INTRODUCTION: Metabolic syndrome (MetS) is a chronic metabolic disorder whose global prevalence continues to rise, imposing a significant burden on public health. With the development of round-the-clock societies, shift work has become increasingly commonplace. A growing body of epidemiological evidence indicates that circadian rhythm disruption constitutes a predictable risk factor for MetS; however, the precise mechanisms underlying this relationship remain inadequately understood. This study employed golden hamsters as a model to investigate the effects of circadian rhythm disruption simulated by cyclic light (CL) exposure on MetS.
METHODS: Thirty-three male golden hamsters (7 weeks old, body weight 120-160 g) were randomly assigned to four groups for a 6-week intervention: the Control group (normal light + normal diet, ND), the high-fat diet group (normal light + HFD, to induce a MetS model), the cyclic light group (CL + normal diet, CL), and the CL + HFD group (CL + HFD). Outcome measures included metabolic indicators, hepatic histopathology, and gut microbiota (analyzed via 16S rDNA sequencing).
RESULTS: The stability of the MetS model was assessed through measurements of body weight, fasting blood glucose, and total cholesterol levels. The results indicated that CL exposure may further aggravate metabolic disorders associated with MetS. Furthermore, it was observed that CL exposure intensified MetS-related disturbances in gut microbiota, evidenced by an increase in α-diversity and distinct separation in β-diversity. CL exposure in the MetS model golden hamsters resulted in a reduced abundance of Bacteroidetes and Weissella, alongside an overgrowth of Helicobacter.
DISCUSSION: Circadian rhythm disruption is an independent risk factor for MetS. It further exacerbates metabolic indicators by inducing gut microbiota dysbiosis and promoting the growth of harmful bacteria. Future research should integrate functional metabolomics with faecal microbiota transplantation studies to validate causal mechanisms and explore clinical translational value.
CONCLUSION: Circadian rhythm disruption is an independent risk factor for MetS. It exacerbates the pathological progression of MetS by reducing beneficial bacteria and promoting the growth of harmful bacteria, thereby further damaging its metabolic indicators.
