Effect of Long-Term Continuous Light Exposure and Western Diet on Adropin Expression, Lipid Metabolism, and Energy Homeostasis in Rats

SIMPLE SUMMARY: Behavioral characteristics of living organisms may affect the metabolism and its underlying molecular basis. The lifestyles of some modern communities include prolonged light exposure at night, and a high-fat/high-sugar-containing diet is frequently investigated. The molecular mechanisms of this unhealthy behavior might involve Adropin and some related nuclear receptors. This study examines the effect of long-term continuous light exposure and high fat/sucrose (HFS) diet on Adropin expression, RORα, Rev-erb-α nuclear receptors, key enzymes of lipid metabolism, and energy homeostasis in a rat model. The results of this study demonstrate the deleterious effects of this modern behavior on the metabolism, histology of many organs and general health. In conclusion CL and WD produced widespread derangements of energy homeostasis and lipid metabolism. The pathogenesis of this disturbance includes, at least in part, the Adropin hormone with the involvement of the RORα and Rev-erb-α nuclear receptors. Future therapeutic potential may involve Adropin. ABSTRACT: Long-term continuous light exposure (CL) and western diet (WD) effects on Adropin expression, RORα, and Rev-erb-α nuclear receptors and energy homeostasis were studied in rats. Thirty-two male Wistar rats (250–290 g) were enrolled for 3 months in the following groups (n = 8/group): (a) Normal control group (NC), (b) CL group, (c) WD group, and (d) CL + WD group. Then, indirect calorimetry and food intake (FI) were measured. Finally, Adropin, hormone-sensitive lipase (HSL), adipocyte triglyceride lipase (ATGL), and free fatty acids (FFA) were measured. Additionally, the histopathology and gene expression of Enho, RORα, and Rev-erb-α genes were done. The CL alone elevated the Adropin plasma level and gene expression, increased RORα expression, and decreased the Rev-erb-α nuclear receptor expression mainly in the liver and kidney. Besides, CL increased the total energy expenditure (TEE) and decreased the respiratory quotient. WD alone or in combination with the CL reversed gene expression of Enho, RORα, and Rev-erb-α. Combined CL and WD increased the TEE, reduced the food intake, increased the ATGL, and reduced the Adropin level in addition to widespread degenerative changes in the liver, spleen, and renal tissues. The deleterious effects of CL and WD on energy homeostasis may include Adropin with the involvement of the RORα and Rev-erb-α nuclear receptors.