CLINATEC, EJ Safra Centre, CEA, LETI, University of Grenoble Alpes, France, Dept of Anatomy F13, University of Sydney, Australia, Dept of Physiology F13, University of Sydney, Australia

We have shown previously that when applied separately, 670 nm and 810 nm near infrared light (NIr) reduces behavioural deficits and offers neuroprotection in a MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) mouse model of Parkinson's disease. Here, we explored the beneficial outcomes when these NIr wavelengths were applied both together, either concurrently (at the same time) or sequentially (one after the other). Mice received MPTP injections (total of 50 mg/kg) and had extracranial application of 670 nm and/or 810 nm NIr. Behavioural activity was tested with an open-field test and brains were processed for tyrosine hydroxylase immunohistochemistry and stereology. Our results showed that when 670 nm and 810 nm NIr were applied both together and sequentially, there was a greater overall beneficial outcome – increased locomotor activity and number of tyrosine hydroxylase immunoreactive cells in the substantia nigra pars compacta – than when they were applied either separately, or in particular, both together and concurrently. In summary, our findings have important implications for future use of NIr therapy in humans, that there are some combinations of wavelengths that provide more beneficial outcome than others. © 2016 Elsevier Ireland Ltd and Japan Neuroscience Society

Open-field test, Parkinson's disease, Photobiomodulation, Substantia nigra

tyrosine 3 monooxygenase, animal experiment, animal model, animal tissue, Article, behavior, controlled study, immunocompetent cell, immunohistochemistry, infrared radiation, light intensity, locomotion, male, medical device, mouse, MPTP-induced parkinsonism, neuroprotection, nonhuman, open field test, phototherapy, priority journal, stereology, substantia nigra pars compacta, treatment outcome