Electroacupuncture Relieves LPS-Induced Depression-Like Behaviour in Rats Through IDO-Mediated Tryptophan-Degrading Pathway

Abstract

Kun Zhang,1,2 Ran Liu,1,2 Yuan Gao,2 Wen Ma,2 Weidong Shen1,2 1Department of Acupuncture, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai, People’s Republic of China; 2Institute of Acupuncture and Anesthesia, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai, People’s Republic of ChinaCorrespondence: Weidong Shen; Wen MaDepartment of Acupuncture, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, No. 528, Zhang Heng Road, Pu Dong New District, Shanghai 201203, People’s Republic of ChinaTel [phone]; [phone]Fax [phone]Email [email protected]; [email protected]: Neuroinflammation is an important pathological mechanism of depression that leads to an increase in indoleamine-2,3-dioxygenase (IDO) activity and NMDAR activation. This study aimed to observe the effects of electroacupuncture on depression-like behaviour in lipopolysaccharide (LPS)-treated rats and the underlying mechanism.Methods: Wistar rats were intraperitoneally administered LPS (0.5 mg/kg) for 7 consecutive days to establish a depression model. Electroacupuncture treatment was administered 1 hour after daily LPS injection. The open field test (OFT), forced swimming test (FST), and sucrose preference test (SPT) were used to evaluate the depressive-like behaviours. IL-1β, IL-6, and TNF-α levels were determined by enzyme-linked immunosorbent assay (ELISA); Trp, 5-hydroxytryptamine (5-HT), kynurenine (Kyn) and quinolinic acid (Quin) were detected by ultra-high-performance liquid chromatography-tandem mass spectrometry; and N-methyl-D-aspartate receptor (NMDAR) protein and mRNA were assessed by Western blot and real-time qPCR.Results: The results showed that electroacupuncture treatment successfully corrected LPS-induced depressive-like behaviour, reduced the inflammatory factor (IL-1β, IL-6 and TNF-α) levels in the blood and hippocampus, prevented IDO over-activation and recovered NR2B expression after challenge by LPS.Conclusion: Electroacupuncture treatment provided protection against LPS-induced depressive-like behaviour, and the associated mechanisms may be related to inhibiting the inflammatory response, regulating the IDO-mediated tryptophan-degrading pathway, and inhibiting NR2B activation.Keywords: depression, electroacupuncture, LPS, IDO

Keywords

• depression
• electroacupuncture
• lps
• ido.