局灶性脑缺血再灌注中c-Fos,胶质纤维酸性蛋白的表达和神经保护

Expressions of c-Fos and glial fibrillary acidic protein following focal cerebral ischemia reperfusion and their neuroprotection

目的:研究c-Fos和胶质纤维酸性蛋白(glialfibrillaryacidicprotein,GFAP)在局灶性脑缺血再灌注中的表达,尼莫地平脑保护作用的时机。方法:采用线栓法大脑中动脉闭塞90min加双侧颈总动脉结扎60min造模,18只SD大鼠随机等分为6组:对照组,I-R组,预防组,缺血治疗组,I-R治疗组,再灌注后治疗组。尼莫地平颈内动脉给药,再灌注后24h行脑功能障碍评分,再灌注72h处死测量脑组织梗死体积,并行苏木精-伊红染色,c-Fos,GFAP免疫组化染色。另选18只动物,I-R组9只和I-R治疗组9只各再分为再灌注后2,24和48h,行苏木精-伊红染色,c-Fos,GFAP免疫组化染色。结果:苏木精-伊红染色示预防组,I-R治疗组,再灌注后治疗组较之I-R组缺血半暗区神经元损伤明显减轻。再灌24h后神经功能障碍评分为:缺血治疗组(2.3±0.8)分≥I-R组(2.2±1.0)分>再灌注后治疗组(1.8±0.6)分>预防组(1.5±1.2)分>I-R治疗组(1.3±0.5)分>对照组(0.8±1.1)分,治疗组中除缺血治疗组外均较I-R组梗死体积小,但较对照组大,差异有统计学意义。治疗组皮质缺血半暗带,海马CA1区GFAP阳性细胞数均较I-R组少(P<0.05),但齿状回减少程度较轻;给药后皮质缺血半暗带以及海马各区c-Fos阳性细胞数明显减少。GFAP在再灌注2h大量表达,48h达高峰,且反应性星型胶质细胞居多,72h持续?

AIM:To investigate the expressions of c Fos and glial fibrillary acidic protein(GFAP) after focal cerebral ischemia reperfusion(I R) and the suitable neuroprotective opportunities of nimodipine. METHODS:Model was established with middle cerebral artery occlusion for 90 minutes and suture occlusion with bilateral common carotid artery ligation for 60 minutes.Eighteen SD rats were divided into 6 groups randomly and equally(n=3):control group,I R group,prevention group,ischemia treatment group,I R treatment group and post-reperfusion treatment group.Nimodipine was injected by an intracarotid route.The disordered brain function and the brain infarct volumes were evaluated at 24 hours and 72 hours after the reperfusion respectively.Hemotoxylin and eosin staining(HE staining),c Fos and GFAP immonohistochemiscal staining were performed simultaneously.Another 18 animal models were equally divided into two groups,I R and I R treatment groups,each group with 3 subgroups:2 hour group(A1 group),24 hour group(A2 group) and 48 hour group(A3 group) after reperfusion,and HE staining, c Fos and GFAP immonohistochemiscal staining were performed. RESULTS:HE staining showed penumbra neuron damages were alleviated significantly in prevention group,I R treatment group and post reperfusion treatment group as compared with those of I R group.After 24 hours of reperfusion,the scores of neurological dysfuctions took turns as follows: 2.3±0.8 for ischemia treatment group ≥2.2±1.0 for I R group >1.8±0.6 for postreperfusion treatment group >1.5±1.2 for prevention group >1.3±0.5 for I R treatment group >0.8±1.1 for control group.Infarct volume of treatment groups except that of ischemia treatment group decreased significantly as compared with that of I R group,while increased as compared with that of control group.There were statistical differences.GFAP positive cells in cortex penumbra and CA1 were less than those of I R group(P< 0.05),but there were gentle reductions of the number in dentate gyrus. The number of c Fos positive cells in the same regions decreased significantly after treatment. Following reperfusion,GFAP clearly expressed at 2 hours, peaked at 48 hours and persisted at 72 hours when the reactive astrocytes were the most,while c Fos responsed strongly at 2 hours,still expressed massively at 24 hours,decreased significantly at 48 hours,and expressed in small quantity at 72 hours. CONCLUSION:Preventive and earlier reperfusion intracarotid nimodipine infusion has better therapeutic efficacy on focal cerebral I R.Reactive glial cells play important roles in the neuron survivals after ischemia reperfusion. Gene c Fos may take part in the signal transduction of cerebral ischemia injury.