detected by RT-PCR. The content of serum LTB4 was detected by ELISA. Immunohistochemistry was used to detect the expression of 5-LO, NF-κB and MMP-9 in injured side of brain. The results showed that the permeability of BBB increased obviously, the expression of 5-LO mRNA and CysLTR1 mRNA and the content of serum LTB4 increased after focal cerebral ischemia 2h / reperfusion 24h. The expressions of 5-LO and NF-κB , MMP-9 protein expression in brain tissue also increased significantly. Our results suggest that activation of 5-LO pathway after CIRI can induce BBB destruction via CysLTR1, LTB4, NF-κB and MMP-9, which in turn triggers a cascade reaction that aggravates brain injury.