Neuroprotective Effects against POCD by Photobiomodulation: Evidence from Assembly/Disassembly of the Cytoskeleton

Abstract

Postoperative cognitive dysfunction (POCD) is a decline in memory following anaesthesia and surgery in elderly patients. While often reversible, it consumes medical resources, compromises patient well-being, and possibly accelerates progression into Alzheimer’s disease. Anesthetics have been implicated in POCD, as has neuroinflammation, as indicated by cytokine inflammatory markers. Photobiomodulation (PBM) is an effective treatment for a number of conditions, including inflammation. PBM also has a direct effect on microtubule disassembly in neurons with the formation of small, reversible varicosities, which cause neural blockade and alleviation of pain symptoms. This mimics endogenously formed varicosities that are neuroprotective against damage, toxins, and the formation of larger, destructive varicosities and focal swellings. It is proposed that PBM may be effective as a preconditioning treatment against POCD; similar to the PBM treatment, protective and abscopal effects that have been demonstrated in experimental models of macular degeneration, neurological, and cardiac conditions.

Anesthesia and cognitive disorders: a systematic review of the clinical evidence

“…It involves the deposition of the extracellular aggregates of β-amyloid, known as senile plaques, and the formation of neurofibrillary tangles that are intracellular inclusions mainly composed of hyperphosporylated tau [4]. POCD is a decline in memory following anesthesia and surgery and The risk factors of developing POCD mainly include larger and more invasive operations, duration of anesthesia, advanced age and other factors [5,6].…”

Low‐Intensity Photobiomodulation Decreases Neuropathic Pain in Paw Ischemia‐Reperfusion and Spared Nervus Ischiadicus Injury Experimental Models

“…Recent researches support the ability of light to penetrate the brain tissue and exert biological effects on photoacceptor molecules present in central nervous system structures . Several studies have shown its potential benefits in retinal diseases, stroke, neurodegeneration, neuromuscular disorders, and memory and mood disorders . In addition, the increase of the pain threshold in the right hindpaw of mice (measured by von Frey filaments) was demonstrated after photobiomodulation with infrared (810 nm) applied to different anatomical locations.…”

Six Years Follow-Up of Low-Level Laser Therapy (Lllt) in Patients With Age-Related Macular Degeneration (Amd).

“…Potent neuroprotective effects have been demonstrated in various models of retinal damage, by red -633/NIR light, with limited data from human studies showing its ability to improve visual function. Improved neuronal mitochondrial function, increased blood flow to neural tissue, upregulation of cell survival mediators and restoration of normal microglial function have all been proposed as potential underlying mechanisms of red/NIR light[ [16,17].…”

“…Local helium-neon laser therapy contributes to the prevention of the inflammatory reaction and promotes local tissue proliferation and wound healing [13] LLLT is a special type of laser therapy in which the irradiation used is red or near infrared beams with a wavelength of 600 -1100 nm and an output power of 1 -500 mW. This type of radiation is a continuous wave or pulsed light which consists of a constant beam of relatively low energy density (0.04-50 J/cm 2 ) [14,15,16,17]. LLLT represents a novel therapeutic method that, other than surgical laser applications, does not damage tissues [18.19].…”