Dityrosine administration induces novel object recognition deficits in young adulthood mice.

Dietary modifications have been shown to contribute to the physical and mental diseases. Oxidative modifications of protein can be easily found in protein-rich food such as meat and milk products. Previous studies mainly focus on the consequences of lipid oxidation products intake in vivo, but the effects of protein oxidation products consumption have been largely neglected. Oxidants have been shown to play an important role in aging and neurodegenerative diseases. Dityrosine is the oxidated product of tyrosine residues in protein which is considered as a biomarker for oxidative stress, but the potential deleterious effects of dityrosine are unknown. In the present study, we explored the effects of dityrosine administration on the behavioral aspect. We found that dityrosine-ingested mice displayed impaired memory during novel object recognition test, but no influence to the spatial memory in Morris water maze compared with the saline group. Other aspects of neurobehavioral function such as locomotor activity, anxiety and social behavior were not affected by dityrosine ingestion. Furthermore, we found that dityrosine-ingested mice showed decreased expression level of NMDA receptor subunits Nr1, Nr2a, Nr2b as well as Bdnf, Trkb. Our study suggests that dityrosine exposure impairs hippocampus-dependent nonspatial memory accompanied by modulation of NMDA receptor subunits and Bdnf expression.