Impact of constant light-induced circadian disruption on hepatic lipid metabolism: Evaluating the effects of GABA oolong tea extract

Disruptions in circadian rhythms have been associated with metabolic disorders such as obesity and fatty liver disease. This study aimed to evaluate the effects of GABA oolong tea extract (OTE) on metabolic disturbances induced by constant light (LL) exposure and a high-fat diet (HFD) in mice. The results showed that LL alone did not induce obesity but significantly reduced food intake and water consumption while increasing food conversion efficiency and blood glucose levels. In contrast, LL + HFD led to significant weight gain, increased white, beige, and brown adipose tissue weights, larger adipocyte size, and severe hepatic lipid infiltration. At the molecular level, LL and LL + HFD significantly reduced hepatic AMPK phosphorylation and PPARα expression, impairing fatty acid β-oxidation and promoting triglyceride accumulation. OTE intervention decreased hepatic triglyceride levels but did not alleviate obesity or metabolic dysfunction. These findings suggest that LL exacerbates HFD-induced metabolic disturbances, and OTE may have limited protective effects under these conditions. Further studies with higher OTE dosages are warranted.