In this study, we performed bilateral common carotid artery stenosis (BCAS) to induce CCH in the LepR-deficient db/db mice, aiming to evaluate the possible involvement of leptin in CCH-induced cognitive impairment, WMLs, and neuroinflammation, and further explore the effect of leptin on chronic hypoxia-induced inflammation using the BV2 microglial cell line. The gene discussed is LEP; the disease is Cognitive impairment.