Improvement of walnut-derived peptides on inflammation and oxidative stress in BV-2 microglia and cognitive impairment in mice

The research aimed to investigate the underlying anti-inflammatory and antioxidative mechanisms of walnut-derived peptides in BV-2 microglia with H 2 O 2 -induced injury, and to further assess their neuroprotective properties against cognitive impairments caused by lipopolysaccharide (LPS) in mice. The findings indicated that both walnut-derived peptides NPFD and LDAF significantly inhibited ROS production in H 2 O 2 -injured BV-2 microglia and attenuated oxidative stress in BV-2 microglial cells via the Nrf2/keap1 signaling pathway. In addition, LDAF showed greater improvement in inflammatory than NPFD in H 2 O 2 -injured BV-2 microglia. Meanwhile, The MWM demonstrated that LDAF had the potential to mitigate memory impairments caused by LPS through normalizing the brain's inflammatory responses and reducing oxidative stress. And LDAF treatment improved neuronal cell morphology in the hippocampal region of mouse brain tissue and increased the number of Nissl bodies in neurons of injured mice. These results showed that LDAF was able to improve spatial cognitive ability in mice by reducing inflammation and oxidative stress.