Light intensity alters the effects of light-induced circadian disruption on glucose and lipid metabolism in mice.

Abstract

Circadian disruption induced by rotating light cycles has been linked to metabolic disorders. However, how the interaction of light intensity and light cycle affects metabolism under different diets remains to be explored. Eighty mice were first randomly stratified into the low-fat diet (LFD, n = 40) or high-fat diet (HFD, n = 40) groups. Each group was further randomly subdivided into four groups (n = 8-12 per group) in terms of different light intensities [lower (LI, 78 lx) or higher intensity (HI, 169 lx)] and light cycles [12-h light:12-h dark cycle or circadian-disrupting (CD) light cycle consisting of repeated 6-h light phase advancement]. Body weight was measured weekly. At the end of the 16-wk experiment, mice were euthanized for serum and pathological analysis. Glucose and insulin tolerance tests were performed during the last 2 wk. The CD cycle increased body weight gain, adipocyte area, glucose intolerance, and insulin resistance of LFD as well as HFD mice under HI but not LI condition. Moreover, the serum and hepatic triglyceride levels increased with LFD-HI treatment, regardless of light cycle. In addition, the CD cycle improved lipid and glucose metabolism under HFD-LI condition. In summary, the detrimental effects of the CD cycle on metabolism were alleviated under LI condition, especially in HFD mice. These results indicate that modulating light intensity is a potential strategy to prevent the negative metabolic consequences associated with jet lag or shift work.NEW & NOTEWORTHY Glucose and lipid homeostasis is altered by the CD cycles in a light-intensity-dependent manner. Lower-intensity light reverses the negative metabolic effects of the CD cycles, especially under HFD feeding. The interaction of light intensity and light cycle on metabolism is independent of energy intake and eating pattern. Glucose metabolic disorders caused by rotating light cycles occur along with compensatory β-cell mass expansion.

• Authors: Xiaojing Fan, Defu Chen, Ying Wang, Yizhou Tan, Hongyou Zhao, Jing Zeng, Yunqi Li, Xianghuan Guo, Haixia Qiu, Ying Gu
• Journal: American journal of physiology. Endocrinology and metabolism (Am J Physiol Endocrinol Metab) Vol. 322 Issue 1 Pg. E1-E9 (01 01 2022) ISSN: 1522-1555 [Electronic] United States
• PMID: 34719945 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Blood Glucose
• Insulin
• Triglycerides
• Cholesterol

Topics

• Animals
• Blood Glucose (analysis, metabolism)
• Cholesterol (blood)
• Circadian Clocks (radiation effects)
• Circadian Rhythm (radiation effects)
• Diet, Fat-Restricted
• Diet, High-Fat
• Eating (radiation effects)
• Glucose Intolerance (blood)
• Glucose Tolerance Test
• Insulin (blood)
• Insulin Resistance (radiation effects)
• Light
• Liver (metabolism)
• Locomotion (radiation effects)
• Male
• Mice
• Mice, Inbred C57BL
• Signal Transduction (radiation effects)
• Triglycerides (blood)
• Weight Gain (radiation effects)