HIF1A and brain ischemia: There was only a small increase in the number of HIF-1α positive cells in the cortical area after 6 h and 1 d of cerebral ischemia-reperfusion, and the difference in the number of HIF-1 positive cells after 6 h and 1 d was not statistically significant compared with the control group (P > 0.05); however, by 3 d, there was a significant increase in the number of HIF-1α positive cells, which was statistically significant compared with the control group (P < 0.05).