Involvement of the astroglial glutamate–glutamine cycle in the analgesic effects of electroacupuncture in a rat model of chronic neuropathic pain
Year: 2024
Type: article
Abstract: OBJECTIVE: Our previous study found that astrocytes are involved in cumulative analgesia; however, the underlying mechanism remains unclear. The aim of this study was to further explore the potential role of astrocytes in the effects of electroacupuncture (EA) on neuropathic pain by focusing on the glutamate-glutamine cycle. METHODS: 69 male Sprague-Dawley (SD) rats were randomly divided into a normal control group, untreated chronic constriction injury (CCI) model group and EA-treated model (CCI + EA) group. EA was applied bilaterally at ST36 and GB34. Pain thresholds were assessed using behavioral tests and thermal stimuli. We examined the co-expression of glutamate/aspartate transporter (GLAST) via immunofluorescence and measured the expression levels of GLAST, glutamate transporter (GLT)-1 and glutamine synthetase (GS) using Western blotting and polymerase chain reaction (PCR). Glutamate (Glu) and gamma-aminobutyric acid (GABA) levels were detected by high-performance liquid chromatography (HPLC). To validate the impact of GLAST/GLT-1 in the analgesic effect of EA, an additional 30 SD male rats were divided into groups receiving intrathecal saline, GLAST antagonist or GLT-1 antagonist alongside EA. RESULTS: Post-CCI, pain thresholds were decreased, GLAST expression was diminished, and spinal Glu levels were increased. EA treatment reversed these effects, improved pain thresholds and GLAST/GLT-1 expression in astrocytes, and reduced Glu levels. Antagonist administration negated the analgesic effects of EA. CONCLUSION: Repeated EA administration inhibited CCI-induced chronic neuropathic pain in rats, corresponding to a reversal of decreased expression of GLAST and GLT-1, which may have accelerated the clearance of Glu and thereby reduced its concentration. Regulation of the astroglial glutamate-glutamine cycle is a potential target of EA.
Source: Acupuncture in Medicine
Authors: Hao-Han Zhu, Xing-Ke Song, Jian-Liang Zhang, Jin-Ling Zhang, Pei-Jing Rong, Jun-Ying Wang
Institution: China Academy of Chinese Medical Sciences
Language: English
Subfield: Physiology
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W4405917747