We plan to measure the expression of HIF-1α in the brains of mice with AD and assess cognitive impairment, Aβ clearance, BBB injury, and angiogenesis in the brain after blocking HIF-1α activity to comprehensively evaluate the possible role of the HIF-1 signalling pathway in the neuroprotective effect of Icariin against AD. The gene discussed is HIF1A; the disease is Cognitive impairment.