The effects of probiotics and exercise on preventing neurodegenerative diseases associated with circadian rhythm disruption: Focus on gut-brain axis

Circadian rhythm disruption is increasingly recognized as a contributing factor in the onset and progression of neurodegenerative diseases (NDs). Emerging evidence highlights the critical role of the gut microbiota in regulating brain function via the gut-brain axis (GBA), particularly in modulating neuroinflammation and glial cell homeostasis. Probiotics can remodel the gut microbial composition, restore microbial homeostasis, and promote the production of beneficial microbial metabolites, such as short-chain fatty acids (SCFAs) and tryptophan-derived compounds, which play vital roles in maintaining brain health. This review explores the neuroprotective effects of probiotics, emphasizing their role in modulating the GBA and glial cells. We also discuss the synergistic potential of combining probiotics with exercise as a strategy to mitigate circadian rhythmrelated neurodegeneration, providing new insights into their preventive role in NDs.