Effects of chronic forced circadian desynchronization on body weight and metabolism in male mice

CASIRAGHI LP; ALZAMENDI, A; GIOVAMBATTISTA , ANDRÉS; CHIESA JJ; GOLOMBEK D

Physiological Reports

Wiley online library

Año: 2016 vol. 8 p. 1 - 12

Metabolic functions are synchronized by the circadian clock setting daily patternsof food intake, nutrient delivery, and behavioral activity. Here, we studythe impact of chronic jet-lag (CJL) on metabolism, and test manipulationsaimed to overcome potential alterations. We recorded weight gain in C57Bl/6mice under chronic 6 h advances or delays of the light?dark cycle every2 days (ChrA and ChrD, respectively). We have previously reported ChrA, butnot ChrD, to induce forced desynchronization of locomotor activity rhythmsin mice (Casiraghi et al. 2012). Body weight was rapidly increased underChrA, with animals tripling the mean weight gain observed in controls by day10, and doubling it by day 30 (6% vs. 2%, and 15% vs. 7%, respectively). Significantincreases in retroperitoneal and epidydimal adipose tissue masses(172% and 61%, respectively), adipocytes size (28%), and circulating triglycerides(39%) were also detected. Daily patterns of food and water intake wereabolished under ChrA. In contrast, ChrD had no effect on body weight.Wheel-running, housing of animals in groups, and restriction of food availabilityto hours of darkness prevented abnormal increase in body weightunder ChrA. Our findings suggest that the observed alterations under ChrAmay arise either from a direct effect of circadian disruption on metabolism,from desynchronization between feeding and metabolic rhythms, or both.Direction of shifts, timing of feeding episodes, and other reinforcing signalsdeeply affect the outcome of metabolic function under CJL. Such featuresshould be taken into account in further studies of shift working schedules inhumans.