c-fos mRNA在围产期缺血缺氧脑损伤后的表达特点

EXPRESSION OF c-fos mRNA FOLLOWING PERINATAL ISCHEMIC-HYPOXIA

为探讨围产期缺血缺氧脑损伤的发病机制，本实验对c-fos在脑缺血缺氧后的表达变化规律进行了研究。通过结扎Wistar孕鼠一侧子宫角血管的方法（未结扎侧子宫角作为对照），建立围产期缺血缺氧脑损伤动物模型。采用原位杂交方法观察了剖宫产后存活不同时间的大鼠大脑c-fosmRNA的表达，结果发现，缺血后即刻，大脑皮层和海马即出现c-fosmRNA的表达。随时间延长，表达量逐渐增加，至1h时，杂交信号最强，维持到2、4h后逐渐减弱。但到24h时.c-fosmRNA又出现第二次高表达，以后又逐渐减低，48h表达极微，3d后各组都未检出其表达。对照组仅在生后1h海马有较少量c-fosRNA的表达。结果表明，宫内缺血缺氧引起了即刻早期基因c-fosmRNA的表达增强，且具有一定规律性。c-fos的改变可能会引起其后续靶基因尤其是一些与细胞死亡相关基因的转录，从而引起脑组织的病理损害。

The regularity of immediate early gene (IEG, c-fos) mRNA expression was studied to investigate the pathogenesis of perinatal ischemic-hypoxia. We set up an animal model of perinatal ischemic-hypoxia with Wistar rat by ligating the uterine vessel of one pregnant horn. The other horn was not ligated and the fetuses were used as controls. Pups were delivered by cesarean section at the end of the ischemic-hypoxic (IH) insult and then the brain tissues were collected in differrent times. In situ hybridation was used to detect the expression of c-fos mRNA. our results showed that the expression of c-fos mRNA was shown immediately (0 minute) in hippocampus and cerebral cortex, increased as the time went on. peaked at 1 hour the high expression lasted 2 hours and subsided gradually after 4 hours. However. more intensive c-fos mRNA expression was found at 24 hours and then the expression disapeared at 72 hours. only a trace of hybrid signal could be found at 1 hour in hippocampus in the control group. These results indicated that immediate early gene c-fos could be induced by perinatal ischemic-hypoxia. The expression of c-fos mRNA might induce the transcription of its target genes, especially, some 'killer genes'. which would be harmful to the brain tissue.