新生鼠缺氧缺血性脑损伤时铁离子螯合剂对HIF-1α的调节作用

The regulation of deferoxamine on HIF-1α expression after hypoxia-ischemia brain damage in neonatal rats

目的探讨新生鼠缺氧缺血性脑损伤(HIBD)时铁离子螯合剂(DFO)对缺氧诱导因子1α(HIF-1α)的调节作用,以期寻找缺氧缺血性脑损伤的治疗策略。方法以生后10日龄SD大鼠为研究对象,制作HIBD动物模型,并经腹腔内注射DFO及生理盐水(NS)干预。应用Western blot分析检测HIF-1α蛋白表达,RT-PCR检测HIF-1αmRNA表达水平。结果缺氧缺血组HIF-1α蛋白4h即明显增多,8h达高峰,24h开始下降。NS干预组与缺氧缺血组有相同的变化。而DFO干预组则4h达高峰,8h及24h仍在较高水平,与缺氧缺血组比较,各时间点HIF-1α蛋白表达均增多,差异有统计学意义(P<0.05)。各组各损伤时间点HIF-1α蛋白表达与对照组比较均有增高(P<0.05)。缺氧缺血组与DFO干预组比较,各时间点HIF-1α mRNA表达均有增加。结论在新生鼠缺氧缺血性脑损伤时,DFO可上调HIF-1α的蛋白及mRNA表达,使HIF-1α蛋白表达高峰时间提前且持续时间延长。

Objective To study the role of deferoxamine （ DFO） on regulating hypoxia-inducible factor 1α （HIF-1α） expression after hypoxia-ischemia brain damage （HIBD） in neonatal rats,to explore the therapeutic strategy for HIBD.Methods Postnatal day 10 SD rats were divided into four groups： hypoxia-ischemia （HI） group,DFO- treated group,normal saline （NS） -treated group,and sham operation group.HIBD model was established by the ligation of right common carotid artery following the inhalation of nitrogen-oxygen mixtures containing 92% nitrogen and 8% oxygen.DFO-treated group and NS-treated group were treated by intraperitoneal injection of DFO or NS respectively.The brains were collected at 4 h,8 h,and 24 h after hypoxia.HIF-1α protein expression was detected by Western blot analysis,and HIF-1α mRNA expression was detected by using RT-PCR at each time point.Results The synthetic level of HIF-1α protein increased significantly at 4 h,peaked at 8 h,and decreased at 24 h after HI in HI group,as well as NS-treated group.However,in DFO-treated group HIF-1α protein was peaked at 4 h,maintained higher level at 8 h and 24 h after HI.The level of HIF-1α protein was much higher in HI and DFO-treated groups than those in sham controls （P〈0.05）.The synthetic level of HIF-1α protein were higher in DFO-treated groups than those in HI groups at each time point （P〈0.05）.HIF-1α mRNA expression was higher in DFO-treated groups than those in HI groups at each time point.Conclusions DFO upregulate HIF-1α protein and mRNA expression in neonatal rats with HIBD.The peak of HIF-1α protein expression are also more advanced and lasted longer after DFO-treatment.