Beneficial effect of electroacupuncture on the distribution of foreign substances in the brain of rats developing depression-like behavior

Jin-Rong He; Patrizia Rubini; Bao-Man Li; Hai-Yan Yin; Yong Tang; Peter Illes

doi:10.1016/j.ibneur.2023.03.014

Beneficial effect of electroacupuncture on the distribution of foreign substances in the brain of rats developing depression-like behavior

IBRO Neurosci Rep. 2023 Mar 28:14:398-406. doi: 10.1016/j.ibneur.2023.03.014. eCollection 2023 Jun.

Authors

Jin-Rong He¹, Patrizia Rubini^{1

2}, Bao-Man Li³, Hai-Yan Yin¹, Yong Tang^{1

2

4}, Peter Illes^{1

2

5}

Affiliations

¹ School of Acupuncture and Tuina, Chengdu University of Traditional Chinese Medicine, Chengdu 610075, China.
² International Joint Research Centre on Purinergic Signalling of Sichuan Province, Chengdu University of Traditional Chinese Medicine, Chengdu 610075, China.
³ Forensic Analytical Toxicology, School of Forensic Medicine, China Medical University, Shenyang 110177, China.
⁴ Acupuncture and Chronobiology Key Laboratory of Sichuan Province, School of Health and Rehabilitation, Chengdu University of Traditional Chinese Medicine, Chengdu 610075, China.
⁵ Rudolf Boehm Institute for Pharmacology and Toxicology, University of Leipzig, 04109 Leipzig, Germany.

Abstract

We used low and high molecular weight fluorescence tracers to investigate the entry of foreign solutes into the brain parenchyma and their exit from it by the glymphatic system, during experimentally induced depressive-like behavior in rats. The tail suspension test (TST), as an acute stressor, is known to induce such a type of behavior, considered to model the human major depressive disorder (MDD). Electroacupuncture (EAP) relieves both depressive-like behavior in rodents and the symptoms of MDD in humans. Here we report that 180 min after the intracisternal injection of the low molecular weight tracer Fluorescein-5-Isothiocianate Conjugated Dextran (FITC-d3), a 15-min duration TST tended to increase the control fluorescence in the brain of rats. Both EAP and sham EAP decreased the fluorescence of FITC-d3 in comparison with the TST, but not the control value. In addition, EAP and sham EAP counteracted the effects of TST. The high molecular weight tracer Ovalbumin Alexa Fluor 555 Conjugate (OA-45) failed to enter the brain parenchyma and accumulated at more superficial sites; however, EAP or sham EAP modified the distribution of fluorescence under TST application in a similar manner as that observed during the use of FITC-d3. It is concluded that EAP is possibly a valid treatment to slow down the entry of foreign solutes into the brain; in view of the comparable effects of EAP on FITC-d3 and OA-45 distribution, EAP seems to act before FITC-d3 passes the astroglial aquaporin-4 water channels, which are a critical constituent of the glymphatic system.

Keywords: Depression-like behavior; Electroacupuncture; Fluorescence tracers; Glymphatic system; Tail suspension test.