NQO1 and Alzheimer disease: As shown in Fig. 6A, compared with age-matched control mice, the AD mice (AD + saline) displayed a remarkably higher level of Nrf2 (Fig. 6B, P < 0.001), HO-1 (Fig. 6D, P < 0.001), NQO1 (Fig. 6E, P < 0.001), iNOS (Fig. 6F, P < 0.001), and a lower level of Keap1 protein expression (Fig. 6C, P < 0.001), while EVs treatment reversed the expression of these proteins (Fig. 6B-F, P < 0.05) that observed in the hippocampus of AD model.