Melatonin Alleviates Glucose and Lipid Metabolism Disorders in Guinea Pigs Caused by Different Artificial Light
Wei Liu1, Yunchao Zhang1, Qi Chen1
1Department of Endocrinology and Metabolism, Jiangsu Province Hospital of Chinese Medicine, Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing 210029, China.
Abstract:
Modern lifestyle-associated factors, such as high-calorie intake, high-fat diet (HFD), and excessive artificial light, are risk factors for glucose and lipid metabolism disturbances. Melatonin may be beneficial for managing obesity and diabetes; however, the underlying molecular mechanisms are not well elucidated. We aimed to assess whether melatonin has beneficial effects on constant artificial light-induced fat deposition, lipid metabolism, and insulin resistance. Guinea pigs were randomly divided into five experimental groups: control (C), HFD (H), 12 h light (12HL), 24 h light (24HL), and melatonin (M). The majority of indexes, including insulin resistance and obesity, were measured after 10 weeks. AMP-activated protein kinase α (AMPKα)/peroxisome proliferator-activated receptor-α (PPARα) pathway expression was analyzed by quantitative reverse transcription PCR and western blotting. Although insulin resistance and obesity indexes were higher in the 24HL group than in the 12HL group, they were significantly lower in the M group than in the 24HL group. Melatonin treatment markedly upregulated AMPKα, phosphorylated AMPKα (p-AMPKα), PPARα, and carnitine palmitoyl-CoA transferase 1 A (CPT1A) gene and protein expression. Melatonin may alleviate insulin resistance and obesity caused by persistent artificial light exposure in guinea pigs, likely via activation of the AMPKα/PPARα signaling pathway.
Insights
Melatonin may help reduce obesity and insulin resistance caused by artificial light exposure. This study shows melatonin activates the AMPKα/PPARα pathway, improving metabolic health.
Area of Science:
- Metabolic research
- Endocrinology
- Chronobiology
Background:
- Modern lifestyles, including high-calorie diets and artificial light, disrupt glucose and lipid metabolism.
- Melatonin shows potential for managing obesity and diabetes, but its mechanisms are unclear.
Purpose of the Study:
- To investigate melatonin's effects on fat deposition, lipid metabolism, and insulin resistance induced by constant artificial light.
- To explore the molecular pathways, specifically the AMPKα/PPARα signaling pathway, involved in melatonin's metabolic effects.
Main Methods:
- Guinea pigs were exposed to different light conditions (12h light, 24h light) and/or high-fat diets, with some receiving melatonin treatment.
- Metabolic parameters including insulin resistance and obesity were assessed after 10 weeks.
- Gene and protein expression of the AMPKα/PPARα pathway and CPT1A were analyzed using qPCR and Western blotting.
Main Results:
- Constant artificial light (24HL) worsened insulin resistance and obesity compared to intermittent light (12HL).
- Melatonin treatment significantly reduced insulin resistance and obesity markers compared to the 24HL group.
- Melatonin upregulated key pathway proteins: AMPKα, p-AMPKα, PPARα, and CPT1A.
Conclusions:
- Melatonin may mitigate insulin resistance and obesity associated with prolonged artificial light exposure in guinea pigs.
- The beneficial effects of melatonin appear to be mediated through the activation of the AMPKα/PPARα signaling pathway.
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