Effect of transcutaneous electrical acupoint stimulation on learning and memory ability of chronic fatigue syndrome rats and its mechanisms

Abstract:

Objective: To observe the effect of transcutaneous electrical acupoint stimulation (TEAS) on the histomorphological manifestations of hippocampal CA1 region and the expression of extracellular regulatory protein kinase (ERK), cyclic adenosine response element binding protein (CREB) and brain-derived neurotrophic factor (BDNF) in chronic fatigue syndrome (CFS) rats, so as to explore the mechanisms of TEAS in improving the learning and memory abilities of CFS rats.

Methods: Forty male Wistar rats were randomly divided into normal group (10 rats) and modeling group (30 rats); then after modeling, they were selected and randomly divided into model group (10 rats) and TEAS group (10 rats). CFS rats model was prepared by sleep deprivation combined with weight-bearing swimming. Rats in the TEAS group were stimulated with Han’s acupoint nerve stimulator at bilateral “Zusanli” (ST36) and “Shenshu” (BL23) (2 Hz/15 Hz, 1-2 mA), 20 min each time, once a day for 4 weeks with 1 d rest every 6 d. The score of general conditions of rats was evaluated. The learning and memory ability was tested with Morris water maze. The morphology and ultrastructure of hippocampal CA1 region were observed by HE staining and transmission electron microscopy. The expression levels of ERK, CREB and BDNF mRNAs and proteins in hippocampus were detected by real time quantitative PCR and Western blot, respectively.

Results: Compared with the normal group, the score of general condition was increased (P<0.01); the escape latency was prolonged (P<0.05, P<0.01) and the times of crossing the original platform was decreased (P<0.05); the expression levels of ERK, CREB and BDNF mRNAs and proteins in hippocampus were decreased (P<0.05, P<0.01) in the model group. Compared with the model group, the scores of general condition on the 42nd and 49th day were decreased (P<0.05, P<0.01); the escape latency was shortened (P<0.01, P<0.05)and the times of crossing the original platform were increased (P<0.05); the expression levels of ERK, CREB and BDNF mRNAs and proteins in hippocampus were increased (P<0.01, P<0.05) in the TEAS group. The morphology of neurons in hippocampal CA1 region was normal in the normal group. In the model group, the number of neurons in hippocampal CA1 region decreased, the arrangement of nerve cells was scattered, the number of apoptotic cells increased, some nuclear structures disappeared, nuclear heterochromatin increased, the cell membrane wrinkled, the chromatin appeared empty bright area, and the crista was incomplete. Compared with the model group, the nerve cells morphology in hippocampal CA1 region was more regular, the number of apoptotic cells decreased, the chromatin and the cytoplasm were uniformly distributed, and the crista was relatively intact in the TEAS group.

Conclusion: TEAS can improve the learning and memory ability of CFS rats, the mechanisms may be related to improving the neural structure of hippocampal CA1 region and up-regulating the expression levels of ERK/CREB/BDNF.

Source: Zhong XL, Tong BY, Yang YH, Zeng HL, Lin C, Jing Y, He LL, You SJ. [Effect of transcutaneous electrical acupoint stimulation on learning and memory ability of chronic fatigue syndrome rats and its mechanisms]. Zhen Ci Yan Jiu. 2023 Apr 25;48(4):317-24. Chinese. doi: 10.13702/j.1000-0607.20221032. PMID: 37186194. https://pubmed.ncbi.nlm.nih.gov/37186194/

Panax ginseng improves physical recovery and energy utilization on chronic fatigue in rats through the PI3K/AKT/mTOR signalling pathway

Abstract:

Context: Panax ginseng C. A. Meyer (Araliaceae) is a tonic herb used in ancient Asia.

Objective: This study investigated the antifatigue effect of P. ginseng on chronic fatigue rats.

Materials and methods: Sprague-Dawley rats were divided into control, model and EEP (ethanol extraction of P. ginseng roots) (50, 100 and 200 mg/kg) groups (n = 8). The rats were subcutaneously handled with loaded swimming once daily for 26 days, except for the control group. The animals were intragastrically treated with EEP from the 15th day. On day 30, serum, liver and muscles were collected, and the PI3K/Akt/mTOR signalling pathway was evaluated.

Results: The swimming times to exhaust of the rats with EEP were significantly longer than that without it. EEP spared the amount of muscle glycogen, hepatic glycogen and blood sugar under the chronic state. In addition, EEP significantly (p < 0.05) decreased serum triglycerides (1.24 ± 0.17, 1.29 ± 0.04 and 1.20 ± 0.21 vs. 1.58 ± 0.13 mmol/L) and total cholesterol (1.64 ± 0.36, 1.70 ± 0.15 and 1.41 ± 0.19 vs. 2.22 ± 0.19 mmol/L) compared to the model group. Regarding the regulation of energy, EEP had a positive impact on promoting ATPase activities and relative protein expression of the PI3K/Akt/mTOR pathway.

Conclusions: Our results suggested that EEP effectively relieved chronic fatigue, providing evidence that P. ginseng could be a potential dietary supplement to accelerate recovery from fatigue.

Source: Zhang G, Lu B, Wang E, Wang W, Li Z, Jiao L, Li H, Wu W. Panax ginseng improves physical recovery and energy utilization on chronic fatigue in rats through the PI3K/AKT/mTOR signalling pathway. Pharm Biol. 2023 Dec;61(1):316-323. doi: 10.1080/13880209.2023.2169719. PMID: 36695132; PMCID: PMC9879180. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9879180/ (Full text)

Olmesartan alleviates symptoms of chronic fatigue syndrome in mice

Abstract:

Chronic fatigue syndrome (CFS) or myalgic encephalomyelitis (ME) is a lifestyle-related ailment that affects physical and mental abilities.

The etiology is largely unidentified but there are certain multifactorial mechanisms responsible such as mitochondrial aerobic pathways aberrations, hypothalamic-pituitary-adrenal (HPA) axis deregulation, immune hyperactivation, free radicals, pathogen infections, and central neurohumoral alterations.

Olmesartan is an antihypertensive drug that acts on the angiotensin 1 (AT1 ) receptor. The present research evaluated the efficiency of Olmesartanagainst CFS.

CFS was induced by lipopolysaccharide (LPS, 1mg/kg, i.p.) once on day 1 trailed by a forced swim (10 minutes) continued for 21 consecutive times once each day. Olmesartan (1and 3mg/kg, p.o.) and dexamethasone (standard drug, 0.5mg/kg, i.p.) were given from the 1 st to 21 st day.

Immobility time was noted in the forced swim test (FST). Elevated plus maze, raised zero maze, and open field tests were employed to assess animal behavior. Plasma glucose and cortisol, lipid peroxidation, and GSH levels were determined in the whole brain. LPS and repeated forced swim sessions instigated symptoms of CFS such as memory deficit and depression and anxiety-like symptoms.

Findings suggested that Olmesartan shortened the immobility period of mice against CFS in FST. Olmesartan reduced memory deficits, increased ambulation, and exerted an anxiolytic effect. Olmesartan treatment reduced blood cortisol levels, brain TBARS, and enhanced brain GSHin the CFS mouse model.

Hence, Olmesartan may prove to be an effective treatment for CFS and related behavioral discrepancies.

Source:

Electroacupuncture at BL15 attenuates chronic fatigue syndrome by downregulating iNOS/NO signaling in C57BL/6 mice

Abstract:

Chronic fatigue syndrome (CFS) has a high incidence due to the increased pressure of daily life and work in modern society. Our previous clinical studies have found the effects of electroacupuncture (EA) on CFS patients, however, the mechanism of EA on CFS is still unknown. In this study, we investigated the effects of EA on cardiac function in a CFS mouse model to explore its underlying mechanism.

The mice were randomly divided into three groups: control, CFS, and CFS mice receiving EA (CFS + EA). After behavioral assessments and echocardiographic measurement, blood and heart tissue of the mice were collected for biochemical tests, and then we evaluated the effects of EA on the CFS mouse model when nitric oxide (NO) levels were enhanced by l-arginine.

The results showed that EA ameliorated the injured motor and cardiac function. Meanwhile, EA also inhibited increased expression of inducible nitric oxide synthase (iNOS) at heart tissue and the serum NO levels in mice subjected to sustained forced swimming stress. Furthermore, the NO level in serum increased with l-arginine administration, which blocked the effects of EA on CFS mice. This study suggested that EA could improve the motor function and cardiac function in CFS mice and its effects may be associated with the down-regulation of iNOS/NO signaling.

Source: Zhu Y, Wang J, Yao L, Huang Y, Yang H, Yu X, Chen X, Chen Y. Electroacupuncture at BL15 attenuates chronic fatigue syndrome by downregulating iNOS/NO signaling in C57BL/6 mice. Anat Rec (Hoboken). 2022 May 24. doi: 10.1002/ar.24953. Epub ahead of print. PMID: 35608198. https://pubmed.ncbi.nlm.nih.gov/35608198/

Exogenous Transforming Growth Factor-β in Brain-Induced Symptoms of Central Fatigue and Suppressed Dopamine Production in Mice

Abstract:

Myalgic encephalomyelitis (ME)/chronic fatigue syndrome (CFS) is one of the most refractory diseases in humans and is characterized by severe central fatigue accompanied with various symptoms that affect daily life, such as impaired memory, depression, and somatic pain. However, the etiology and pathophysiological mechanisms of CFS remain unknown. To investigate the pathophysiological role of transforming growth factor (TGF)-β1, we injected a cytokine into the lateral ventricle of a C57BL/6 mouse. The intracranial injection of TGF-β1 increased the immobility duration in a forced swimming test (FST) and time spent at the closed arm in elevated plus maze (EPM) analysis.

The mice injected with TGF-β1 into their brain showed increased sensitivity to pain in a von Frey test, and had a decreased retention time on rotarod and latency time in a bright box in a passive avoidance test. In addition, the serum levels of muscle fatigue biomarkers, lactate dehydrogenase (LDH) and creatine kinase (CK), were significantly increased after administration of TGF-β1. Intracranial injection of TGF-β1 significantly reduced the production of tyrosine hydroxylase (TH) in the ventral tegmental area, accompanied by a decreased level of dopamine in the striatum. The suppression of TH expression by TGF-β1 was confirmed in the human neuroblastoma cell line, SH-SY5Y. These results, which show that TGF-β1 induced fatigue-like behaviors by suppressing dopamine production, suggest that TGF-β1 plays a critical role in the development of central fatigue and is, therefore, a potential therapeutic target of the disease.

Source: Lee WK, Kim Y, Jang H, Sim JH, Choi HJ, Shin Y, Choi JJ. Exogenous Transforming Growth Factor-β in Brain-Induced Symptoms of Central Fatigue and Suppressed Dopamine Production in Mice. Int J Mol Sci. 2021 Mar 4;22(5):2580. doi: 10.3390/ijms22052580. PMID: 33806649. https://pubmed.ncbi.nlm.nih.gov/33806649/

Protective Effect of Hemin Against Experimental Chronic Fatigue Syndrome in Mice: Possible Role of Neurotransmitters

Abstract:

Chronic fatigue syndrome (CFS) is a disorder characterized by persistent and relapsing fatigue along with long-lasting and debilitating fatigue, myalgia, cognitive impairment, and many other common symptoms. The present study was conducted to explore the protective effect of hemin on CFS in experimental mice.

Male albino mice were subjected to stress-induced CFS in a forced swimming test apparatus for 21 days. After animals had been subjected to the forced swimming test, hemin (5 and 10 mg/kg; i.p.) and hemin (10 mg/kg) + tin(IV) protoporphyrin (SnPP), a hemeoxygenase-1 (HO-1) enzyme inhibitor, were administered daily for 21 days. Various behavioral tests (immobility period, locomotor activity, grip strength, and anxiety) and estimations of biochemical parameters (lipid peroxidation, nitrite, and GSH), mitochondrial complex dysfunctions (complexes I and II), and neurotransmitters (dopamine, serotonin, and norepinephrine and their metabolites) were subsequently assessed.

Animals exposed to 10 min of forced swimming session for 21 days showed a fatigue-like behavior (as increase in immobility period, decreased grip strength, and anxiety) and biochemical alteration observed by increased oxidative stress, mitochondrial dysfunction, and neurotransmitter level alteration. Treatment with hemin (5 and 10 mg/kg) for 21 days significantly improved the decreased immobility period, increased locomotor activity, and improved anxiety-like behavior, oxidative defense, mitochondrial complex dysfunction, and neurotransmitter level in the brain.

Further, these observations were reversed by SnPP, suggesting that the antifatigue effect of hemin is HO-1 dependent. The present study highlights the protective role of hemin against experimental CFS-induced behavioral, biochemical, and neurotransmitter alterations.

Source: Thakur V, Jamwal S, Kumar M, Rahi V, Kumar P. Protective Effect of Hemin Against Experimental Chronic Fatigue Syndrome in Mice: Possible Role of Neurotransmitters [published online ahead of print, 2020 Jun 6]. Neurotox Res. 2020;10.1007/s12640-020-00231-y. doi:10.1007/s12640-020-00231-y https://link.springer.com/article/10.1007%2Fs12640-020-00231-y

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Induced by Repeated Forced Swimming in Mice

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is characterized by disabling fatigue of at least 6 months, in addition to symptoms such as muscle pain and muscle weakness. There is no treatment provides long-term benefits to most patients. Recently, clinical research suggested the involvement of pyruvate dehydrogenase (PDH) in ME/CFS. PDH is a crucial enzyme in the mitochondria matrix that links glycolysis to the tricarboxylic acid cycle and oxidative phosphorylation. However, it is little known whether PDH could be a therapeutic target. The purpose of this study was to establish ME/CFS in mice and to investigate the involvement of PDH in ME/CFS.

To induce the chronic fatigue in mice, a repeated forced swimming test was conducted. To evaluate fatigue, we measured immobility time in forced swimming test and starting time of grooming. An open field test was conducted on day 8. After 25 d of the forced swimming test, the mitochondrial fraction in gastrocnemius muscle was isolated and PDH activity was measured. Moreover, we evaluated the effect of PDH activation by administering sodium dichloroacetate (DCA).

In ME/CFS mice group, the immobility time and starting time of grooming increased time-dependently. In addition, the moved distance was decreased in ME/CFS mice. PDH activity was decreased in the mitochondrial fraction of the gastrocnemius muscle of the forced swimming group. DCA treatment may be beneficial in preventing fatigue-like behavior in ME/CFS. These findings indicate that ME/CFS model was established in mice and that a decrease in mitochondrial PDH activity is involved with the symptom of ME/CFS.

Source: Ohba T, Domoto S, Tanaka M, Nakamura S, Shimazawa M, Hara H. Biol Pharm Bull. Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Induced by Repeated Forced Swimming in Mice. 2019;42(7):1140-1145. doi: 10.1248/bpb.b19-00009. https://www.jstage.jst.go.jp/article/bpb/42/7/42_b19-00009/_article (Full article)