A study of the effects of photobiomodulation on the elimination of beta‑amyloid and the correction of age‑related cognitive impairments in mice

Abstract

Age is a factor limiting the effectiveness of photobiomodulation (PBM) for brain drainage and cognitive functions. The meningeal lymphatic vessels (MLVs) are “tunnels” for removing toxins from the brain and are a target of PBM. Age‑related decline in the MLV function is one of the mechanisms underlying the reduced stimulating effects of PBM on brain drainage and cognitive processes. During sleep, the brain’s natural drainage is activated. Recent studies have shown that PBM during sleep has a greater impact on the lymphatic clearance of beta‑amyloid and cognitive functions in young and middle‑aged mice. Taking these facts into account, we assumed that PBM would be more effective in old subjects when administered during sleep vs. wakefulness.
The experiments were performed on 24-month-old mice divided into the control, sham, PBM during wakefulness, and PBM during sleep groups (n=8 each). The 10-day course of PBM (1050 nm LED) under EEG-control of sleep and wakefulness was used. Beta-amyloid clearance was assessed via immunohistochemistry, and cognitive function via operant conditioning.
Results demonstrated that only PBM applied during sleep but not wakefulness significantly stimulated lymphatic clearance of beta-amyloid. The formation of conditioned reflexes—assessed by the number of food reinforcements and training sessions (days)—was significantly better in mice receiving the PBS course during sleep than in those receiving it while awake.
Thus, sleep represents a therapeutic window for PBM in aged mice, opening up new prospects for developing pioneering EEG-guided PBM technologies.
This work was supported by the Russian Science Foundation grant No. 25-15-00174 and by the Brain Program of the IDEAS Research Center.

Speaker

Daria Zlatogorskaya
Department of Biology, Saratov State University, Saratov, Russia
Russia

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