This research was supported by a grant from the Russian Science Foundation (No. 23-75-30001).

All procedures were performed in accordance with the &#34;Guide for the Care and Use of Laboratory Animals&#34;, Directive 2010/63/EU on the Protection of Animals Used for Scientific Purposes, and the guidelines from the Ministry of Science and High Education of the Russian Federation (N&#186; 742 from 13.11.1984), which have been approved by the Bioethics Commission of the Saratov State University (Protocol No. 7, 22.09.2022).
1. Hardware assembly
<ol>
	<li>Cut a piece of f...

Enhancing Brain Drainage During Sleep with Transcranial Photobiomodulation

MLVs are an important target for the development of innovative technologies for modulation of the brain&#39;s drainage and removal of cellular debris and wastes from the brain, especially in aged subjects whose MLV function declines1,22. In a homeostatic state, deep sleep is associated with the natural activation of brain tissue cleansing13,14. Therefore, it is obvious to expect that stimulation of MLVs d...

Meningeal lymphatic vessels (MLVs) play an important role in the removal of toxins and metabolites from brain tissues1,2,3. Damage of MLVs in various brain diseases, including tumors, traumatic brain injuries, hemorrhages, and neurodegenerative processes, is accompanied by a decrease in the MLV functions leading to the progression of these pathologies1,2,3,4,5,6. Therefore, the development of methods for the stimulation of MLVs opens new horizons in the emergence of effective technologies for the treatment of brain diseases. Recently, non-invasive technology for effective transcranial photobiomodulation (tPBM) has been proposed to stimulate MLVs and remove toxins such as blood and A&#946; from the brain5,7,8,9,10,11,12. It is interesting to note that deep sleep is a natural factor for the activation of lymphatic drainage processes in the brain13,14. Based on this fact, it is logical to assume that the tPBM of MLVs during sleep may have more effective therapeutic effects than during wakefulness9,11,12,15. However, there are currently no commercial technologies for tPBM during sleep16. In addition, animal experiments to study the therapeutic effects of tPBM are performed under anesthesia, which is required to accurately deliver light to the brain. However, anesthesia significantly affects the brain&#39;s drainage, which reduces the quality of research results17.
A&#946; is a metabolic product of normal neural activity18. As it was established in cultured rat cortical neurons, A&#946; is released from them at high rates into the extracellular space (2-4 molecules/neuron/s for A&#946;)19. There is evidence that the dissolved form of A&#946;, located in the extracellular and perivascular spaces, is most toxic to neurons and synapses20. The soluble A&#946; is rapidly cleared from the human brain during 1-2.5 h21. MLVs are the tunnels for removal of the soluble A&#946; from the brain1,7 that declines with age, leading to the accumulation of A&#946; in the aged brain1,22. There is evidence that extracellular abnormalities of A&#946; levels in the brain correlate with cognitive performance in aging and are associated with the development of Alzheimer&#39;s disease (AD)23,24. Therefore, aged and old rodents are considered alternatives to transgenic models for the study of amyloidosis, including AD25,26.
This study presents an original and portable tPBM technology under electroencephalographic (EEG) control of deep or non-rapid eye movement (NREM) sleep in non-anesthetized male BALB/c mice of different ages to stimulate lymphatic clearance of A&#946; from the brain into the peripheral lymphatic system (the deep cervical lymph nodes, dcLNs).

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			<td>0.1% Tween20</td>
			<td>Helicon,&#160; Russia</td>
			<td>SB-G2009-100ML</td>
			<td></td>
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		<tr>
			<td>Catheter</td>
			<td>Scientific Commodities Inc., USA</td>
			<td>PE-10, 0.28 mm ID &#215; 0.61 mm OD</td>
			<td></td>
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			<td>CO2 chamber</td>
			<td>Binder, Germany</td>
			<td>CB-S 170</td>
			<td></td>
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			<td>Confocal microscop</td>
			<td>Nikon, Japan</td>
			<td>A1R MP</td>
			<td></td>
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			<td>Dental acrylic</td>
			<td>Zermack, Poland-Russia</td>
			<td>Villacryl S, V130V4Z05</td>
			<td></td>
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		<tr>
			<td>Drill</td>
			<td>Foredom, Russia</td>
			<td>SR W-0016</td>
			<td></td>
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			<td>Dumont forceps</td>
			<td>Stoelting, USA</td>
			<td>52100-07</td>
			<td></td>
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		<tr>
			<td>Evans Blue dye</td>
			<td>Sigma-Aldrich, St. Louis, MO, USA</td>
			<td>206334</td>
			<td></td>
		</tr>
		<tr>
			<td>Hamilton</td>
			<td>Hamilton Bonaduz AG, Switzerland</td>
			<td>29 G needle</td>
			<td></td>
		</tr>
		<tr>
			<td>Ibuprofen</td>
			<td>Sintez OJSC, Russia</td>
			<td>N/A</td>
			<td>&#160;Analgesic drug</td>
		</tr>
		<tr>
			<td>Insulin needle</td>
			<td>INSUPEN, Italy</td>
			<td>31 G, 0.25 mm x 6 mm</td>
			<td></td>
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			<td>Micro forceps</td>
			<td>Stoelting, USA</td>
			<td>52102-02P</td>
			<td></td>
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			<td>Microcentrifuge</td>
			<td>Gyrozen, South Korea</td>
			<td>GZ-1312</td>
			<td></td>
		</tr>
		<tr>
			<td>Microinjector</td>
			<td>Stoelting, USA</td>
			<td>53311</td>
			<td></td>
		</tr>
		<tr>
			<td>Non-sharp tweezer</td>
			<td>Stoelting, USA</td>
			<td>52108-83P</td>
			<td></td>
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		<tr>
			<td>PINNACLE system</td>
			<td>Pinnacle Technology, USA</td>
			<td>8400-K3-SL</td>
			<td>System for recording EEG (2 channels) and EMG (1 channel) of mice</td>
		</tr>
		<tr>
			<td>Shaving machine</td>
			<td>Braun</td>
			<td>Series 3310s</td>
			<td></td>
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		<tr>
			<td>Single and multi-channel pipettes</td>
			<td>Eppendorf, Austria</td>
			<td>Epp 3120 000.020, Epp 3122 000.019</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium chloride</td>
			<td>Kraspharma, Russia</td>
			<td>N/A</td>
			<td></td>
		</tr>
		<tr>
			<td>Soldering station</td>
			<td>AOYUE, China</td>
			<td>N/A</td>
			<td></td>
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			<td>Stereotaxic frame</td>
			<td>Stoelting, USA</td>
			<td>51500</td>
			<td></td>
		</tr>
		<tr>
			<td>Straight dissecting scissors</td>
			<td>Stoelting, USA</td>
			<td>52132-10P</td>
			<td></td>
		</tr>
		<tr>
			<td>Tetracycline</td>
			<td>JSC Tatkhimfarmpreparaty, Russia</td>
			<td>N/A</td>
			<td>Eye ointment</td>
		</tr>
		<tr>
			<td>Tweezer</td>
			<td>Stoelting, USA</td>
			<td>52100-03</td>
			<td></td>
		</tr>
		<tr>
			<td>Ultrasonic cell disrupter</td>
			<td>Biobase, China</td>
			<td>USD-500</td>
			<td></td>
		</tr>
		<tr>
			<td>Wound retractor</td>
			<td>Stoelting, USA</td>
			<td>52125</td>
			<td></td>
		</tr>
		<tr>
			<td>Xylanit</td>
			<td>Nita-Farm, Russia</td>
			<td>N/A</td>
			<td>Muscle relaxant</td>
		</tr>
		<tr>
			<td>Zoletil 100</td>
			<td>Virbac Sante Animale, France</td>
			<td>N/A</td>
			<td>General anesthesia</td>
		</tr>
	</tbody>
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photobiomodulation under electroencephalographic controls of sleep for stimulation of lymphatic removal of toxins from mouse brain

The meningeal lymphatic vessels (MLVs) play an important role in the removal of toxins from the brain. The development of innovative technologies for the stimulation of MLV functions is a promising direction in the progress of the treatment of various brain diseases associated with MLV abnormalities, including Alzheimer&#39;s and Parkinson&#39;s diseases, brain tumors, traumatic brain injuries, and intracranial hemorrhages. Sleep is a natural state when the brain&#39;s drainage processes are most active. Therefore, stimulation of the brain&#39;s drainage and MLVs during sleep may have the most pronounced therapeutic effects. However, such commercial technologies do not currently exist.
This study presents a new portable technology of transcranial photobiomodulation (tPBM) under electroencephalographic (EEG) control of sleep designed to photo-stimulate removal of toxins (e.g., soluble amyloid beta (A&#946;)) from the brain of aged BALB/c mice with the ability to compare the therapeutic effectiveness of different optical resources. The technology can be used in the natural condition of a home cage without anesthesia, maintaining the motor activity of mice. These data open up new prospects for developing non-invasive and clinically promising photo-technologies for the correction of age-related changes in the MLV functions and brain&#39;s drainage processes and for effectively cleansing brain tissues from metabolites and toxins. This technology is intended both for preclinical studies of the functions of the sleeping brain and for developing clinically relevant treatments for sleep-related brain diseases.

Author Spotlight: Developing Photo-Stimulation Technology for Toxin Removal in Sleep-Related Brain Diseases

Photobiomodulation Under Electroencephalographic Controls of Sleep for Stimulation of Lymphatic Removal of Toxins from Mouse Brain

In the first step, the study has focused on establishing the effective light dose (a 1050 nm LED) for stimulation of lymphatic removal of fluorescent A&#946; from the brain to dcLNs in awake adult (2-3 month old, 26-29 g) male BALB/c mice. The light doses were selected randomly as 10 J/cm2, 20 J/cm2, and 30 J/cm2 based on our previous studies of tPBM effects on the removal of different dyes and the red blood cells from the brain7,<sup class="x...

This study presents the non-invasive and portable technology of transcranial photobiomodulation under electroencephalographic control for stimulation lymphatic removal of toxins (e.g., soluble amyloid beta) from the brain of aged and non-anesthetized BALB/c male mice during natural deep sleep.

The meningeal lymphatic vessels (MLVs) play an important role in the removal of toxins from the brain. The development of innovative technologies for the ...