Photobiomodulation of Cytochrome c Oxidase by Chronic Transcranial Laser in Young and Aged Brains

Abstract

In cellular bioenergetics, cytochrome c oxidase (CCO) is the enzyme responsible for oxygen consumption in the mitochondrial electron transport chain, which drives oxidative phosphorylation for adenosine triphosphate (ATP) production. CCO is also the major intracellular acceptor of photons in the light wavelengths used for photobiomodulation (PBM). Brain function is critically dependent on oxygen consumption by CCO for ATP production. Therefore, our objectives were (1) to conduct the first detailed brain mapping study of the effects of PBM on regional CCO activity, and (2) to compare the chronic effects of PBM on young and aged brains. Specifically, we used quantitative CCO histochemistry to map the differences in CCO activity of brain regions in healthy young (4 months old) and aged (20 months old) rats from control groups with sham stimulation and from treated groups with 58 consecutive days of transcranial laser PBM (810 nm wavelength and 100 mW power). We found that aging predominantly decreased regional brain CCO activity and systems-level functional connectivity, while the chronic laser stimulation predominantly reversed these age-related effects. We concluded that chronic PBM modified the effects of aging by causing the CCO activity on brain regions in laser-treated aged rats to reach levels similar to those found in young rats. Given the crucial role of CCO in bioenergetics, PBM may be used to augment brain and behavioral functions of older individuals by improving oxidative energy metabolism.

Neuromodulation of brain power topography and network topology by prefrontal transcranial photobiomodulation

“…One of these studies suggested the modulation of vasomotion in the cerebral vasculature stimulated by nitricoxide release as another effect of tPBM [30]. Furthermore, several recent studies showed the ability of tPBM of reversing the adverse effect of aging on oxidative energy metabolism in rats [31] and improving the flow of cerebrospinal fluid at sleep in humans [32,33]. However, the electrophysiological response of the human brain to tPBM is not well studied and understood.…”

The anti-inflammatory effects of photobiomodulation are mediated by cytokines: Evidence from a mouse model of inflammation

“…Much is already known about the underlying mechanisms of PBM. PBM is currently believed to exert its physiological effects on complex biological systems primarily through the photon-induced release of nitric oxide (NO) from cytochrome C oxidase (Cox) chromophores within mitochondria (also known as complex IV within the mitochondrial electron transport chain; Cardoso et al, 2022 ; Oh et al, 2022 ; Pope and Denton, 2022 ). This enzyme, which contains both heme and copper centers, absorbs light in the red and NIR regions of the spectrum ( Karu, 2010 ).…”

Use of either transcranial or whole‐body photobiomodulation treatments improves COVID‐19 brain fog

“…Besides these disease models with compromised neurocognition, there have been clear demonstrations of the ability of PBM to improve memory, attention, emotion, and executive functions [84][85][86][87][88]. An improvement in local circulation and modulation of Cytochrome C oxidase activity in the discrete parts of the brain, especially the prefrontal cortex, following PBM treatments has been proposed as a potential therapeutic mechanism [89][90][91]. There has been significant progress in our understanding of the molecular mechanisms of PBM in three discrete cellular sites.…”