Effect and potential mechanism of photobiomodulation therapy on cognitive deficits in animal models of Alzheimer's disease: a systematic review and meta-analysis
Abstract
BACKGROUND
As a progressive neurodegenerative disorder, Alzheimer's disease (AD) has limited effective therapeutic options. Photobiomodulation (PBM) therapy, a non-invasive light therapy, represents a potential strategy for neurological diseases; however, its preclinical findings have been inconsistent. While previous reviews have summarized PBM's potential, this study is the first quantitative meta-analysis synthesizing preclinical evidence of PBM therapy in AD animal models, evaluating its effects on cognitive and neuropathological outcomes.
METHODS
We performed a systematic search across seven electronic databases to identify all relevant studies. A meta-analysis of 16 eligible studies evaluated the effects of PBM on cognitive outcomes and key neuropathological markers. Subgroup analyses were stratified by animal model and interventions (wavelength, energy density).
RESULTS
From 16 eligible studies, the meta-analysis found that PBM therapy significantly improved cognitive function (e.g., learning ability: MD = - 7.18; 95% CI - 9.87 to - 4.48), based on data from 386 animals. However, this was associated with significant heterogeneity (I2 = 88%, p < 0.00001). PBM also significantly reduced Aβ deposition (SMD = - 0.96; I2 = 55%) and p-Tau levels (SMD = - 2.24; I2 = 14%). From a mechanistic standpoint, the activity of cytochrome c oxidase (CCO) is enhanced by PBM therapy. Subgroup analysis by animal model showed that PBM therapy was associated with greater improvement of…
How strong is the evidence?
Evidence Hub reads this as a meta-analysis, done in animal, not in people. Its evidence level is 5 of 5 (Very low · case / narrative / animal / in vitro / in silico). Case reports, narrative reviews, and animal, cell or computer-model studies give the weakest evidence for human health.
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