Effect of photobiomodulation on the contractility of cervical lymphatic vessels in mice of different ages
Inna A. Blokhina1, Anastasiia D. Kolabukhova1, Anastasiia Semiachkina-Glushkovskaia1, Dmitry V. Tuktarov2 and Nikita A. Navolokin3.
Affiliations:
1 Department of Biology, Saratov State University, Astrakhanskaya 82, 410012 Saratov, Russia.
2 Institute of Physics, Saratov State University, Universitetskaya, 40, 410012 Saratov, Russia.
3 Department of Pathological Anatomy, Saratov State Medical University, Bolshaya Kazachya 112, 410012 Saratov, Russia.
Abstract
The cervical lymphatic vessels (CLVs), which drain the cerebrospinal fluid (CSF) from the brain into the deep cervical lymph nodes, act as “tunnels” for removing metabolites from the central nervous system. The contractility of the lymphatic vessels is an important manifestation of their function, ensuring the movement of lymph through the lymphatic network in order to remove unnecessary compounds, metabolites, and toxins from the tissues. In this aspect, the contractility of CLVs is a key mechanism in the processes of brain drainage and clearance. A decrease in the contractile function of the lymphatic system leads to disruptions in the processes of toxin removal from the brain. Recently, it has been shown that photobiomodulation (PBM) can improve the brain’s lymphatic drainage through the stimulation of nitric oxide (NO) production in the lymphatic endothelium. Based on this fact, it is logical to assume that PBM can also stimulate contractility of CLVs via the NO-mechanism. Therefore, the aim of this study was to investigate the effect of PBM and PBM-mediated NO production on the contractile capacity of CLVs in mice of different ages.
The results revealed that in 3‑ and 12‑month‑old mice, but not in 24‑month‑old animals, PBM increases the contractility of afferent and efferent CLVs. The blockade of NO production in the lymphatic endothelium significantly suppressed the stimulating effect of PBM on the contractile capacity of both types of cervical lymphatic vessels only in 3‑ and 12‑month‑old mice, while 24‑month‑old mice were insensitive to this effect that was accompanied by low basal NO production CLVs in old mice vs. young and middle-age animals.
Overall, PBM exerts a stimulatory effect on the CLV contractility, which is one of the mechanisms underlying the PBM-mediated enhancement of brain drainage and clearance.
The research was supported by the Russian Science Foundation (project No. 24-75-10047).
Speaker
Inna Blokhina
Saratov State University
Russia
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