Indirect application of near infrared light induces neuroprotection in a mouse model of parkinsonism – An abscopal neuroprotective effect

Near infrared light mitigates cerebellar pathology in transgenic mouse models of dementia

“…Barriers to clinical translation of these findings include the size of the human brain and the attenuation of the radiation directed transcranially by the scalp and skull, and by brain tissue itself [31]. Recent developments, such as the creation of an implantable optic fibre device to deliver NIr intracranially to deep brain structures such as the midbrain [31] and the discovery that targeting NIr at a remote tissue is neuroprotective [32], provide hope that this barrier will soon be overcome.…”

Prion Protein Signaling in the Nervous System—A Review and Perspective

“…253 These wavelengths have been found to be neuroprotective when applied to the brain in the prevention of Parkinson's disease in an animal model. 252 In addition, neurogenesis has been demonstrated when exogenous pulsing photons (800 nm) are applied to an axon, which may mimic the near-light emitted by cells as communication from nearby cells. 160 The neurogenesis is also influenced by membrane-anchored proteins (axonal guidance by PrP C ).…”

“…Upregulation of phagocytosis by PrP C would result in an increase in endogenous photons. Exogenous photons applied to other body areas, apart from the brain, in the same animal model 252 result in neuroprotection through an abscopal effect. 234 Interestingly, asymmetric disease is associated with abnormal left-right symmetry of global photon emission from the body.…”

The potential of light therapy in Parkinson's disease

“…47,60,68 It remains to be determined which of these mechanisms, direct or indirect, offers the neuroprotection, but we note that they are not mutually exclusive and that both may contribute to the process. 71,72,78 As a working hypothesis, direct stimulation of the mitochondria, which is supported by the most compelling evidence (as described above), is likely to form the primary mechanism of protection by light therapy, while the indirect stimulation of immune and/or stem cells may form a secondary and supportive mechanism. Some early results in an animal model of Parkinson's disease indicate that, although there is some neuroprotection of the brain after remote application of light therapy (eg, dorsum of body), the neuroprotection is not as great as when light therapy is applied directly to the head.…”

“…70 Intriguingly, neuroprotection of the mouse brain has been demonstrated after application of light to the dorsum of the animal, with no direct irradiation of the head. 71,72 While the mechanism remains unknown, it could involve the stimulation of one or more circulating molecules or cell types. One possibility is the stimulation of immune cells, for example mast cells and macrophages, could help neuroprotect cells in the brain.…”