缺血再灌注损伤大鼠脑组织脑红蛋白表达的变化

Changes of Neuroglobin Expression Following Cerebral Ischemic Reperfusion Injury in Rats

目的探讨脑缺血再灌注损伤大鼠脑红蛋白(NGB)表达的变化与再灌注损伤时间的关系。方法建立大鼠脑缺血再灌注损伤动物模型,测定缺血再灌注损伤1h、4h、8h、16h、32h、64h、128h大脑皮质NGB表达的变化,对实验动物进行神经行为功能测试,并与假手术对照组进行比较。结果缺血再灌注损伤组与假手术组各时点比较,大脑皮层NGB阳性神经元呈现先上升后下降的趋势;而脑非缺氧性损伤侧神经元NGB阳性表达不随时间变化而改变。缺血再灌注损伤组缺血侧大脑皮层呈现延缓性脑梗死过程,各时间点组织切片显示缺血中心部位(纹状体和皮层外侧区)神经元损伤发生在缺血后8h,随着缺血时间的延长逐渐向半暗带区扩展,脑梗死灶逐渐扩大。再灌注1～128h,缺血侧缺血半暗带皮层NGB阳性神经元呈现先上升后下降的趋势,而非缺血侧对称区域皮层NGB阳性表达不随时间变化。缺血再灌注损伤后1h,缺血侧扣带皮层NGB阳性神经元数量无明显改变;再灌注损伤8～64h,在同一只大鼠脑组织缺血侧皮层NGB的表达与对侧NGB的表达存在显著差异:损伤8h,NGB阳性神经元数量开始增加(A=0.04±0.004P<0.05),损伤16h,NGB阳性神经元数量显著增加(A=0.06±0.003P<0.01),损伤32h达高峰(A=0.07±0.006P<0.05)。损伤64h,NGB阳性神经元数量显著减少(A=0.03±0.007P<0.05);损伤128h,缺血侧与非缺血侧扣带皮层NGB阳性神经元数量基本相当(A=0.04±0.006P>0.05),而脑非缺血侧脑组织NGB阳性细胞表达变化不大,各组间差异比较无统计学意义(P>0.05)。结论脑缺血再灌注损伤大鼠神经元NGB的表达变化呈现时间规律性,提示NGB对缺氧缺血性脑损伤有保护作用。

Objective To investigate the changes of neuroglobin （NGB） expression in rats following cerebral ischemic reperfusion injury. Methods Sprague - Damley male rats were subjected to 90 min of ischemia induced by middle cerebral artery occlusion with a filament insert, and changes of NGB expression in the cortex of cerebrum after ischemic reperfusion injury of at different periods were observed ： 1 h, 4 h,8 h, 16 h,32 h,64 h,128 h,which were compared with those of the sham operated rats in control group, hnmunohistochemical method was used to observe the changes of NGB staining in cerebral ischemic penumbra. Results The NGB positive neurons in the cerebral cortex rose first and then fell in both ischemic reperfusion injury group and non - operation group at different periods ; while in non - ischemic side, the NGB positive neuron expression did not vary with the periods of time. Cerebral infarction process at cerebral cortex of ischemic reperfusion injury group manifested at different times showed：after 8 hours of neurons ischemic injury in stratum and cortical area, cerebral infarction was expanded following ischemia times. After ischemic reperfusion injury 1 - 128 hours, the first rise and down after of ischemic cerebral cortex NGB positive neurons ; there was no change in NGB positive neurons with time at cerebral non - ischemic area. After ischemic reperfusion injury 1 hour, no difference in NGB positive neurons were observed in the ischemic area of gyrus cinguli cerebral;after ischemic reperfusion injury 8 - 64 hours, there was different NGB express in cerebral cortex of ischemic and no - ischemic cerebral： After injury 8 hours, NGB positive neurons rose（A =0.04 ±0.004 P 〈0.05） , after injury 16 hours,NGB positive neurons went up markedly （A =0.0.6±0.003 P 〈0.01 ） , after injury 32 hours, there was most of NGB positive neurons rising （A = 0.07 ± 0. 006 P 〈 0.05 ） , after injury 64 hours, NGB positive neurons were down sharply （ A = 0.03 ± 0. 007 P 〈 0.05 ） ; after injury 128 hours, NGB positive neurons of gyms cinguli were the same for both ischemie and non - ischemic （A = 0.04 ± 0. 006 P 〉 0.05 ）. These groups had no difference NGB positive neurons expressions in rats of non - isehemia （ P 〉 0.05 ）. Conclusion NGB may play an important role in the adaptive protection process of ischemic reperfusion injury.