缺氧诱导因子-1α抑制剂对大鼠局部脑缺血再灌注损伤的影响

目的研究大鼠局部脑缺血再灌注损伤时,缺氧诱导因子-1α(HIF-1α)抑制剂2-甲氧雌二醇(2ME2)对损伤脑组织的影响。方法雄性SD大鼠60只随机分为假手术组、大脑中动脉阻塞再灌注组(MCAO组)、假性治疗组(DMSO组)、2ME2治疗组(2ME2组)。治疗组在术后1h腹腔注射相应剂量药物。观察各组大鼠神经行为学缺陷;再灌注7d,TTC染色观察脑梗死体积变化;再灌注24h,Western blotting检测HIF-1α及其下游基因的表达变化;制备脑组织切片分别作Nissl染色、免疫组织化学染色及原位缺口末端标记(TUNEL)。结果2ME2组神经功能较MCAO及DMSO组有明显改善(P<0.05),同时,2ME2组梗死面积明显减小(P<0.05)。Western blotting结果显示,HIF-1α的表达经2ME2治疗后降低,其下游基因VEGF、BNIP3及Caspase-3的表达有同样的变化。Nissl染色可见2ME2治疗组皮质神经元结构较清晰,胞体肿胀、核固缩、核溶解程度较模型组及假性治疗组明显减轻,淡染区域减小;免疫组织化学法观察到2ME2组HIF-1α、Caspase-3、BNIP3、VEGF及TUNEL标记的阳性细胞数明显减少(P<0.05)。结论2ME2可能通过降低HIF-1α水平并下调其下游的BNIP3和VEGF的表达,降低血脑屏障的通透性并减少凋亡因子Caspase-3的作用,发挥神经元的保护作用。

THE EFFECT OF HIF-1α INHIBITOR ON THE INJURY INDUCED BY FOCAL CEREBRAL ISCHEMIA AND REPERFUSION IN RATS

Objective To investigate the effect of hypoxia inducible factor-1α (HIF-1α) inhibitor(2ME2) on the injury induced by focal cerebral ischemia. Methods Male SD rats were randomly divided into four groups: Control (sham surgery), Middle Cerebral Artery Occlusion and Reperfusion(MCAO), MCAO treated with vehicle(DMSO), MCAO treated with 2ME2. 2ME2 was injected intraperitoneally 1 hour after operation. The neurological deficits were observed in different groups. Rats were sacrificed 7 days later for TTC staining and 24 hours later for Western blotting, Nissl staining, immunohistochemical and TUNEL studies. Results 2ME2 improved neurological deficits(P<0.05), reduced the infarct area (P<0.05), inhibited the neuronal deformation shown by Nissl staining and reduced the expression of HIF-1α, activated Caspase-3, BNIP3 and VEGF detected by Western blotting and immunohistochemical staining.Conclusion 2ME2 is a powerful agent to protect the brain from cerebral ischemic injury by inhibiting HIF-1α activity, attenuating the superfluous expression of VEGF which results in the protection of Blood_Brain_Barrier (BBB) permeability, supp