Photobiomodulation with near infrared light mitigates Alzheimer’s disease-related pathology in cerebral cortex – evidence from two transgenic mouse models

Abstract

IntroductionPrevious work has demonstrated the efficacy of irradiating tissue with red to infrared light in mitigating cerebral pathology and degeneration in animal models of stroke, traumatic brain injury, parkinsonism and Alzheimer’s disease (AD). Using mouse models, we explored the neuroprotective effect of near infrared light (NIr) treatment, delivered at an age when substantial pathology is already present in the cerebral cortex.MethodsWe studied two mouse models with AD-related pathologies: the K369I tau transgenic model (K3), engineered to develop neurofibrillary tangles, and the APPswe/PSEN1dE9 transgenic model (APP/PS1), engineered to develop amyloid plaques. Mice were treated with NIr 20 times over a four-week period and histochemistry was used to quantify AD-related pathological hallmarks and other markers of cell damage in the neocortex and hippocampus.ResultsIn the K3 mice, NIr treatment was associated with a reduction in hyperphosphorylated tau, neurofibrillary tangles and oxidative stress markers (4-hydroxynonenal and 8-hydroxy-2′-deoxyguanosine) to near wildtype levels in the neocortex and hippocampus, and with a restoration of expression of the mitochondrial marker cytochrome c oxidase in surviving neurons. In the APP/PS1 mice, NIr treatment was associated with a reduction in the size and number of amyloid-β plaques in the neocortex and hippocampus.ConclusionsOur results, in two transgenic mouse models, suggest that NIr may have potential as an effective, minimally-invasive intervention for mitigating, and even reversing, progressive cerebral degenerations.

Management of Post-Traumatic Stress (PTSD) Dementia and Other Neuro-Degenerative Disease with Photo-Medicine: Clinical Experience and Case Studies

“…These results when taken together with those other models of neurodegeneration strengthen the notion that LLLT is a viable neuro-protective treatment for a range of neruodegenerative conditions. We believe this growing body of work provides the impetus to begin trialing LLLT as a broad base therapy for AD and other neurodegenerations [12]. Promising work was published in Japan by Kazuyoshi Zenba.…”

Near infra-red light treatment of Alzheimer’s disease

“…NIR treatment modestly reduced the small-size plaques, which was consistent with a previous study. 19 There was signi¯cant di®erence (p < 0.05) between the two groups for plaques measuring <20 m. And for plaques measuring !20 m, p value was bigger than 0.05. The small sample size and short duration of irradiation might contribute to large p value.…”

“…Purushothuman et al studied two mouse models with NIR treatment, and found out that NIR treatment could reduce hyperphosphorylated tau, neuro¯brillary tangles, oxidative stress markers and plaques. 19 They then extended the irradiated area to cerebellum. After one month of treatment, NIR mitigated AD-related pathologies.…”

“…18 Purushothuman et al applied 670 nm NIR to two kinds of transgenic mouse models,¯nding out that NIR was associated with a reduction in hyperphosphorylated tau, neuro¯brillary tangles, oxidative stress markers and A plaques in the neocortex and hippocampus. 19 We used a transgenic AD mouse model to evaluate the e®ect of NIR. The mouse model was coinjected with two mutant gene vectors involving APP and PSEN1.…”

“…[13][14][15] Studies have indicated the e®ects of NIR on nervous system, like AD. [16][17][18][19] The biological e®ects of NIR are speci¯c to wavelength and not based on thermal e®ects. Those studies showed NIR mitigated AD neuropathology and behavioral de¯cits.…”