ENVIRONMENTAL LIGHT MODULATION MITIGATES PARKINSON’S DISEASE PATHOLOGY

Parkinson's disease (PD) is a prevalent neurodegenerative disorder characterized by progressive motor dysfunction. Emerging evidence links PD pathogenesis to gut microbiota dysbiosis, evidenced by early-onset gastrointestinal non-motor symptoms. Previous studies have shown that light exposure regulates gut circadian rhythms via the retina-brain-gut axis, environmental light cycles may play a critical role in PD progression. This study investigated whether dim light at night (dLAN) modulates gut microbiota to mitigate PD symptoms in PD mouse models.
We assessed motor behavior, fecal microbiota, plasma and fecal short-chain fatty acids (SCFAs), colonic gene expression, and tyrosine hydroxylase (TH) expressing neurons in the Substantia nigra pars compacta (SNpc). Results indicated that the experimental light condition reshaped gut microbiota composition and oscillation, leading to a potentially protective microbial profile. These microbial shifts correlated with restored metabolic profiles, including elevated SCFA levels in fecal and improved intestinal molecular expression, indicating a healthier gut environment and reduced inflammation. Crucially, these physiological improvements were accompanied by enhanced motor performance. Our findings suggest that manipulating environmental light can restore gut physiology, highlighting light-based interventions as a novel therapeutic strategy to modulate the gut-brain axis and delay PD motor dysfunction.