Postoperative cognitive dysfunction (POCD) is characterized by impaired cognitive function following
general anesthesia and surgery. Oxidative stress is a significant pathophysiological manifestation underlying POCD. Previous studies have reported that the decline of
nicotinamide adenine dinucleotide (
NAD+) -dependent
sirtuin 1 (
SIRT1) contributes to the activation of oxidative stress. In this study, we investigated whether pretreatment of
nicotinamide mononucleotide (NMN), an NAD+ intermediate, improves oxidative stress and cognitive function in POCD. The animal model of POCD was established in C57BL/6 J mice through 6 h
isoflurane anesthesia-induced
cognitive impairment. Mice were intraperitoneally injected with NMN for 7 days prior to
anesthesia, after which oxidative stress and cognitive function were assessed. The level of oxidative stress was determined using flow cytometry analysis and assey kits. The fear condition test and the Y-maze test were utilized to evaluate contextual and spatial memory. Our results showed that
cognitive impairment and increased oxidative stress were observed in POCD mice, as well as downregulation of NAD+ levels and related
protein expressions of
SIRT1 and
nicotinamide phosphoribosyltransferase (NAMPT) in the hippocampus. And NMN supplementation could effectively prevent the decline of NAD+ and related
proteins, and reduce oxidative stress and
cognitive disorders after POCD. Mechanistically, the findings suggested that protection on cognitive function mediated by NMN pretreatment in POCD mice may be regulated by
NAD+-
SIRT1 signaling pathway. This study indicated that NMN preconditioning reduced oxidative stress damage and alleviated
cognitive impairment in POCD mice.