Highlights
- The gut microbiota plays a central role in immune regulation, inflammation, and brain function through the gut–brain axis.
- Intestinal dysbiosis contributes to neuroinflammation and increased blood–brain barrier permeability.
- Photobiomodulation (PBM) shows potential to modulate gut microbiota composition and inflammatory signaling.
- Preclinical evidence supports PBM effects on mitochondrial function, cytokine modulation, and immune balance.
- Human clinical trials are still limited, highlighting the need for standardized protocols.
Background
The gut–brain axis represents a bidirectional communication network linking intestinal microbiota, immune signaling, and central nervous system function. Disruptions in gut microbial balance can promote peripheral inflammation, compromise blood–brain barrier integrity, and contribute to neuroinflammatory and neurodegenerative conditions.
Role of Photobiomodulation
Photobiomodulation (PBM), formerly referred to as low-level laser therapy (LLLT), has been extensively studied for its anti-inflammatory, immunomodulatory, and tissue-repair properties. Emerging evidence suggests that PBM applied to the intestinal region may influence gut microbiota composition and systemic inflammation.
Key Findings from the Review
According to the reviewed studies, PBM may:
- Improve gut microbial diversity
- Reduce pro-inflammatory cytokines such as IL-1β, IL-6, and TNF-α
- Enhance mitochondrial function and ATP production
- Modulate immune responses, potentially reducing neuroinflammation
Potential Clinical Applications
The review highlights PBM as a promising adjunct therapy for conditions influenced by the gut–brain axis, including:
- Neurodegenerative diseases (Alzheimer’s disease, Parkinson’s disease, multiple sclerosis)
- Neurodevelopmental and mood disorders (autism spectrum disorder, anxiety, depression)
- Inflammatory bowel disease and metabolic syndrome
Takeaway
Photobiomodulation represents a non-invasive, drug-free strategy with potential to modulate gut dysbiosis and its downstream neuroinflammatory effects. While preclinical findings are encouraging, further human clinical trials with standardized PBM protocols are required to confirm therapeutic efficacy.
Reference: da Silva, L. E., Martins, D. F., de Oliveira, M. P., Stenier, M. R., Fernandes, B. B., Willemann, S. D. S., de Souza, G., Vieira, W. F., Hewitson, A., Cidral-Filho, F. J., & Rezin, G. T. (2025). Photobiomodulation of gut microbiota with low-level laser therapy: a light for treating neuroinflammation. Lasers in medical science, 40(1), 64. https://doi.org/10.1007/s10103-025-04319-9