Objective： To investigate the association of hypoxia-inducible factor-1α （HIF-1α） expression and apoptosis in the cerebral cortex following subarachnoid hemorrhage （SAH）.
Methods： Subarachnoid hemorrhage was induced by modified monofilament puncture method in rats.Thirty-five adult male Sprague-Dawley rats were randomly assigned to five groups: sham-operated group，SAH 6 h，SAH 12 h，SAH 24 h and SAH 72 h groups.HIF-1α expression was assessed by immunofluorescence staining.TdT-mediated dUTP-biotin nick end-labeling （TUNEL） technique was adopted to detect apoptotic cells.Double immunolabeling was used to identify cell types with positive HIF-1α expression.
Results： The expression of HIF-1α was increased at 6 h （4.65%±1.01%），peaked at 24 h （18.55%±4.23%），and decreased at 72 h （6.31%±1.15%） after SAH （P<0.05）.TUNEL-positive cells were up-regulated in the brain at 6 h （7.09%±2.34%），peaked at 24 h （25.54%±7.36%），and down-regulated at 72 h （14.11%±3.03%） after SAH （P<0.05）.A significant positive correlation was noted between HIF-1α positive rates and TUNEL positive rates following SAH （r=0.738，P<0.05）.Double immunolabeling indicated that HIF-1α was expressed predominantly in neurons and some nuclei with positive HIF-1α were co-stained with TUNEL.
Conclusion： The data indicate that HIF-1α might participate in the pathological progression of early brain injury after SAH.