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

Abstract

Background: 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 depressionlike 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 LPSinduced 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.

Electroacupuncture Ameliorates Depression-Like Behaviour in Rats by Enhancing Synaptic Plasticity via the GluN2B/CaMKII/CREB Signalling Pathway

“…Consistently, our results showed that, after 28 days of CUMS induction, the rats exhibited significantly reduced sucrose consumption, significantly lower numbers of crossings, and significantly increased immobility times in the FST, whereas EA reversed these changes and exerted effects similar to those obtained with FLX. This finding shows that EA exerts a good antidepressant effect, which is consistent with some of our previous research results [ 33 , 40 ].…”

“…The rats were first fixed on a special fixator, and acupuncture needles (0.22 mm × 25 mm, Huan-Qiu, Suzhou Huanqiu Medical Appliance Co., Ltd., China) were inserted into the GV20 and GV29 acupoints ( Figure 2 ) at depths of 7 mm and 4 mm and connected to an electroacupuncture apparatus (Hwato SDZ-V, Suzhou Medical Supplies, China). The parameters of the electroacupuncture apparatus were determined according to our previous research [ 33 ]. Specifically, the waveform was an intermittent wave, the frequency was 2 Hz, and each EA treatment lasted for 20 min.…”

“…The forced swim test (FST) was performed as previously reported [ 33 ]. The rats were placed in a bucket (height of 50 cm × diameter of 25 cm) with a water depth of 35 cm (20–22°C) and allowed to swim for 6 min.…”

“…e parameters of the electroacupuncture apparatus were determined according to our previous research [33]. Specifically, the waveform was an intermittent wave, the frequency was 2 Hz, and each EA treatment lasted for 20 min.…”

Antidepressant effect of electroacupuncture on modulating the expression of c‐Fos/AP‐1 through the JNK signaling pathway

“…The results of this study are consistent with previous studies, indicating that CUMS can induce depression-like behaviors and can effectively mimic the symptoms of patients with depression (Höflich, Michenthaler, Kasper, & Lanzenberger, 2019;Jiang et al, 2017;Watson, Harvey, McCabe, & Reynolds, 2020). Meanwhile, EA significantly ameliorated the CUMS-induced depression-like behaviors and exerted an obvious antidepressant effect, which is consistent with the previous studies Zhang, Liu, Gao, Ma, & Shen, 2020). Acupuncture, one of the conventional therapies in TCM, exerts therapeutic effects via modulating the nervous, endocrine, and immune systems (Zhou & Benharash, 2014).…”