Time-restricted feeding alters isoflurane-induced memory deficits

Abstract

Food consumption during the rest phase promotes circadian desynchrony, which is corrected with harmful physiological and mental disorders. Previously, we found that circadian desynchrony was involved in isoflurane-induced cognitive impairment. Here, we scheduled food access to modulate daily rhythm to examine its impact on isoflurane-induced cognitive impairments. Mice were randomly transferred to restricted feeding (RF) time groups: Control group (Zeitgeber time (ZT) 0–ZT24, ad libitum feeding), Day-Feeding group (ZT0–ZT12, misaligned feeding), and Night-Feeding group (ZT12–ZT24, aligned feeding). Then, some of them were subjected to 5 h of 1.3% isoflurane anaesthesia from ZT14 to ZT19 and were divided into the Control + Anes group, the Day-Feeding + Anes group, and the Night-Feeding + Anes group. Mini-Mitter was used to monitor the daily rhythm. Fear conditioning system was conducted to assess cognition of mice. We observed that the Night-Feeding group adapted to RF gradually, whereas the Day-Feeding group exhibited a disturbed daily rhythm. The Night-Feeding + Anes group exhibited a partially enhanced daily rhythm, whereas the Day-Feeding + Anes group exhibited sustained phase advances and diurnality score increase 7 days after isoflurane anaesthesia. Notably, in tests of hippocampus-dependent contextual memory, the Night-Feeding + Anes group demonstrated decreased deficits; the Day-Feeding + Anes group showed prolonged post-anaesthetic deficits 14 days after isoflurane anaesthesia. However, amygdala-dependent cued-fear conditioning post-anaesthesia was not altered by the RF schedule. In conclusion, we demonstrated that misaligned feeding disturbed the daily rhythm and led to persistent post-anaesthetic cognitive dysfunction. Aligned feeding enhanced the daily rhythm partially and improved post-anaesthetic cognitive dysfunction.

Circadian disruption and human health

“…These and other factors can contribute to the low amplitude and misalignment of circadian rhythms at multiple levels of organization (7,31,(46)(47)(48)(49)(50)(51)(52)(53), which in turn have been shown to correlate with the degree of neurologic impairment (54,55). In mice, misalignment between feeding rhythms and the SCN results in memory impairment (56), which improves with timed feeding schedules (57). Furthermore, there is evidence for misalignment of neuronal activity in different brain regions, such as between the SCN and hippocampus (58,59).…”