全脑缺血再灌注后磷酸化ERK蛋白的表达及应用PD98059后对其表达的影响

The Expression of ERK After Global Cerebral is Chemia/Reperfusion and Effect of PD98059 on it

目的:全脑缺血再灌注后磷酸化ERK(p-ERK)蛋白的表达与细胞凋亡的关系及应用ERK通路抑制剂PD98059后对其表达的影响,以探讨ERK通路在脑缺血再灌注损伤中的作用。方法:健康雄性SD大鼠90只,随机分为三组:缺血再灌注组(IR,n=30):采用4-VO法建立全脑缺血再灌注模型,6min缺血后给予再灌注。假手术组(PO,n=30):只暴露血管而不夹闭,PD98059组(PD,n=30):缺血前20min经尾静脉注入PD98059,另两组予以生理盐水行干预。各组动物于再灌注后2h、6h、12h、24h、48h、72h处死,将脑组织切片进行HE染色、免疫组化染色和TUNEL检测。结果:HE染色结果PD组变化显著,细胞破坏更严重,于各时间点细胞形态变化较IR组更为明显;IR组p-ERK在海马CA1区锥体细胞未见表达,CA3区于再灌注后2h有弱表达,于再灌注6h达高峰后逐渐下降,至再灌注后48h未见表达,PD组表达弱于IR组(P<0.05);IR组中CA1区2h即有散在的凋亡细胞,24h～48h达峰值,PD组各时点于各区凋亡细胞计数多于IR组(P<0.05)。结论:ERK信号转导通路在脑缺血再灌注中参与了缺血后神经元的保护,发挥抗凋亡作用。

Objective To study the relationship between expression of p-ERK with cell apoptosis and influence of PD98059 pretreatment on the expression and cell apoptosis. Methods 90 healthy male SD Rats were divided into 3 groups randomly. Ischemia/reperfusion group（IR group, n=30）： global cerebral ischemia/reperfusion model was produced by 4-VO method. Reperfusion were performed after 6 min. Sham group （PO group, n=30）： blood vessel were just exposed but not occlusion. PD98059 group （PD,n=30）;inject PD98059 from rat tail＇ s vein before cerebral ischemia,the other groups inject salt water. All animals were executed at 2 h, 6 h, 12 h, 24 h, 48 h, and 72 h. HE staining ,TUNEL and Immunohistochemical staining of brain tissue section were performed. Results HE staining showed the change in group PD was the most severous. There was no p-ERK expressed in CA1 oflR group.In CA3 increased after that time and peaked at 6h, then decreased .The positive straning were localized in nucelus.and the nucleus is more obviously,until 48h there was no expression. Expression in PDgroup were weaker than that in IR group. TUNEL detection in IR group showed that the number of positive cell peaked at 24 h-48 h after global cerebral ischemia/reperfusion in CA1 of hippocampus. The number of that in group PD was the most. Conclusion ERK expressed in both CA1 and CA3 ofhippocampus after cerebral ischemia/reperfusion, which showed different intensity with different time. ERK gived play to pretect neurons and righted against apoptosis.