脑缺血再灌注大鼠学习记忆能力和海马组织CREB、C/EBP的DNA结合活性改变

Change of learning and memory ability and DNA-binding activity of CREB and C /EBP in hippocampus of vascular dementia rats

目的观察脑缺血再灌注大鼠学习记忆能力和海马组织环磷酸腺苷反应(cAMP)元件结合蛋白(CREB)及CCAAT/增强子结合蛋白(C/EBP)的DNA结合活性改变。方法采用4血管法制备大鼠缺血再灌注损伤模型,用水迷宫检测大鼠学习记忆能力,HE染色观察海马CA1区神经元形态改变,凝胶电泳迁移率改变分析法(EMSA)测定CREB和C/EBP的DNA结合活性。结果水迷宫检测:与假手术组术比较,模型组大鼠逃逸潜伏期明显延长(P<0.05),跨越平台次数明显减少(P<0.05)。HE染色:假手术组大鼠海马CA1区神经元排列整齐、均匀,细胞结构完整;模型组大鼠海马CA1区部分神经元正常结构消失,胞核区域浓染,出现凝固性坏死及细胞脱失,海马CA1区正常神经细胞数目较假手术组明显减少(P<0.05)。EMSA检测:模型组大鼠海马组织CREB和C/EBP的DNA结合活性均较假手术组显著降低(P<0.01)。结论 CREB和C/EBP的DNA结合活性下降可能参与了脑缺血再灌注损伤引起的神经元损伤和学习记忆能力下降。

Objective To observe the DNA-binding activity change of CREB and C/EBP in hippocampus tissue of after ischemia/ reperfusion( I / R) in rats and explore the mechanism of injuries subjected to cerebral I / R. Methods Vscular dementia( VD) rat models were prepared by four-vessel occlusion. The Morris maze was used to detect the changes of spatial learning and memory,while HE straining was used to observe the change of pathological characteristics in hippocampus CA1 area,and Electrophoretic Mobility Shift Assay( EMSA) was used to observe DNA-binding activity changes of cAMP response element binding protein( CREB) and CCAAT / enhancer binding protein( C/EBP) in hippocampus tissue. Results The Morris maze showed: compared with sham-operated group's escape latency was significantly longer( P<0. 05) and the times of cross-platform was reduced( P<0. 05) noticeably in I / R model group. HE results: the normal form of organizations,neurons in hippocampal CA1 area were uniform and arranged neatly,meanwhile the cell structure was integrity in sham-operated group. In VD rat model group,neurons were scattered and boundaries were unclear,nuclei region stained,coagulation necrosis appeared, obviously cells depigmentation. The number of hippocampal normal neurons in I / R model group was significantly reduced( P<0. 05) compared with the sham-operated group. EMSA discovered the DNA-binding activity of CREB in rat hippocampus tissue was significantly lower in I / R model group than that in sham-operated group. Conclusions The decline in DNA-binding activity of CREB and C / EBP in hippocampus tissue may be involved in the descent of learning and memory function and neuron injuries in rat after I / R.