Melatonin restores hippocampal neural precursor cell proliferation and prevents cognitive deficits induced by jet lag simulation in adult mice.
Frequent flyers and shift workers undergo circadian dysrhythmia with adverse impact on body and mind. The circadian rhythm disorder "jet lag" disturbs hippocampal neurogenesis and spatial cognition, which represent morphological and functional adult brain plasticity. This raises the question if pro-neurogenic stimuli might prevent those consequences. However, suitable measures to mitigate jet lag-induced adverse effects on brain plasticity have been neglected so far. Here, we used adult C57Bl6 mice to investigate the pro-neurogenic stimuli melatonin (8 mg/kg i.p.) as well as environmental enrichment as potential measures. We applied photoperiod alterations to simulate "jet lag" by shortening the dark period every third day by 6 hours for 3 weeks. We found that "jet lag" simulation reduced hippocampal neural precursor cell proliferation by 24% and impaired spatial memory performance in the water maze indicated by a prolonged swim path to the target (~23%). While melatonin prevented both the cellular (~1%) as well as the cognitive deficits (~5%), environmental enrichment only preserved precursor cell proliferation (~12%). Our results indicate that lifestyle interventions are insufficient to completely compensate jet lag-induced consequences. Instead, melatonin is required to prevent cognitive impairment caused by the same environmental factors to which frequent flyers and shift workers are typically exposed to.
Department of Neurology, Charité-Universitätsmedizin Berlin, Berlin, Germany.|Department of Neurology, University Hospital of Cologne, Cologne, Germany.
Deetje
http://orcid.org/0000-0001-8778-5127
D
Iggena
Deparment of Neurobiology, Humboldt-University Berlin, Berlin, Germany.
York
Y
Winter
Department of Neurology, Charité-Universitätsmedizin Berlin, Berlin, Germany.
Barbara
B
Steiner
D000818:Animals; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002492:Central Nervous System Depressants / Q000494:pharmacology; D002940:Circadian Rhythm / Q000187:drug effects; D003071:Cognition / Q000187:drug effects; D005260:Female; D005455:Fluorescent Antibody Technique; D006624:Hippocampus / Q000166:cytology*; D007150:Immunohistochemistry; D020179:Jet Lag Syndrome / Q000503:physiopathology*; D008550:Melatonin / Q000494:pharmacology*; D051379:Mice; D008810:Mice, Inbred C57BL; D017440:Photoperiod
D002492:Central Nervous System Depressants; D008550:Melatonin
adult neurogenesis; hippocampus; jet lag; melatonin; photoperiod alterations; spatial memory