短暂缺氧致新生大鼠海马内β-连环素、神经源性分化因子1和胰岛素受体表达动态改变

Transient hypoxia causes dynamic changes in the expression of β-catenin,neurogenic differentiation factor 1 and insulin receptor in the hippocampus of neonatal rats

目的探讨短暂缺氧对新生大鼠海马β-连环素(β-catenin)、神经源性分化因子1(NeuroD1)、胰岛素受体(insulin receptor)表达的影响。方法将3日龄SD大鼠置于8%O_(2)+92%N_(2)的混合气体中2h,采用尼氏染色及透射电镜观察海马结构病理变化;于缺氧后2h、4h、24h断头取脑,免疫荧光染色法、实时荧光定量PCR技术检测海马结构β-catenin、NeuroD1、insulin receptor表达的变化。结果缺氧后大鼠海马结构发生细胞排列松散、细胞间隙增宽、神经元轻度肿胀等超微结构以及细胞形态的改变。与对照组相比,免疫荧光染色显示:缺氧后2h,3种蛋白的免疫荧光强度无明显差别;缺氧后4h,3种蛋白免疫荧光强度出现增高;缺氧后24h,三种蛋白免疫荧光强度均增高。实时荧光定量PCR显示:与对照组相比,大鼠缺氧后2h,三组目的基因表达量无统计学差异;缺氧后4h,β-catenin基因表达量降低,NeuroD1和insulin receptor基因表达量增高;缺氧后24h,β-catenin和insulin receptor基因表达量无统计学差异,但NeuroD1基因表达量持续增高。结论采用3日龄SD大鼠置于8%O_(2)+92%N_(2)的混合气体中2h,可建立缺氧性脑损伤模型,缺氧可能通过上调通路关键因子激活Wnt/β-catenin/NeuroD1途径对大鼠海马β-catenin、NeuroD1和insulin receptor的表达产生影响。

Objective To investigate the effect of transient hypoxia on the expression of β-Catenin,NeuroD1 and insulin receptor in the hippocampus of 3-day-old SD rats.Methods SD rats of 3 days old were exposed to the mixture of 8% O_(2) + 92% N_(2) for 2 hours.The pathological changes of the hippocampus were observed by Nissl staining and transmission electron microscope.The brains were decapitated at 2 h,4 h and 24 h after hypoxia.Immunofluorescence and real-time fluorescence quantitative PCR were used to detect the expression of β-catenin,NeuroD1 and insulin receptor in the hippocampus.Results The ultrastructural and morphological changes of hippocampal cells,such as the loose arrangement of cells,widened intercellular space,and the slight swelling of neurons,occurred after hypoxia.Compared with the control group,immunofluorescence staining showed no significant difference in the immunofluorescence intensity of the three target proteins at 2 h after hypoxia,but they increased at 4 h and 24 h after hypoxia.Compared with the control group,real-time quantitative PCR showed no significant difference in the mNRA expression of three target genes at 2 h after hypoxia;at 4 h after hypoxia,the expression of β-catenin decreased,while the expression of NeuroD1 and insulin receptor increased;at24 h after hypoxia,there was no significant difference in the expression of β-catenin and insulin receptor,but the expression of NeuroD1 continued to increase.Conclusion The model of hypoxic brain injury can be established by exposing 3-day-old SD rats to 8% O2 + 92% N2 for 2 h.Hypoxia can affect the expression of β-catenin,NeuroD1 and insulin receptor in the rat hippocampus by up-regulating the Wnt/β-catenin/NeuroD1 pathway.[Abstract]Objective To investigate the effect of transient hypoxia on the expression of β-Catenin,NeuroD1 and insulin receptor in the hippocampus of 3-day-old SD rats.Methods SD rats of 3 days old were exposed to the mixture of 8% O_(2)+92% N_(2) for 2 hours.The pathological changes of the hippocampu s were observed by Nissl staining and transmission electron microscope.The brains were decapitated at 2 h,4 h and 24 h after hypoxia.Immunofluorescence and real-time fluorescence quantitative PCR were used to detect the expression of β-catenin,NeuroD1 and insulin receptor in the hippocampus.Results The ultrastructural and morphological changes of hippocampal cells,such as the loose arrangement of cells,widened intercellular space,and the slight swelling of neurons,occurred after hypoxia.Compared with the control group,immunofluorescence staining showed no significant difference in the immunofluorescence intensity of the three target proteins at 2 h after hypoxia,but they increased at 4 h and 24 h after hypoxia.Compared with the control group,real-time quantitative PCR showed no significant difference in the mNRA expression of three target genes at 2 h after hypoxia;at 4 h after hypoxia,the expression of β-catenin decreased,while the expression of NeuroD 1 and insulin receptor increased;at24 h after hypoxia,there was no significant difference in the expre ssion of β-catenin and insulin receptor,but the expre ssion of NeuroD 1 continued to increase.Conclusion The model of hypoxic brain injury can be established by exposing 3-day-old SD rats to 8% O2+92% N2 for 2 h.Hypoxia can affect the expression of β-catenin,NeuroD 1 and insulin receptor in the rat hippocampus by up-regulating the Wnt/β-catenin/NeuroD 1 pathway.