Parkinson’s disease ranks as the second most common neurodegenerative disorder globally. Its core pathology lies in the progressive demise of dopamine-producing neurons in the brain’s substantia nigra region. Existing drugs and surgeries can only relieve motor signs like tremors and stiffness; they cannot stop the relentless neuronal degeneration, and they often come with side effects and operative risks. Photobiomodulation (PBM) is a non-invasive light-based therapy that uses low-power red or near-infrared irradiation. It works by stimulating mitochondrial cytochrome c oxidase (CCO), boosting ATP energy synthesis, and regulating oxidative stress pathways. Over recent years, PBM has emerged as a promising investigational approach for neurodegenerative conditions.

A research team led by Professor Lei Chen at Hefei University of Technology, China, in collaboration with multiple hospitals including the First Affiliated Hospital of University of Science and Technology of China (Anhui Provincial Hospital), the First Affiliated Hospital of Anhui Medical University, the First Affiliated Hospital of Anhui Medical University North District: Anhui Public Health Clinical Center, and the First Affiliated Hospital of Anhui University of Chinese Medicine, systematically compared the therapeutic efficacy of three light sources in the paraquat-induced acute Parkinson’s disease mouse model: narrowband 670 nm LED-chip light (precisely matching one of the absorption peaks of cytochrome c oxidase, CCO, with a primary effect on energy supply), broadband 840 nm phosphor-converted LED light (covering 600–1000 nm, matching multiple CCO absorption peaks), and their combination. The results were unexpected—the combined phototherapy significantly outperformed than either single type of light source alone. It reduced the oxidative stress marker 4-HNE-positive cells by nearly 13%, increased myelin basic protein (MBP) expression by 18%, and restored dopamine transporter (DAT) levels to 86% of normal. The study on photophysiology revealed that the narrowband 670 nm light alone was efficient in enlarging neuronal somata and promoting neurite outgrowth, while the broadband 840 nm light was efficient in reducing neuronal vacuolation and promoting neurite branching. Their combination achieved comprehensive improvements in neuronal soma size, synaptic network, and cell alignment density. The team proposed an “energy-repair” synergistic hypothesis: the narrowband 670 nm light provided ATP energy as “fuel,” while the broadband 840 nm light initiated antioxidant and neurorepair pathways, establishing a positive feedback loop between energy supply and repair demands, ultimately yielding multi-target integrated regulation. In terms of safety, none of the light regimens caused any damage to the heart, liver, spleen, lungs, or kidneys. This study lays a solid foundation for personalized photobiomodulation based on spectrally guided strategies in Parkinson’s disease.
DOI：10.2738/foe.2026.0031