Effect of “Tongdu Yupi Tiaoshen” electroacupuncture on behavioral performance and hippocampal structure and function in chronic fatigue syndrome rats

OBJECTIVE: To investigate the effects of electroacupuncture intervention on behavioral performance, hippocampal structure, and function in chronic fatigue syndrome (CFS) rats and to explore the underlying mechanisms. METHODS: Specific pathogen free-grade male Sprague-Dawley rats were randomly allocated into a control group (Con group, n =12) and a modeling group. The latter underwent a 21-d CFS induction viaan improved chronic multi-factor compound stress stimulation protocol. Successfully modeled CFS rats were then randomly assigned to a model group (Mod group, n =12) and an electroacupuncture group (EA group, n =12). During the 14-d treatment period, both the Mod and EA groups continued to receive chronic stress stimuli. Rats in the EA group received electroacupuncture at Shenting (GV24) through to Baihui (GV20), with additional stimulation on Dazhui (GV14). Each session lasted 15 min, administered twice daily with a 6-h interval between morning and afternoon treatments. After modeling and treatment, the general semi-quantitative score (GSQS) was used to evaluate the rats’ general health, while the Morris water maze test (MWMT), open field test (OFT), and exhaustive treadmill test (ETT) were applied to assess their learning/memory, emotional state, and fatigue levels, respectively (n =12 per group). After the treatment phase, cerebral glucose metabolism was assessed by (1);⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) imaging (n =3 per group), while hippocampal cornu ammonis 1 (CA1) morphology was examined using hematoxylin-eosin (HE) and Nissl staining (n =3 per group). RESULTS: Behavioral assessments demonstrated that electroacupuncture intervention significantly improved rat performance as measured by GSQS, MWMT, OFT, and Exhaustive Treadmill Test. Both HE and Nissl staining results confirmed that, compared with the blank control group, the model group exhibited abnormal cellular morphology, disorganized arrangement, and reduced Nissl bodies in the hippocampal CA1 region. These pathological alterations were ameliorated in the electroacupuncture group relative to the model group. 18F-FDG PET/CT imaging revealed that following treatment, the mean and maximum standardized uptake values (SUV) in the anterior-dorsal and posterior hippocampus were significantly decreased in the Mod group compared to the Con group. In contrast, electroacupuncture treatment significantly increased both SUV-mean and SUV-max in these hippocampal subregions in the EA group relative to the Mod group (all P <0.05). CONCLUSION: Electroacupuncture intervention alleviated cognitive impairment, hippocampal pathological structural changes, and glucose metabolism dysfunction in a rat model of chronic fatigue syndrome induced by an improved chronic multi-factor compound stress stimulation method.