Investigating the effect of transcranial low power laser therapy onstress

Low-level laser therapy (LLLT) or photobiomodulation (PBM) is a possibletreatment for brain injury, including traumatic brain injury (TBI). Methods: We review thefundamental mechanisms at the cellular and molecular level and the effects on the brain arediscussed. There are several contributing processes that have been proposed to lead to thebeneficial effects of PBM in treating TBI such as stimulation of neurogenesis, a decrease ininflammation, and neuroprotection. Both animal and clinical trials for ischemic stroke areoutlined. A number of articles have shown how transcranial LLLT (tLLLT) is effective atincreasing memory, learning, and the overall neurological performance in rodent models withTBI. Results: Our laboratory has conducted three different studies on the effects of tLLLT onmice with TBI. The first studied pulsed against continuous laser irradiation, finding that ۱۰ Hzpulsed was the best. The second compared four different wavelengths, discovering only ۶۶۰and ۸۱۰ nm to have any effectiveness, whereas ۷۳۲ and ۹۸۰ nm did not. The third looked atvarying regimens of daily laser treatments (۱, ۳, and ۱۴ days) and found that ۱۴ laserapplications was excessive. We also review several studies of the effects of tLLLT onneuroprogenitor cells, brain-derived neurotrophic factor and synaptogenesis, immediate earlyresponse knockout mice, and tLLLT in combination therapy with metabolic inhibitors.Conclusions: Finally, some clinical studies in TBI patients are covered.

Keywords:

traumatic brain injury , photobiomodulation , stroke , low-level laser therapy , brain disorders