缺氧预处理对新生大鼠缺氧缺血性脑细胞凋亡的影响

Effect of hypoxia preconditioning on neuron apoptosis in the neonatal rats with hypoxic-ischemic brain damage

目的 :研究缺氧预处理对新生大鼠缺氧缺血性脑损伤时脑组织缺氧诱导因子 1α(HIF 1α)mRNA及脑细胞凋亡的影响。方法 :新生 7日龄SD大鼠随机分为空白对照组 (n =12 )、假手术组 (n =12 )、缺氧缺血组 (HIBD组 ,n =15 )和缺氧预处理后缺氧缺血组 (HPC组 ,n =2 1) ,缺氧预处理组在行HIBD模型前 2 4h吸 8%浓度氧 3h。各组大鼠均于 14日龄处死。观察大鼠脑组织神经病理学变化 ;采用末端脱氧核苷酸介导的X DUTP缺口末端标记法测定神经元凋亡的情况 ;采用定量逆转录多聚酶链反应 (RT PCR)法测定大鼠脑组织HIF 1αmRNA的表达。结果 :HPC组脑皮层神经细胞变性坏死较HIBD组减轻 ,HPC组大鼠脑组织HIF 1α基因的表达较HIBD组下降 ,HPC组脑细胞凋亡数目较HIBD组减少。结论 :缺氧预处理可保护新生大鼠缺氧缺血性脑损伤 ,减弱HIF 1αmRNA的表达 。

Objective To investigate the effect of hypoxia preconditioning (HPC) on the expression of hypoxia inducible factor 1α( HIF 1α)mRNA and neuron apoptosis in neonatal rats with cerebral hypoxia ischemia.Methods The 7 day old Sprague Dawley(SD) rats were randomly divided into 4 groups: control group ( n =12),sham operated group ( n =12), hypoxic ischemic brain damage (HIBD) group ( n =15),and hypoxia preconditioning (HPC) group ( n =21). Preconditioning was performed 24 h before hypoxic ischemic (HI) by placing rats in the hypoxic chamber of 8% oxygen for 3 hours. Rats of each gloup were executed on 14 th day. Neuropathologic changes were studied. Terminal deoxynucleotidyl transferase mediated biotinylated deoxyuridine triphosphate nickel end labeling was used to examine neuron apoptosis. Quantitative reverse transcription polymerase chain reaction (RT PCR) was used to examine the expression of HIF 1α mRNA at ipsilateral cerebral hemisphere.Results The degree of neuron damage, the expression of HIF 1αmRNA, and the number of neuron apoptosis decreased in the HPC group compared with those in the HIBD group.Conclusion HPC has protective effect on neonatal rats with cerebral hypoxia ischemia. HPC can significantly weaken the expression of HIF 1αmRNA and decrease neuron apoptosis.