Impact of high intensity exercise on muscle morphology in EAE rats

Effects of Turmeric Extract on Age-Related Skeletal Muscle Atrophy in Senescence-Accelerated Mice

Muscle atrophy is one of the main causes of sarcopenia—the age-related loss of skeletal muscle. In this study, we investigated the effect of turmeric (Curcuma longa) extract (TE) supplementation on age-related muscle atrophy in a senescence-accelerated mouse model and explored the underlying mechanisms. Twenty-six-week-old male, senescence-accelerated mouse resistant (SAMR) mice received the AIN-93G basal diet, while twenty-six-week-old male, senescence-accelerated mouse prone 8 (SAMP8) mice received the AIN-93G basal diet or a 2% TE powder-supplemented diet for ten weeks. Our findings revealed that TE supplementation showed certain effects on ameliorating the decrease in body weight, tibialis anterior weight, and mesenteric fat tissue weight in SAMP8 mice. TE improved gene expression in the glucocorticoid receptor-FoxO signaling pathway in skeletal muscle, including redd1, klf15, foxo1, murf1, and mafbx. Furthermore, TE might have the certain potential on improving the dynamic balance between anabolic and catabolic processes by inhibiting the binding of glucocorticoid receptor or FoxO1 to the glucocorticoid response element or FoxO-binding element in the MuRF1 promoter in skeletal muscle, thereby promoting muscle mass and strength, and preventing muscle atrophy and sarcopenia prevention. Moreover, TE may have reduced mitochondrial damage and maintained cell growth and division by downregulating the mRNA expression of the genes mfn2 and tsc2. Thus, the results indicated TE’s potential for preventing age-related muscle atrophy and sarcopenia.

Effectiveness of exercise interventions in animal models of multiple sclerosis

Multiple sclerosis (MS) is associated with an impaired immune system that severely affects the spinal cord and brain, and which is marked by progressive inflammatory demyelination. Patients with MS may benefit from exercise training as a suggested course of treatment. The most commonly used animal models of studies on MS are experimental autoimmune/allergic encephalomyelitis (EAE) models. The present review intends to concisely discuss the interventions using EAE models to understand the effectiveness of exercise as treatment for MS patients and thereby provide clear perspective for future research and MS management. For the present literature review, relevant published articles on EAE animal models that reported the impacts of exercise on MS, were extracted from various databases. Existing literature support the concept that an exercise regimen can reduce the severity of some of the clinical manifestations of EAE, including neurological signs, motor function, pain, and cognitive deficits. Further results demonstrate the mechanisms of EAE suppression with information relating to the immune system, demyelination, regeneration, and exercise in EAE. The role for neurotrophic factors has also been investigated. Analyzing the existing reports, this literature review infers that EAE is a suitable animal model that can help researchers develop further understanding and treatments for MS. Besides, findings from previous animal studies supports the contention that exercise assists in ameliorating MS progression.

Exercise training alters autoimmune cell invasion into the brain in autoimmune encephalomyelitis

BACKGROUND

The mechanisms by which exercise training (ET) elicits beneficial effects on the systemic immune system and the central nervous system (CNS) in autoimmune neuroinflammation are not fully understood.

OBJECTIVES

To investigate (1) the systemic effects of high-intensity continuous training (HICT) on the migratory potential of autoimmune cells; (2) the direct effects of HICT on blood-brain-barrier (BBB) properties.

METHODS

Healthy mice were subjected to high-intensity continuous training (HICT) by treadmill running. The proteolipid protein (PLP) transfer EAE model was utilized to examine the immunomodulatory effects of training, where PLP-reactive lymph-node cells (LNCs) from HICT and sedentary donor mice were analyzed in vitro and transferred to naïve recipients that developed EAE. To examine neuroprotection, encephalitogenic LNCs from donor mice were transferred into HICT or sedentary recipient mice and the BBB was analyzed.

RESULTS

Transfer of PLP-reactive LNCs obtained from HICT donor mice attenuated EAE severity and inflammation in recipient mice. HICT markedly inhibited very late antigen (VLA)-4 and lymphocyte function-associated antigen (LFA)-1 expression in LNCs. Transfer of encephalitogenic LNCs into HICT recipients resulted in milder EAE and attenuated CNS inflammation. HICT reduced BBB permeability and the expression of intercellular adhesion molecule (ICAM)-1 and vascular cell adhesion molecule (VCAM)-1 in CNS blood vessels.

INTERPRETATION

HICT attenuates EAE development by both immunomodulatory and neuroprotective effects. The reduction in destructive CNS inflammation in EAE is attributed to systemic inhibition of autoreactive cell migratory potential, as well as reduction in BBB permeability, which are associated with reduced VLA-4/VCAM-1 and LFA-1/ICAM-1 interactions.

Laurel Attenuates Dexamethasone-Induced Skeletal Muscle Atrophy In Vitro and in a Rat Model

Prevention of muscle atrophy contributes to improved quality of life and life expectancy. In this study, we investigated the effects of laurel, selected from 34 spices and herbs, on dexamethasone (DEX)-induced skeletal muscle atrophy and deciphered the underlying mechanisms. Co-treatment of C2C12 myotubes with laurel for 12 h inhibited the DEX-induced expression of intracellular ubiquitin ligases—muscle atrophy F-box (atrogin-1/MAFbx) and muscle RING finger 1 (MuRF1)—and reduction in myotube diameter. Male Wistar rats were supplemented with 2% laurel for 17 days, with DEX-induced skeletal muscle atrophy occurring in the last 3 days. Laurel supplementation inhibited the mRNA expression of MuRF1, regulated DNA damage and development 1 (Redd1), and forkhead box class O 1 (Foxo1) in the muscles of rats. Mechanistically, we evaluated the effects of laurel on the cellular proteolysis machinery—namely, the ubiquitin/proteasome system and autophagy—and the mTOR signaling pathway, which regulates protein synthesis. These data indicated that the amelioration of DEX-induced skeletal muscle atrophy induced by laurel, is mainly mediated by the transcriptional inhibition of downstream factors of the ubiquitin-proteasome system. Thus, laurel may be a potential food ingredient that prevents muscle atrophy.

Physical exercise therapy for autoimmune neuroinflammation: Application of knowledge from animal models to patient care

Physical exercise (PE) impacts various autoimmune diseases. Accordingly, clinical trials demonstrated the safety of PE in multiple sclerosis (MS) patients and indicated beneficial outcomes. There is also an increasing body of research on the beneficial effects of exercise on experimental autoimmune encephalomyelitis (EAE), the animal model of MS, and various mechanisms underlying these effects were suggested. However, despite the documented favorable impact of PE on our health, we still lack a thorough understanding of its effects on autoimmune neuroinflammation and specific guidelines of PE therapy for MS patients are lacking. To that end, current findings on the impact of PE on autoimmune neuroinflammation, both in human MS and animal models are reviewed. The concept of personalized PE therapy for autoimmune neuroinflammation is discussed, and future research for providing biological rationale for clinical trials to pave the road for precise PE therapy in MS patients is described.

Carnosine and skeletal muscle dysfunction in a rodent multiple sclerosis model

Muscle weakness and fatigue are primary manifestations of multiple sclerosis (MS), a chronic disease of the central nervous system. Interventions that enhance muscle function may improve overall physical well-being of MS patients. Recently, we described that levels of carnosine, an endogenous muscle dipeptide involved in contractile function and fatigue-resistance, are reduced in muscle tissue from MS patients and a monophasic rodent MS model (experimental autoimmune encephalomyelitis, EAE). In the present study, we aimed to (1) confirm this finding in a chronic EAE model, along with the characterization of structural and functional muscle alterations, and (2) investigate the effect of carnosine supplementation to increase/restore muscle carnosine levels and improve muscle function in EAE. We performed muscle immunohistochemistry and ex vivo contractility measurements to examine muscle structure and function at different stages of EAE, and following nutritional intervention (oral carnosine: 3, 15 or 30 g/L in drinking water). Immunohistochemistry revealed progressively worsening muscle fiber atrophy and a switch towards a fast-twitch muscle phenotype during EAE. Using ex vivo muscle contractility experiments, we observed reductions in muscle strength and contraction speed, but no changes in muscle fatigability of EAE mice. However, carnosine levels were unaltered during all stages of EAE, and even though oral carnosine supplementation dose-dependently increased muscle carnosine levels up to + 94% after 56 days EAE, this did not improve muscle function of EAE mice. In conclusion, EAE mice display significant, yet time-dependent, muscular alterations, and carnosine intervention does not improve muscle function in EAE.

Transcranial Magnetic Stimulation Improves Muscle Involvement in Experimental Autoimmune Encephalomyelitis

Skeletal muscle is affected in experimental autoimmune encephalomyelitis (EAE), which is a model of multiple sclerosis that produces changes including muscle atrophy; histological features of neurogenic involvement, and increased oxidative stress. In this study, we aimed to evaluate the therapeutic effects of transcranial magnetic stimulation (TMS) on the involvement of rat skeletal muscle and to compare them with those produced by natalizumab (NTZ). EAE was induced by injecting myelin oligodendrocyte glycoprotein (MOG) into Dark Agouti rats. Both treatments, NTZ and TMS, were implemented from day 15 to day 35. Clinical severity was studied, and after sacrifice, the soleus and extensor digitorum longus muscles were extracted for subsequent histological and biochemical analysis. The treatment with TMS and NTZ had a beneficial effect on muscle involvement in the EAE model. There was a clinical improvement in functional motor deficits, atrophy was attenuated, neurogenic muscle lesions were reduced, and the level of oxidative stress biomarkers was lower in both treatment groups. Compared to NTZ, the best response was obtained with TMS for all the parameters analyzed. The myoprotective effect of TMS was higher than that of NTZ. Thus, the use of TMS may be an effective strategy to reduce muscle involvement in multiple sclerosis.

Histological aspects of skeletal muscle fibers splitting of C57BL/6NCrl mice

The objective of the current study is to present data on the splitting of skeletal muscle fibers in C57BL/6NCrl mice. Skeletal muscles (m. rectus femoris (m. quadriceps femoris)) from 500 (250 female and 250 male) C57BL/6NCrl mice in the 16th week of life were sampled during autopsy and afterwards standardly histologically processed. Results show spontaneous skeletal muscle fiber splitting which is followed by skeletal muscle fiber regeneration. One solitary skeletal muscle fiber is split, or is in contact with few localized splitting skeletal muscle fibers. Part of the split skeletal muscular fiber is phagocytosed, but the remaining skeletal muscular fiber splits are merged into one regenerating skeletal muscle fiber. Nuclei move from the periphery to the regenerating skeletal muscle fiber center during this process. No differences were observed between female and male mice and the morphometry results document < 1 % skeletal muscle fiber splitting. If skeletal muscular fibers splitting occurs 5 % > of all skeletal muscular fibers, it is suggested to describe and calculate this in the final histopathological report.

Immunomodulatory Effects of Exercise in Experimental Multiple Sclerosis

Multiple Sclerosis (MS) is a demyelinating and neurodegenerative disease. Though a specific antigen has not been identified, it is widely accepted that MS is an autoimmune disorder characterized by myelin-directed immune attack. Pharmacological treatments for MS are based on immunomodulatory or immunosuppressant drugs, designed to attenuate or dampen the immune reaction, to improve neurological functions. Recently, rehabilitation has gained increasing attention in the scientific community dealing with MS. Engagement of people with MS in exercise programs has been associated with a number of functional improvements in mobility, balance, and motor coordination. Moreover, several studies indicate the effectiveness of exercise against fatigue and mood disorders that are frequently associated with the disease. However, whether exercise acts like an immunomodulatory therapy is still an unresolved question. A good tool to address this issue is provided by the study of the immunomodulatory effects of exercise in an animal model of MS, including the experimental autoimmune encephalomyelitis (EAE), the Theiler's virus induced-demyelinating disease (TMEV-IDD) and toxic-demyelinating models, cuprizone (CPZ), and lysolecithin (LPC). So far, despite the availability of different animal models, most of the pre-clinical data have been gained in EAE and to a lesser extent in CPZ and LPC. These studies have highlighted beneficial effects of exercise, suggesting the modulation of both the innate and the adaptive immune response in the peripheral blood as well as in the brain. In the present paper, starting from the biological differences among MS animal models in terms of immune system involvement, we revise the literature regarding the effects of exercise in EAE, CPZ, and LPC, and critically highlight the advantages of either model, including the so-far unexplored TMEV-IDD, to address the immune effects of exercise in MS.

Exercise intensity-dependent immunomodulatory effects on encephalomyelitis

Background

Exercise training (ET) has beneficial effects on multiple sclerosis and its animal model experimental autoimmune encephalomyelitis (EAE). However, the intensity‐dependent effects of ET on the systemic immune system in EAE remain undefined.

Objective

(1) To compare the systemic immune modulatory effects of moderate versus high‐intensity ET protocols in protecting against development of EAE; (2) To investigate whether ET affects autoimmunity selectively, or causes general immunosuppression.

Methods

Healthy mice performed moderate or high‐intensity treadmill running programs. Proteolipid protein (PLP)‐induced transfer EAE was utilized to examine ET effects specifically on the systemic immune system. Lymph node (LN)‐T cells from trained versus sedentary donor mice were transferred to naïve recipients and EAE severity was assessed, by clinical assessment and histopathological analysis. LN‐T cells derived from donor trained versus sedentary PLP‐immunized mice were analyzed in vitro for proliferation assays by flow cytometry analysis and cytokine and chemokine receptor gene expression using real‐time PCR. T cell‐dependent immune responses of trained versus sedentary mice to the nonautoantigen ovalbumin and susceptibility to Escherichia coli‐induced acute peritonitis were examined.

Results

High‐intensity training in healthy donor mice induced significantly greater inhibition than moderate‐intensity training on proliferation and generation of encephalitogenic T cells in response to PLP‐immunization, and on EAE severity upon their transfer into recipient mice. High‐intensity training also inhibited LN‐T cell proliferation in response to ovalbumin immunization. E. coli bacterial counts and dissemination were not affected by training.

Interpretation

High‐intensity training induces superior effects in preventing autoimmunity in EAE, but does not alter immune responses to E. coli infection.

Regular Exercise Modifies Histopathological Outcomes of Pharmacological Treatment in Experimental Autoimmune Encephalomyelitis

Background: Although it has been suggested that healthier lifestyle may optimize effects of the immunomodulation drugs for treating multiple sclerosis (MS), the knowledge regarding this kind of interactions is limited.

Objective: The aim of the present study was to investigate the effects of treadmill exercise in combination with pharmacological treatment in an animal model for MS.

Methods: C57BL/6J female mice were subjected to daily treadmill exercise for 4 weeks before immunization and 6 weeks before clinical presentation of disease. Dimethyl fumarate (DMF) or glatiramer acetate (GA) were administered after the first clinical relapse. Histopathological analyses were carried out in the lumbar spinal cord at peak disease and at 1 or 14 days post-treatment (dpt).

Results: Exercised-GA treated animals demonstrated decreased astrocytic response in the spinal dorsal horn with an improvement in the paw print pressure. Exercised-DMF treated animals showed an increased microglial/macrophage response on both ventral and dorsal horn that were associated with clinical improvement and synaptic motoneuron inputs density.

Conclusion: The present data suggest that prior regular exercise can modify the effects of pharmacological treatment administered after the first relapse in a murine model for MS.

Muscle carnosine in experimental autoimmune encephalomyelitis and multiple sclerosis

BACKGROUND

Muscle carnosine is related to contractile function (Ca⁺⁺ handling) and buffering of exercise-induced acidosis. As these muscular functions are altered in Multiple Sclerosis (MS) it is relevant to understand muscle carnosine levels in MS.

METHODS

Tibialis anterior muscle carnosine was measured in an animal MS model (EAE, experimental autoimmune encephalomyelitis, n = 40) and controls (CON, n = 40) before and after exercise training (EAE_EX, CON_EX, 10d, 1 h/d, 24 m/min treadmill running) or sedentary conditions (EAE_SED, CON_SED). Human m. vastus lateralis carnosine of healthy controls (HC, n = 22) and MS patients (n = 24) was measured.

RESULTS

EAE muscle carnosine levels were decreased (p < .0001) by ~ 40% to ~ 64% at 10d and 17d following EAE induction (respectively) regardless of exercise (p = .823). Similarly, human MS muscle carnosine levels were decreased (- 25%, p = .03).

CONCLUSION

Muscle carnosine concentrations in an animal MS model and MS patients are substantially reduced. In EAE exercise therapy does not restore this.

Twelve Weeks of Medium-Intensity Exercise Therapy Affects the Lipoprotein Profile of Multiple Sclerosis Patients

Multiple sclerosis (MS) is an inflammatory auto-immune disease of the central nervous system (CNS). Serum glucose alterations and impaired glucose tolerance (IGT) are reported in MS patients, and are commonly associated with the development of cardio-metabolic co-morbidities. We previously found that a subgroup of MS patients shows alterations in their lipoprotein profile that are similar to a pre-cardiovascular risk profile. In addition, we showed that a high-intensity exercise training has a positive effect on IGT in MS patients. In this study, we hypothesize that exercise training positively influences the lipoprotein profile of MS patients. To this end, we performed a pilot study and determined the lipoprotein profile before (controls, n = 40; MS patients, n = 41) and after (n = 41 MS only) 12 weeks of medium-intensity continuous training (MIT, n = 21, ~60% of VO_2max) or high-intensity interval training (HIT, n = 20, ~100-200% of VO_2max) using nuclear magnetic resonance spectroscopy (NMR). Twelve weeks of MIT reduced intermediate-density lipoprotein particle count ((nmol/L); -43.4%; p < 0.01), low-density lipoprotein cholesterol (LDL-c (mg/dL); -7.6%; p < 0.05) and VLDL size ((nm); -6.6%; p < 0.05), whereas HIT did not influence the lipoprotein profile. These results show that MIT partially normalizes lipoprotein alterations in MS patients. Future studies including larger patient and control groups should determine whether MIT can reverse other lipoprotein levels and function and if these alterations are related to MS disease progression and the development of co-morbidities.

The Effects of Aerobic Exercise on the Recovery of Walking Ability and Neuroplasticity in People with Multiple Sclerosis: A Systematic Review of Animal and Clinical Studies

INTRODUCTION

Walking is of high priority for people with multiple sclerosis (PwMS). It remains unclear whether aerobic exercise can improve walking ability and upregulate neurotrophins. This review aims to consolidate evidence to develop optimal aerobic training parameters to enhance walking outcomes and neuroplasticity in PwMS.

METHODS

Clinical studies examining aerobic exercise for ≥3 weeks, having outcomes on walking with or without neurotrophic markers, were included. Studies utilizing animal models of MS were included if they employed aerobic exercise with outcomes on neurological recovery and neurotrophins. From a total of 1783 articles, 12 clinical and 5 animal studies were included.

RESULTS

Eleven clinical studies reported improvements in walking ability. Only two clinical studies evaluated both walking and neurotrophins, and neither found an increase in neurotrophins despite improvements in walking. Patients with significant walking impairments were underrepresented. Long-term follow-up revealed mixed results. Two animal studies reported a positive change in both neurological recovery and neurotrophins.

CONCLUSION

Aerobic exercise improves walking ability in PwMS. Gains are not consistently maintained at 2- to 9-month follow-up. Studies examining levels of neurotrophins are inconclusive, necessitating further research. Aerobic exercise enhances both neurological recovery and neurotrophins in animal studies when started 2 weeks before induction of MS.

Comprehensive catwalk gait analysis in a chronic model of multiple sclerosis subjected to treadmill exercise training

BACKGROUND

Multiple sclerosis (MS) is a demyelinating disease with a wide range of symptoms including walking impairment and neuropathic pain mainly represented by mechanical allodynia. Noteworthy, exercise preconditioning may affect both walking impairment and mechanical allodynia. Most of MS symptoms can be reproduced in the animal model named experimental autoimmune encephalomyelitis (EAE). Usually, neurological deficits of EAE are recorded using a clinical scale based on the development of disease severity that characterizes tail and limb paralysis. Following paralysis recovery, subtle motor alterations and even mechanical allodynia investigation are difficult to record, representing sequels of peak disease. The aim of the present study was to investigate the walking dysfunction by the catwalk system (CT) in exercised and non-exercised C57BL/6 mice submitted to EAE with MOG35-55 up to 42 days post-induction (dpi).

METHODS

Twenty-four C57BL/6 female mice were randomly assigned to unexercised (n = 12) or exercised (n = 12) groups. The MOG35-55 induced EAE model has been performed at the beginning of the fifth week of the physical exercise training protocol. In order to characterize the gait parameters, we used the CT system software version XT 10.1 (Noldus Inc., The Netherlands) from a basal time point (before induction) to 42 days post induction (dpi). Statistical analyses were performed with GraphPad Prisma 4.0 software.

RESULTS

Data show dynamic gait changes in EAE mice including differential front (FP) and hind paw (HP) contact latency. Such findings are hypothesized as related to an attempt to maintain balance and posture similar to what has been observed in patients with MS. Importantly, pre-exercised mice show differences in the mentioned gait compensation, particularly at the propulsion sub-phase of HP stand. Besides, we observed reduced intensity of the paw prints as well as reduced print area in EAE subjects, suggestive of a development of chronic mechanical allodynia in spite of being previously exercised.

CONCLUSIONS

Our data suggest that Catwalk system is a useful tool to investigate subtle motor impairment and mechanical allodynia at chronic time points of the EAE model, improving the functional investigation of gait abnormalities and demyelination sequelae.

Short-Term and Long-Term Effects of an Exercise-Based Patient Education Programme in People with Multiple Sclerosis: A Pilot Study

Background. Although people with Multiple Sclerosis (pwMS) benefit from physical exercise, they still show reduced physical activity and exercise behaviour. This study aimed to investigate short- and long-term effects of an exercise-based patient education programme (ePEP) that focuses on empowering pwMS to a sustainable and self-regulated exercise training management. Methods. Fourteen pwMS were randomly assigned to immediate experimental group (EG-I: n = 8) and waitlist-control group (EG-W: n = 6) and attended biweekly in a six-week ePEP. All participants were measured for walking ability, quality of life, fatigue, and self-efficacy towards physical exercise before and after the ePEP, after 12 weeks, and one year after baseline. Short-term effects were analysed in a randomised control trial and long-term effects of all ePEP participants (EG-I + EG-W = EG-all) in a quasi-experimental design. Results. Only functional gait significantly improved in EG-I compared to EG-W (p = 0.008, r = −0.67). Moderate to large effects were found in EG-all for walking ability. Not significant, however, relevant changes were detected for quality of life and fatigue. Self-efficacy showed no changes. Conclusion. The ePEP seems to be a feasible option to empower pwMS to a self-regulated and sustainable exercise training management shown in long-term walking improvements.

Forced exercise increases muscle mass in EAE despite early onset of disability

We aimed to determine whether 10 days of treadmill exercise can increase skeletal muscle mass and intramuscular concentrations of brain derived neurotrophic factor (BDNF) and nerve growth factor (NGF) in experimental autoimmune encephalomyelitis (EAE). Forty female Lewis rats were randomly assigned to either EAE sedentary (EAE-Sed), EAE exercise (EAE-Ex), Control sedentary (Con-Sed) and Control exercise (Con-Ex). Exercising animals completed a 10 day forced exercising training program. Hind limb skeletal muscles were excised and weighed with soleus muscle used for BDNF and NGF quantification. Statistical analysis was done using a one-way analysis of variance. Disability was more pronounced in the EAE-Ex group than in the EAE-Sed group. Exercising animals (EAE-Ex and Con-Ex) had significantly greater bilateral EDL, plantaris and gastrocnemius muscle mass compared to their sedentary animals (p=0.01). The EAE-Ex group had significantly higher NGF concentrations (1.98+/-0.3 pg/mg) compared to Con-Ex (0.96+/-0.07 pg/mg, p=0.003) and Con-Sed (1.2+/-0.2 pg/mg, p=0.04) groups. The main effect of exercise represented a significantly lower BDNF concentrations in the soleus of exercising animals compared to sedentary animals (p=0.03). Our study provides preliminary evidence that exercise increases skeletal muscle mass despite the early onset of disability in EAE animals.