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Updated: Mar 18, 2026
A Protocol for Transcranial Photobiomodulation Therapy in Mice
Published on: November 18, 2018
Near-infrared light treatment reduces astrogliosis in MPTP-treated monkeys
Nabil El Massri1, Cécile Moro2, Napoleon Torres2
1Department of Anatomy F13, University of Sydney, Sydney, 2006, Australia.
Abstract:
We have reported previously that intracranial application of near-infrared light (NIr) reduces clinical signs and offers neuroprotection in a subacute MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) monkey model of Parkinson's disease. In this study, we explored whether NIr reduces the gliosis in this animal model. Sections of midbrain (containing the substantia nigra pars compacta; SNc) and striatum were processed for glial fibrillary acidic protein (to label astrocytes; GFAP) and ionised calcium-binding adaptor molecule 1 (to label microglia; IBA1) immunohistochemistry. Cell counts were undertaken using stereology, and cell body sizes were measured using ImageJ. Our results showed that NIr treatment reduced dramatically (~75 %) MPTP-induced astrogliosis in both the SNc and striatum. Among microglia, however, NIr had a more limited impact in both nuclei; although there was a reduction in overall cell size, there were no changes in the number of microglia in the MPTP-treated monkeys after NIr treatment. In summary, we showed that NIr treatment influenced the glial response, particularly that of the astrocytes, in our monkey MPTP model of Parkinson's disease. Our findings raise the possibility of glial cells as a future therapeutic target using NIr.
Insights
Near-infrared light (NIr) therapy significantly reduced astrocyte activation in a Parkinson
Area of Science:
- Neuroscience
- Biomedical Engineering
- Cell Biology
Background:
- Parkinson's disease is a neurodegenerative disorder characterized by the loss of dopaminergic neurons.
- Gliosis, the activation of glial cells (astrocytes and microglia), is a key pathological feature in Parkinson's disease.
- Near-infrared light (NIr) has shown neuroprotective effects in preclinical models of Parkinson's disease.
Purpose of the Study:
- To investigate the effect of NIr treatment on gliosis in a subacute MPTP-induced monkey model of Parkinson's disease.
- To quantify changes in astrocyte and microglia populations and morphology following NIr application.
- To explore NIr as a potential therapeutic strategy targeting glial responses in Parkinson's disease.
Main Methods:
- MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) was used to induce Parkinsonism in monkeys.
- Intracranial NIr treatment was administered to the affected animals.
- Immunohistochemistry for glial fibrillary acidic protein (GFAP) and ionised calcium-binding adaptor molecule 1 (IBA1) was performed on midbrain and striatal sections.
- Stereology and ImageJ software were used for cell counting and size measurement.
Main Results:
- NIr treatment significantly reduced MPTP-induced astrogliosis by approximately 75% in both the substantia nigra pars compacta (SNc) and striatum.
- NIr treatment had a limited impact on microglia, with no significant changes in cell number observed.
- A reduction in microglial cell body size was noted after NIr treatment.
Conclusions:
- NIr treatment effectively modulates the glial response, particularly astrogliosis, in a primate model of Parkinson's disease.
- These findings suggest that glial cells, especially astrocytes, could be a viable therapeutic target for NIr intervention in Parkinson's disease.
- NIr therapy presents a promising non-invasive approach for managing Parkinson's disease pathology by influencing glial cell activity.
