mouse model – Page 4 – American ME and CFS Society

A proprietary herbal drug Young Yum Pill ameliorates chronic fatigue syndrome in mice

Abstract:

Background: Chronic fatigue syndrome (CFS) is a complex disease with few effective and safe therapies. Young Yum Pill (YYP), a proprietary herbal drug, has been used to relieve CFS-like symptoms. The pharmacological basis of this application of YYP is unknown.

Purpose: This study aimed to investigate the pharmacological effects and mechanisms of action of YYP in a mouse model of CFS.

Study design and methods: A food restriction and exhaustive swimming-induced mouse CFS model was used to evaluate the effects of YYP. Lymphocyte proliferation was assessed by MTT assays. T-lymphocyte subsets were analyzed by flow cytometry. Serum biochemical parameters were determined using commercial kits. Protein levels were measured by immunoblotting.

Results: Intragastric administration of YYP (2.85, 5.70, 11.40 g/kg) daily for 21 consecutive days significantly prolonged swimming time and diminished body weight loss of CFS mice. Mechanistic investigations revealed that YYP increased thymus and spleen indices of CFS mice, enhanced proliferation of lipopolysaccharide- or concanavalin A-stimulated spleen lymphocytes, and increased CD3⁺CD4⁺ and CD3⁺CD8⁺ T-cells in the spleen. YYP increased glycogen content in gastrocnemius muscle and liver, and lowered levels of triglyceride, lactic acid and urea nitrogen in sera of CFS mice. YYP suppressed the elevation of serum level of malondialdehyde, the increase of activities of lactic dehydrogenase and creatine phosphokinase, and the decrease of activity of the serum antioxidant enzyme superoxide dismutase in CFS mice. Moreover, YYP upregulated protein level of activated AMPK in gastrocnemius muscle and liver of CFS mice.

Conclusions: YYP ameliorates CFS by reversing metabolic changes, reducing oxidative damage, and improving some immune function parameters in mice. This study provides pharmacological justifications for the use of YYP in treating fatigue, including CFS.

Source: Yin C, Fu X, Chou J, Li J, Chen Y, Bai J, Wu J, Wu Y, Wang X, Yu ZL. A proprietary herbal drug Young Yum Pill ameliorates chronic fatigue syndrome in mice. Phytomedicine. 2021 May 25;88:153602. doi: 10.1016/j.phymed.2021.153602. Epub ahead of print. PMID: 34102522. https://pubmed.ncbi.nlm.nih.gov/34102522/

Local immune response to food antigens drives meal-induced abdominal pain

Abstract:

Up to 20% of people worldwide develop gastrointestinal symptoms following a meal1, leading to decreased quality of life, substantial morbidity and high medical costs. Although the interest of both the scientific and lay communities in this issue has increased markedly in recent years, with the worldwide introduction of gluten-free and other diets, the underlying mechanisms of food-induced abdominal complaints remain largely unknown. Here we show that a bacterial infection and bacterial toxins can trigger an immune response that leads to the production of dietary-antigen-specific IgE antibodies in mice, which are limited to the intestine.

Following subsequent oral ingestion of the respective dietary antigen, an IgE- and mast-cell-dependent mechanism induced increased visceral pain. This aberrant pain signalling resulted from histamine receptor H1-mediated sensitization of visceral afferents. Moreover, injection of food antigens (gluten, wheat, soy and milk) into the rectosigmoid mucosa of patients with irritable bowel syndrome induced local oedema and mast cell activation. Our results identify and characterize a peripheral mechanism that underlies food-induced abdominal pain, thereby creating new possibilities for the treatment of irritable bowel syndrome and related abdominal pain disorders.

Source: Aguilera-Lizarraga, J., Florens, M.V., Viola, M.F. et al. Local immune response to food antigens drives meal-induced abdominal pain. Nature (2021). https://doi.org/10.1038/s41586-020-03118-2 https://www.nature.com/articles/s41586-020-03118-2#Abs1

Oxidative stress caused by a dysregulated Wnt/β-catenin signalling pathway is involved in abnormal placenta formation in pregnant mice with chronic fatigue syndrome

Abstract:

Chronic fatigue syndrome (CFS) is characterized by extreme fatigue and disabling symptoms. Women with CFS often have a high risk of gynaecological problems such as irregular menstruation, endometriosis and pelvic pain and sexual dysfunction. Our previous results have shown that, in pregnant mice, CFS significantly decreased the progestational hormone level in serum, as well as learning and memory, and the function of the hypothalamus-pituitary-gonadal axis. In addition, the F1 generation also suffered from congenital hypothyroidism. At present, there has been no report about placenta formation and embryonic development in pregnant mice with CFS. The aim of the present study was to investigate the influence of CFS on the morphology, oxidative stress and Wnt/β-catenin signalling pathway during placenta formation.

In this study, we found that CFS decreased the number of implantation sites for blastocysts, and increased the number of absorbed, stillborn and malformed fetuses. The morphology and structure of the placenta were abnormal in pregnant mice with CFS. Further study found that the oxidative stress in serum, uterus and placenta was increased in pregnant mice with CFS, while the levels of antioxidase were decreased. CFS also inhibited the Wnt/β-catenin signalling pathway in the placenta. These results suggested that inhibition of the Wnt/β-catenin signalling pathway and enhanced oxidative stress play an important role in abnormal placentation in pregnant mice with CFS.

Source: Zhao H, Zhang J, Qian N, Wu S, Wu Y, Yao G. Oxidative stress caused by a dysregulated Wnt/β-catenin signalling pathway is involved in abnormal placenta formation in pregnant mice with chronic fatigue syndrome. Zygote. 2020 Oct 15:1-8. doi: 10.1017/S096719942000057X. Epub ahead of print. PMID: 33054899. https://pubmed.ncbi.nlm.nih.gov/33054899/

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

An Adrenalectomy Mouse Model Reflecting Clinical Features for Chronic Fatigue Syndrome

Abstract:

Chronic fatigue syndrome (CFS) is one of the most intractable diseases and is characterized by severe central fatigue that impairs even daily activity. To date, the pathophysiological mechanisms are uncertain and no therapies exist. Therefore, a proper animal model reflecting the clinical features of CFS is urgently required.

We compared two CFS animal models most commonly used, by injection with lipopolysaccharide (LPS from Escherichia coli O111:B4) or polyinosinic: polycytidylic acid (poly I:C), along with bilateral adrenalectomy (ADX) as another possible model. Both LPS- and poly I:C-injected mice dominantly showed depressive behaviors, while ADX led to fatigue-like performances with high pain sensitivity.

In brain tissues, LPS injection notably activated microglia and the 5-hydroxytryptamine (HT)1A receptor in the prefrontal cortex and hippocampus. Poly I:C-injection also remarkably activated the 5-HT transporter and 5-HT1A receptor with a reduction in serotonin levels in the brain. ADX particularly activated astrocytes and transforming growth factor beta (TGF-β) 1 in all brain regions.

Our results revealed that LPS and poly I:C animal models approximate depressive disorder more closely than CFS. We suggest that ADX is a possible method for establishing a mouse model of CFS reflecting clinical features, especially in neuroendocrine system.

Source: Lee JS, Jeon YJ, Park SY, Son CG. An Adrenalectomy Mouse Model Reflecting Clinical Features for Chronic Fatigue Syndrome. Biomolecules. 2020 Jan 1;10(1). pii: E71. doi: 10.3390/biom10010071. https://www.mdpi.com/2218-273X/10/1/71 (Full article)

Neuroinflammation, Oxidative Stress, and Neurogenesis in a Mouse Model of Chronic Fatigue Syndrome, and the Treatment with Kampo Medicine

Abstract:

The diagnosis of chronic fatigue syndrome (CFS) is mainly symptom-based, and the etiology is still unclear. Here, we evaluated the pathological changes in the brain of a mouse model of CFS and studied the effects of Kampo medicine.

A mouse model of CFS was established through six repeated injections of Brucella abortus (BA) every two weeks for a period of 12 weeks. Neuroinflammation was measured by estimating interleukin (IL)-1β, IL-6, and interferon-gamma (IFN-γ), and oxidative stress by nitrotyrosine (3-NT) and 4-hydroxynonenal (4-HNE) 6 weeks after the last injection. Hippocampal neurogenesis was evaluated through Ki-67, doublecortin (DCX), and 5-bromodeoxyuridine (BrdU) assays. The effects of Kampo medicines (Hochuekkito (TJ-41) and Hachimijiogan (TJ-7)) on neuroinflammation during CFS were studied.

The wheel-running activity of mice was decreased by about 50% compared to baseline at 6 weeks after the last BA injection. The levels of IL-1β, IL-6, 3-NT, and 4-HNE were increased in both the cortex and the hippocampus of CFS mice at 6 weeks after the last BA injection. Hippocampal neurogenesis was unchanged in CFS mice. Treatment with TJ-41 and TJ-7 reduced the expressions of IL-1β, IL-6, and IFN-γ in the hippocampus but not in the cortex.

The results of the present study indicate that neuroinflammation and oxidative stress play important roles in the pathogenesis of CFS. The data further suggest that treatment with TJ-41 and TJ-7 could help reduce the inflammation associated with CFS in the hippocampus, but failed to improve the symptoms in CFS mice.

Source: He Q, Sawada M, Yamasaki N, Akazawa S, Furuta H, Uenishi H, Meng X, Nakahashi T, Ishigaki Y, Moriya J. Neuroinflammation, Oxidative Stress, and Neurogenesis in a Mouse Model of Chronic Fatigue Syndrome, and the Treatment with Kampo Medicine. Biol Pharm Bull. 2020;43(1):110-115. doi: 10.1248/bpb.b19-00616. https://www.jstage.jst.go.jp/article/bpb/43/1/43_b19-00616/_article (Full article)

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)

NLRP3 inflammasome activation mediates fatigue-like behaviours in mice via neuroinflammation

Abstract:

Numerous experimental and clinical studies have suggested that the interaction between the immune system and the brain plays an important role in the pathophysiology of chronic fatigue syndrome (CFS). The NLRP3 inflammasome is an important part of the innate immune system. This complex regulates proinflammatory cytokine interleukin-1β (IL-1β) maturation, which triggers different kinds of immune-inflammatory reactions.

We employed repeated forced swims to establish a model of CFS in mice. NLRP3 knockout (KO) mice were also used to explore NLRP3 inflammasome activation in the mechanisms of CFS, using the same treatment. After completing repeated swim tests, the mice displayed fatigue-like behaviours, including locomotor activity and reduced fall-off time on the rota-rod test, which was accompanied by significantly higher mature IL-1β level in the prefrontal cortex (PFC) and malondialdehyde (MDA) level in serum. We also found increased NLRP3 protein expression, NLRP3 inflammasome formation and increased mature IL-1β production in the PFC, relative to untreated mice. The NLRP3 KO mice displayed significantly moderated fatigue behaviours along with decreased PFC and serum IL-1β levels under the same treatment.

These findings demonstrated the involvement of NLRP3 inflammasome activation in the mechanism of swimming-induced fatigue. Future therapies targeting the NLRP3/IL-1β pathway may have significant potential for fatigue prevention and treatment.

Source: Zhang Z, Ma X, Xia Z, Chen J, Liu Y, Chen Y, Zhu J, Li J, Yu H, Zong Y, Lu G. NLRP3 inflammasome activation mediates fatigue-like behaviours in mice via neuroinflammation. Neuroscience. 2017 Jul 3. pii: S0306-4522(17)30453-0. doi: 10.1016/j.neuroscience.2017.06.048. [Epub ahead of print] https://www.ncbi.nlm.nih.gov/pubmed/28684277

Activation of the NLRP3 inflammasome in lipopolysaccharide-induced mouse fatigue and its relevance to chronic fatigue syndrome

Abstract:

BACKGROUND: The NLRP3 inflammasome (NOD-like receptor family, pyrin domain containing 3) is an intracellular protein complex that plays an important role in innate immune sensing. Its activation leads to the maturation of caspase-1 and regulates the cleavage of interleukin (IL)-1β and IL-18. Various studies have shown that activation of the immune system plays a pivotal role in the development of fatigue. However, the mechanisms underlying the association between immune activation and fatigue remained elusive, and few reports have described the involvement of NLRP3 inflammasome activation in fatigue.

METHODS: We established a mouse fatigue model with lipopolysaccharide (LPS, 3 mg/kg) challenge combined with swim stress. Both behavioural and biochemical parameters were measured to illustrate the characteristics of this model. We also assessed NLRP3 inflammasome activation in the mouse diencephalon, which is the brain region that has been suggested to be responsible for fatigue sensation. To further identify the role of NLRP3 inflammasome activation in the pathogenesis of chronic fatigue syndrome (CFS), NLRP3 KO mice were also subjected to LPS treatment and swim stress, and the same parameters were evaluated.

RESULTS: Mice challenged with LPS and subjected to the swim stress test showed decreased locomotor activity, decreased fall-off time in a rota-rod test and increased serum levels of IL-1β and IL-6 compared with untreated mice. Serum levels of lactic acid and malondialdehyde (MDA) were not significantly altered in the treated mice. We demonstrated increased NLRP3 expression, IL-1β production and caspase-1 activation in the diencephalons of the treated mice. In NLRP3 KO mice, we found remarkably increased locomotor activity with longer fall-off times and decreased serum IL-1β levels compared with those of wild-type (WT) mice after LPS challenge and the swim stress test. IL-1β levels in the diencephalon were also significantly decreased in the NLRP3 KO mice. By contrast, IL-6 levels were not significantly altered.

CONCLUSIONS: These findings suggest that LPS-induced fatigue is an IL-1β-dependent process and that the NLRP3/caspase-1 pathway is involved in the mechanisms of LPS-induced fatigue behaviours. NLRP3/caspase-1 inhibition may be a promising therapy for fatigue treatment.

Source: Zhang ZT, Du XM, Ma XJ, Zong Y, Chen JK, Yu CL, Liu YG, Chen YC, Zhao LJ, Lu GC. Activation of the NLRP3 inflammasome in lipopolysaccharide-induced mouse fatigue and its relevance to chronic fatigue syndrome. J Neuroinflammation. 2016 Apr 5;13(1):71. doi: 10.1186/s12974-016-0539-1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4822300/ (Full article)

Evaluation of the effect of ethanolic extract of fruit pulp of Cassia fistula Linn. on forced swimming induced chronic fatigue syndrome in mice

Abstract:

The fruit of Cassia fistula Linn. is a legume, has antioxidant and lots of other medicinal properties. As oxidants are involved in the pathogenesis of chronic fatigue syndrome, the present study was done to evaluate the effect of ethanolic extract of fruit pulp of C. fistula Linn. (EECF) on forced swimming induced chronic fatigue syndrome (CFS).

Albino mice of 25-40 grams were grouped into five groups (n=5). Group A served as naive control and group B served as stress control. Group C received EECF 200 mg/kg and group D received EECF 400 mg/kg respectively. Group E received imipramine 20 mg/kg (standard). All animals were treated with their respective agent orally daily for 7 days. Except for group A, animals in other groups were subjected to force swimming 6 min daily for 7 days to induce a state of chronic fatigue. Duration of immobility was assessed on day 1(st), 3(rd), 5(th) and 7(th). Anxiety level (by elevated plus maze and mirrored chamber) and loco-motor activity (by open field test) were assessed 24 h after last force swimming followed by biochemical estimations of oxidative biomarkers in brain homogenate at the end of study.

Treatment with EECF resulted in significant reduction in the duration of immobility, reduced anxiety and increased loco-motor activity. Malondialdehyde level was also reduced and catalase level was increased in the extract treated group and standard group compared to stress control group. The study indicates that EECF has protective effect against experimentally induced CFS.

Source: Sarma P, Borah M, Das S. Evaluation of the effect of ethanolic extract of fruit pulp of Cassia fistula Linn. on forced swimming induced chronic fatigue syndrome in mice. Res Pharm Sci. 2015 May-Jun;10(3):206-13. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4621627/ (Full article)