Forelimb Grip Strength Research Articles

All-Trans Retinoic Acid Exerts Neuroprotective Effects in Amyotrophic Lateral Sclerosis-Like Tg (SOD1*G93A)1Gur Mice.

All-trans retinoic acid (ATRA), a ligand of retinoic acid receptors, could regulate various biological processes by activating retinoic acid signals. Recent studies suggested that ATRA displays multiple neuroprotective effects and thereby alleviates the disease progression in a variety of neurological diseases. Our previous studies found that the impaired retinoic acid signal decreased ALDH1A2, an essential synthetase of ATRA, in the spinal cord of ALS mice. Here, we evaluated the neuroprotective and neurorestorative effects of ATRA in a SOD1-G93A transgenic mice model of ALS. We administrated ATRA(3mg/kg) daily from the onset stage to the progression stage for 5weeks. Behavioral tests showed that ATRA improved the forelimb grip strength in ALS mice and may slow the disease progression, but not the body weight. ATRA could completely reverse the impaired retinoic acid receptor alpha (RARα) signal in the spinal cord of ALS mice. This effect was accompanied by enhancing the degradation of misfolded proteins via the ubiquitin-proteasome system, regulating the oxidative stress, inhibiting the astrocyte activation, and promoting the neurotrophic signal recovery. Our findings are the first to indicate that the damaged retinoic acid signal is involved in the pathogenesis of ALS, and ATRA could induce the functional neuroprotection via repairing the damaged retinoic acid signal.

A Ketogenic Diet Mitigates Pancreatic Cancer-Associated Cachexia in Mice

Abstract Objectives Cancer cachexia is a multifactorial disorder characterized by involuntary and ongoing wasting of skeletal muscle. More than 80% of patients with pancreatic ductal adenocarcinoma (PDA) suffer from cachexia and up to 20% die directly from it. The ketogenic diet (KD) has been shown to improve health span in old mice. However, its effect in cancer remains elusive. Therefore, our objective was to determine whether a KD mitigates cachexia and/or increases survival in a clinically relevant genetically-engineered LSL-KrasG12D/+; LSL-Trp53R172H/+; Pdx1-Cre (KPC) model of PDA. Methods After confirming the presence of a pancreatic tumor by high resolution ultrasound imaging, male and female KPC mice were fed either a control diet (CD; %kcal: 14% protein, 70% carb, 16% fat), or a KD (%kcal: 14% protein, < 1% carb, 85% fat) until an endpoint related to PDA was met. Forelimb grip strength, body composition, and non-fasting glucose and ketone levels were evaluated at baseline, monthly and at time of euthanasia. Results After 1 month on the experimental diets, ketone levels were significantly higher in mice fed a KD compared to those fed a CD (p < 0.0001). After two months, KPC mice fed a KD significantly outperformed the KPC mice fed CD in the grip strength test, which assesses skeletal muscle function (p = 0.032). Moreover, the weight of the gastrocnemius muscle was significantly higher in KPC mice fed a KD compared to mice fed a CD (p = 0.024). However, the KD had no significant effect extending KPC survival (p = 0.527), or on the tumor/pancreas weight (p = 0.998). Conclusions A KD maximizes and preserves motor function strength during PDA progression. Additional studies are warranted to evaluate the mechanisms of how KD improves and preserves muscle strength in PDA. Funding Sources Startup funds and a University of California Comprehensive Cancer Center award to GGM. NEC is supported with a fellowship from UC-MEXUS.

The Long‐Term Effects of Exercise Mitigate Deleterious Healthspan Changes and Cancer Incidence in Mice Following Diet‐Induced Obesity and Radiation Exposure

There are nearly 16 million cancer survivors living in the United States today, with two‐thirds of them having received radiation therapy as part of their treatment. Furthermore, there is a concurrent increase in obesity and physical inactivity among this population. Combined with the effects of ionizing radiation (IR), these host factors are increasing the risk of secondary, treatment‐induced cancers and may contribute to poor healthspan outcomes in cancer survivors. As such, a critical need exists to develop a better understanding of how these host factors interact with radiation exposure, such that we can provide cancer survivors with better lifestyle recommendations to enhance their overall quality of life and decrease their secondary cancer risk. Male CBA mice were randomly divided into a control diet group (CTRL) or a 45% high fat diet group (HFD) to induce obesity. At nine weeks of age, half of the mice in each dietary group began a treadmill exercise training intervention (EX), or remained sedentary (SED), and were then all exposed to ionizing radiation (3 Gy) at 13 weeks of age. Healthspan was measured in each group at 17 months of age by assessing: endurance performance, metabolic and locomotor activity, depression‐like behaviour, forelimb grip strength and plasma clinical chemistry. Endurance performance was significantly greater in CTRL/EX compared to both HFD groups 5 days pre‐IR and compared to both SED groups 5 months post‐IR (both p<0.05). Metabolic analysis revealed a significant increase in the respiratory exchange ratio in CTRL compared to HFD mice (p<0.05), but there were no significant differences in O2 consumption, CO2, or heat production (p>0.05). There was also a trend for an increase in locomotor activity in the CTRL/EX compared to CTRL/SED group during their light and dark cycle (p = 0.06 and p = 0.108, respectively). Further, there was a significant decrease in depression‐like behaviour among HFD compared to CTRL mice, and EX compared to SED mice (p<0.05), as well as a significant decrease in forelimb grip strength normalized to body weight among HFD compared to CTRL mice (p<0.05). Additionally, there was a significant increase in total cholesterol levels among HFD compared to CTRL mice (p<0.05). Interestingly, the CTRL/EX and HFD/EX groups had a 20% decrease in cancer incidence compared to the HFD/SED group, and EX mice had a 17.5% decrease in cancer incidence compared to SED mice, independent of diet (both p>0.05). Our current findings suggest that long‐term exercise and dietary interventions should be implemented in cancer survivors exposed to radiation therapy in order to improve healthspan and potentially protect against secondary cancer incidence.Support or Funding InformationThe American Institute of Cancer Research (AICR), The Natural Sciences and Engineering Research Council of Canada (NSERC), and The Canadian Institutes of Health Research (CIHR)

Connexin-43 reduction prevents muscle defects in a mouse model of manifesting Duchenne muscular dystrophy female carriers

Duchenne muscular dystrophy (DMD) is a severe X-linked neuromuscular disorder that affects males. However, 8% of female carriers are symptomatic and underrepresented in research due to the lack of animal models. We generated a symptomatic mouse model of DMD carriers via injection of mdx (murine DMD) embryonic stem cells (ESCs) into wild-type (WT) blastocysts (mdx/WT chimera). mdx/WT chimeras developed cardiomyopathic features and dystrophic skeletal muscle phenotypes including elevated mononuclear invasion, central nucleation, fibrosis and declined forelimb grip strength. The disease was accompanied by connexin-43 (Cx43) aberrantly enhanced in both cardiac and skeletal muscles and remodeled in the heart. Genetic reduction of Cx43-copy number in mdx/WT-Cx43(+/−) chimeras protected them from both cardiac and skeletal muscle fiber damage. In dystrophic skeletal muscle, Cx43 expression was not seen in the fibers but in adjacent F4/80+ mononuclear cells. Ethidium Bromide uptake in purified F4/80+/CD11b+ mdx macrophages revealed functional activity of Cx43, which was inhibited by administration of Gap19 peptide mimetic, a Cx43 hemichannel-specific inhibitor. Thus, we suggest that Cx43 reduction in symptomatic DMD carrier mice leads to prevention of Cx43 remodeling in the heart and prevention of aberrant Cx43 hemichannel activity in the skeletal muscle macrophages neighboring Cx43 non-expressing fibers.

The rat model of COPD skeletal muscle dysfunction induced by progressive cigarette smoke exposure: a pilot study

BackgroundChronic obstructive pulmonary disease (COPD) skeletal muscle dysfunction is a prevalent malady that significantly affects patients’ prognosis and quality of life. Although the study of this disease has attracted considerable attention, a definite animal model is yet to be established. This study investigates whether smoke exposure could lead to the development of a COPD skeletal muscle dysfunction model in rats.MethodsSprague Dawley rats were randomly divided into model (MG, n = 8) and control groups (CG, n = 6). The MG was exposed to cigarette smoke for 16 weeks while the CG was not. The body weight and forelimb grip strength of rats were monitored monthly. The pulmonary function and the strength of tibialis anterior muscle were assessed in vitro and compared after establishing the model. The histological changes in lung and gastrocnemius muscles were observed. The expressions of interleukin (IL)-6, IL-8, and tumor necrosis factor (TNF)-α were detected by ELISA, while the expressions of Atrogin-1 and MuRF1 in the gastrocnemius muscle were determined by Western blotting.ResultsSmoke exposure slowly increases the body weight and forelimb grip strength of MG rats, compared to CG rats. However, it significantly decreases the pulmonary ventilation function and the skeletal muscle contractility of the MG in vitro. Histologically, the lung tissues of MG show typical pathological manifestations of emphysema, while the skeletal muscles present muscular atrophy. The expressions of IL-6, IL-8, and TNF-α in MG rats are significantly higher than those measured in CG rats. Increased levels of Atrogin-1 and MuRF1 were also detected in the gastrocnemius muscle tissue of MG.ConclusionProgressive smoking exposure decreases the contractile function of skeletal muscles, leading to muscular atrophy. It also increases the expressions of inflammatory and muscle protein degradation factors in COPD rats. This indicates that smoke exposure could be used to establish a COPD skeletal muscle dysfunction model in rats.

Expressions of matrix metalloproteinase-1 and tissue inhibitor of metalloproteinases 1 in skeletal muscles of aged rats with sarcopenia

To investigate the changes of skeletal muscle mass and strength and the expressions of matrix metalloproteinase-1 (MMP-1), tissue inhibitor of metalloproteinases-1 (TIMP-1) and collagen-1 in the skeletal muscle of aged rats with sarcopenia. With 11 young (6-month-old) SD rats as control group, 18 aged (25-month-old) SD rats were divided into two groups (n=9) according to the relative lean mass determined dual X-ray absorptiometry (DXA), namely aged control group and aged sarcopenia group (the relative lean mass was 2SD higher in aged control than in aged sarcopenia group. The forelimb grip strength of the rats was measured using an electronic grip strength meter. The extracellular matrix (ECM) of the rat's gastrocnemius was observed with HE staining and sirius Red staining, and the protein expressions of collagen-1, MMP-1, and TIMP-1 in the muscular tissues were detected with Western blotting. Compared with the young rats, the aged control rats had significantly lower relative grip strength (P < 0.01) and increased expressions of collagen-1 and TIMP-1 (P < 0.05) and ECM content in the skeletal muscles, but the relative lean mass and MMP-1 protein expression were comparable between the two groups (P>0.05). Compared with the aged control rats, the aged sarcopenic rats had significantly lowered relative lean mass (P < 0.01) and MMP-1 expressions of (P < 0.05) and increased expressions of collagen-1 and TIMP-1 proteins and ECM content in the muscular tissues (P < 0.05) without significant changes in the relative grip strength (P>0.05). MMP-1/TIMP-1 imbalance in the skeletal muscle during aging affects ECM metabolism and leads to increased collagen fibers, which in turn affects the skeletal muscle mass and function and contribute to the onset of sarcopenia.

Supplementation of L-Arginine, L-Glutamine, Vitamin C, Vitamin E, Folic Acid, and Green Tea Extract Enhances Serum Nitric Oxide Content and Antifatigue Activity in Mice.

It has been reported that abundant nitric oxide content in endothelial cells can increase exercise performance. The purpose of this study was to evaluate the potential beneficial effects of a combined extract comprising L-arginine, L-glutamine, vitamin C, vitamin E, folic acid, and green tea extract (LVFG) on nitric oxide content to decrease exercise fatigue. Male ICR (Institute of Cancer Research) mice were randomly divided into 4 groups and orally administered LVFG for 4 weeks. The 4-week LVFG supplementation significantly increased serum nitric oxide content in the LVFG-1X and LVFG-2X groups. Antifatigue activity and exercise performance were evaluated using forelimb grip strength, exhaustive swimming test, and levels of serum lactate, ammonia, glucose, and creatine kinase (CK) after an acute swimming exercise. LVFG supplementation dose-dependently improved exercise performance and nitric oxide content, and it dose-dependently decreased serum ammonia and CK activity after exhaustive swimming test. LVFG's antifatigue properties appear to manifest by preserving energy storage (as blood glucose) and increasing nitric oxide content. Taken together, our results show that LVFG could have the potential for alleviating physical fatigue due to its pharmacological effect of increasing serum nitric oxide content.

Chinese herbal decoction (Danggui Buxue Tang) supplementation augments physical performance and facilitates physiological adaptations in swimming rats

Context Danggui Buxue Tang (DBT), one of the popular Danggui (DG) decoctions, has traditionally been used to nourish ‘qi’ (vital energy) and enrich ‘blood’ (body circulation). DBT may possess performance-enhancing effects. Objective This work determines whether DBT can improve physical capacity and alter energy expenditure under exercise training. Materials and methods Forty male Wistar rats were assigned to four groups: sedentary (SE), exercise training (ET), ET supplemented with 0.3 g/kg rat/d DG extract, and ET supplemented with 1.8 g/kg rat/d DBT extract. The supplementations were administered via oral gavage. During the 21-day treatment period, the exercised groups were subjected to a protocol of swimming training with a gradually increased load. Physical performance evaluation was assessed using the forelimb grip strength test and an exhaustive swimming test. Muscle glycogen contents and exercise-related biochemical parameters were analysed. Results Both herbal supplementations remarkably increased the grip strength (DG by 49.7% and DBT by 85.7%) and prolonged the swimming time (DG by 48.4% and DBT by 72.7%) compared with SE. DBT spared a certain amount of glycogen in the muscle cells under exercise training. Regarding the regulation of fuel usage, DBT had a positive impact alongside ET on promoting aerobic glycolysis via significantly decreasing serum lactate by 31.6% and lactic dehydrogenase levels by 61.8%. Conclusions This study found that DBT could be considered a promising sports ergogenic aid for athletic population or fitness enthusiasts. Future work focussing on isolating the bioactive components that truly provide the ergogenic effects would be of interest.

Micro-dystrophin Gene Therapy Partially Enhances Exercise Capacity in Older Adult mdx Mice

Micro-dystrophin (μDys) gene therapeutics can improve striated muscle structure and function in different animal models of Duchenne muscular dystrophy. Most studies, however, used young mdx mice that lack a pronounced dystrophic phenotype, short treatment periods, and limited muscle function tests. We, therefore, determined the relative efficacy of two previously described μDys gene therapeutics (rAAV6:μDysH3 and rAAV6:μDys5) in 6-month-old mdx mice using a 6-month treatment regimen and forced exercise. Forelimb and hindlimb grip strength, metabolic rate (VO2 max), running efficiency (energy expenditure), and serum creatine kinase levels similarly improved in mdx mice treated with either vector. Both vectors produced nearly identical dose-responses in all assays. They also partially prevented the degenerative effects of repeated high-intensity exercise on muscle histology, although none of the metrics examined was restored to normal wild-type levels. Moreover, neither vector had any consistent effect on respiration while exercising. These data together suggest that, although μDys gene therapy can improve isolated and systemic muscle function, it may be only partially effective when dystrophinopathies are advanced or when muscle structure is significantly challenged, as with high-intensity exercise. This further suggests that restoring muscle function to near-normal levels will likely require ancillary or combinatorial treatments capable of enhancing muscle strength.

Effects of Aerobic Exercise during Pregnancy on Neurobehavioral Performances and Serum Levels of GDNF in Adult Male Mice Offspring

Clinical evidence indicates that physical activity during pregnancy may modulate the brain development and improve the neurobehavioral functions of the offspring. Nevertheless, the mechanisms by which exercise during pregnancy may cause such changes are not fully understood. Our study, therefore, aimed to investigate the effects of aerobic exercise (AX) during pregnancy on neurobehavioral functions of adult male mice offspring with emphasis on serum levels of glial cell line-derived neurotrophic factor (GDNF). After pregnancy stabilization, pregnant mice were divided into exercise and control groups. The exercise group performed moderate-intensity AX on a treadmill during pregnancy. The cognitive function, motor coordination, forelimb grip strength, and pain tolerability of adult male offspring were evaluated using the novel object recognition task (NORT), Morris water maze (MWM), raised-beam task, grip strength, and hot-plate test (HPT). The serum levels of GDNF were also measured using the ELISA technique. Results showed that maternal moderate forced exercise improved the cognitive function and motor coordination and also increased pain tolerability in the offspring. It was also observed that AX during pregnancy elevated the GDNF serum level in the offspring. However, AX during pregnancy exerted no significant effects on the body mass and number of offspring, as well as on the forelimb grip strength. Our findings showed that moderate-intensity AX could improve the neurobehavioral functions in adult offspring due, in particular, to increased serum levels of GDNF.

Focal and dose-dependent neuroprotection in ALS mice following AAV2-neurturin delivery

Neurotrophic factors as candidates for ALS therapeutics have previously been studied in the context of attempts to slow disease progression. For a variety of reasons, clinical trials of neurotrophic factors have failed to show efficacy in ALS patients. Previous studies in Parkinson's Disease (PD) models have shown promise with the use of recombinant adeno-associated virus serotype-2 (rAAV2)-neurturin (NRTN) [AAV2-NRTN] providing neuroprotection and behavioral improvements in preclinical models which subsequently resulted in several clinical studies in patients with PD. Given that this neurotrophic compound has not been studied in the context of ALS, we conducted a study of AAV2-NRTN to assess the preclinical safety, tolerability, biodistribution, and efficacy of this compound in an ALS mouse model. SOD1G93A mice were injected with AAV2-NRTN intraspinally at several doses into the cervical spinal cord at 60 days of age. NRTN expression was noted in motor neurons (MNs) of the targeted cervical spinal cord as well as in their neuromuscular junction projections but not in the lumbar spinal cord, which was not targeted. Neuropathologically, a dose-dependent neuroprotective effect was seen in cervical MNs and neuromuscular junctions that was reflected in a slowing of forelimb grip strength decline. As expected, this neuroprotection was found to be focal and was not seen beyond the immediate region of injection. Overall, there were no increases in morbidity, changes in serum chemistries or blood counts and no cases of drug-related mortality. Because there is a broad clinical experience for this compound, these data provide evidence to support further investigation of AAV2-NRTN as a potential ALS therapeutic.

Ubiquinol Supplementation Alters Exercise Induced Fatigue by Increasing Lipid Utilization in Mice.

Ubiquinol (QH), a reduced form of coenzyme Q10, is a lipid antioxidant that is hydro-soluble and is commonly formulated in commercial supplements. Ubiquinol has been increasingly reported to exert antioxidant functions, in addition to its role in the cell energy-producing system of mitochondria and adenosine triphosphate (ATP) production. The aim of this study was to assess the potential beneficial effects of QH on anti-fatigue and ergogenic functions following physiological challenge. Forty 8-week-old male Institute of Cancer Research (ICR) mice were divided into four groups (n = 10 for each group): Group 1 (vehicle control or oil only); Group 2 (1X QH dose or 102.5 mg/kg); Group 3 (2X QH dose or 205 mg/kg); Group 4 (6X QH dose or 615 mg/kg). Anti-fatigue activity and exercise performance were studied using the forelimb grip strength experiment and exhaustive weight-loaded swimming time, and levels of serum lactate, ammonia, glucose, BUN (blood urea nitrogen), creatine kinase (CK), and free fatty acids (FFA) after an acute exercise challenge. The forelimb grip strength and exhaustive weight-loaded swimming time of the QH-6X group were significantly higher than those of the other groups. QH supplementation dose-dependently reduced serum lactate, ammonia, and CK levels and increased the FFA concentration after acute exercise. In addition, QH increased the liver and muscle glycogen content, an important energy source during exercise. Therefore, the results suggest that QH formulation is a safe dietary supplement for amelioration of fatigue and for promoting exercise performance.

Physiological and Biochemical Effects of Intrinsically High and Low Exercise Capacities Through Multiomics Approaches.

Regular exercise prevents lipid abnormalities and conditions such as diabetes mellitus, hypertension, and obesity; it considerably benefits sedentary individuals. However, individuals exhibit highly variable responses to exercise, probably due to genetic variations. Animal models are typically used to investigate the relationship of intrinsic exercise capacity with physiological, pathological, psychological, behavioral, and metabolic disorders. In the present study, we investigated differential physiological adaptations caused by intrinsic exercise capacity and explored the regulatory molecules or mechanisms through multiomics approaches. Outbred ICR mice (n = 100) performed an exhaustive swimming test and were ranked based on the exhaustive swimming time to distinguish intrinsically high- and low-capacity groups. Exercise performance, exercise fatigue indexes, glucose tolerance, and body compositions were assessed during the experimental processes. Furthermore, the gut microbiota, transcriptome, and proteome of soleus muscle with intrinsically high exercise capacity (HEC) and low exercise capacity (LEC) were further analyzed to reveal the most influential factors associated with differential exercise capacities. HEC mice outperformed LEC mice in physical activities (exhaustive swimming and forelimb grip strength tests) and exhibited higher glucose tolerance than LEC mice. Exercise-induced peripheral fatigue and the level of injury biomarkers (lactate, ammonia, creatine kinase, and aspartate aminotransferase) were also significantly lower in HEC mice than in LEC mice. Furthermore, the gut of the HEC mice contained significantly more Butyricicoccus than that of the LEC mice. In addition, transcriptome data of the soleus muscle revealed that the expression of microRNAs that are strongly associated with exercise performance-related physiological and metabolic functions (i.e., miR-383, miR-107, miR-30b, miR-669m, miR-191, miR-218, and miR-224) was higher in HEC mice than in LEC mice. The functional proteome data of soleus muscle indicated that the levels of key proteins related to muscle function and carbohydrate metabolism were also significantly higher in HEC mice than in LEC mice. Our study demonstrated that the mice with various intrinsic exercise capacities have different gut microbiome as well as transcriptome and proteome of soleus muscle by using multiomics approaches. The specific bacteria and regulatory factors, including miRNA and functional proteins, may be highly correlated with the adaptation of physiological functions and exercise capacity.

The hot water extract and active components nicotinamide and guanosine of the leather carp Cyprinus carpio nudis improve exercise performance in mice.

We identified the main active, exercise performance-enhancing compounds in a hot water extract of the leather carp, Cyprinus carpio nudus, as nicotinamide and guanosine. Mice were fed casein (30mg/ml) enriched with nicotinamide (0.1mg/ml) and guanosine (0.05mg/ml) once daily for a week at 10µl/g body weight. Swimming endurance (57%) and forelimb grip strength (21%) were increased significantly. The diet had little effect on body weight. After the swimming exercise, the blood glucose and superoxide dismutase levels were significantly higher (137% and 131%, respectively) than in the saline controls. The blood lactate level was 90% of that in the controls. The estimated amount of nicotinamide in the carp fillet was 26.2mg/kg. These results suggest that the triple combination of casein with nicotinamide and guanosine improves exercise performance and delays the onset of fatigue, supporting the traditional use of carp extract in healthcare as a tonic soup. PRACTICAL APPLICATIONS: The triple-combination of casein (30mg/ml) + nicotinamide (0.1mg/ml) + guanosine (0.05mg/ml) significantly enhanced the exercise performance and anti-fatigue in mice, supporting the traditional use of carp extract in healthcare as a tonic soup.

Antifatigue Activity and Exercise Performance of Phenolic-Rich Extracts from Calendula officinalis, Ribes nigrum, and Vaccinium myrtillus.

Calendula officinalis, Ribes nigrum, and Vaccinium myrtillus (CRV) possess a high phenolic compound content with excellent antioxidant activity. Dietary antioxidants can reduce exercise-induced oxidative stress. Consumption of large amounts of phenolic compounds is positively correlated with reduction in exercise-induced muscle damage. Research for natural products to improve exercise capacity, relieve fatigue, and accelerate fatigue alleviation is ongoing. Here, CRV containing a large total phenolic content (13.4 mg/g of CRV) demonstrated antioxidant activity. Ultra-performance liquid chromatography quantification revealed 1.95 ± 0.02 mg of salidroside in 1 g of CRV. In the current study, CRV were administered to mice for five weeks, and the antifatigue effect of CRV was evaluated using the forelimb grip strength test; weight-loaded swimming test; and measurement of fatigue-related biochemical indicators, such as blood lactate, ammonia, glucose, blood urea nitrogen (BUN), and creatine kinase (CK) activity; and muscle and liver glycogen content. The results indicated that in CRV-treated mice, the forelimb grip strength significantly increased; weight-loaded swimming time prolonged; their lactate, ammonia, BUN, and CK activity decreased, and muscle and liver glucose and glycogen content increased compared with the vehicle group. Thus, CRV have antifatigue activity and can increase exercise tolerance.

The ethanol extract from the rhodophyta Gloiopeltis furcata and its active ingredient docosahexaenoic acid improve exercise performance in mice

The effectiveness of natural bioresources at enhancing exercise performance is of interest to those in sports and health care. The use of 29 common seaweed species as supplements to enhance exercise performance and the recovery from physical fatigue was evaluated. The ethanol extract of the red seaweed Gloiopeltis furcata (GFE) had the greatest effect on forelimb grip strength and swimming endurance in mice. The optimal daily dose of GFE was 0.1mg per 10μl per g of body weight. GFE significantly increased muscle mass but had little effect on body weight and fatty deposits. The extract also significantly raised the blood superoxide dismutase and high-density lipoprotein cholesterol levels, while reducing the lactate and urea levels (p<0.05). Docosahexaenoic acid (DHA) from GFE made the greatest contribution to improving physical exercise performance. These results support the use of GFE and DHA in health food products for enhancing physical performance. PRACTICAL APPLICATIONS: The study shows the exercise enhancement and anti-fatigue activities of GFE using the forelimb grip strength test, forced swimming endurance test, muscle mass measurement, and blood biochemical parameters. These results support the use of GFE and its active constituent DHA in functional foods or nutraceuticals for enhancing physical performance.

Muscular and mitochondrial effects of long-term fluoxetine treatment in mice, combined with physical endurance exercise on treadmill

AimFluoxetine, one of the first newer SSRI antidepressant, is an extremely popular treatment for depression that could improve mental health problems. Many recent studies have suggested that SSRI have potential beneficial effects on skeletal muscle tissue. Main methodWe evaluated the potential beneficial effects of oral fluoxetine (18 mg/kg/day for 6 weeks) on muscle performance, after 6 weeks of physical exercise on treadmill. Male mice were randomly assigned to four groups (n = 12 per group) for treatment. Each group received treatment with following specifications: 1) no exercise with vehicle treatment (SED-S); 2) no exercise with fluoxetine treatment (SED-F); 3) exercise with vehicle treatment (EX-S); and 4) exercise with fluoxetine treatment (EX-F). Exercise performances were assessed based on the exhaustive running time and forelimb grip strength, anxious behavior by elevated plus-maze and open-field tests. Mitochondrial enzymes activity and ROS production were measured in the gastrocnemius and soleus muscles. Key findingFluoxetine treatment had a significant effect on maximal aerobic capacity in mice without exercise, but more significant effects on gripping strength and anxiety when combined with exercise training, e.g. increased strength and decreased anxiety. SignificanceFluoxetine treatment and exercise stimulation also had synergistic effects on strength and increased mitochondrial activity, cellular oxidative and antioxidant capacity in two different muscles.

Impact of Dietary Protein Source on Muscle Performance: An in-vivo Behavioral Assay (OR26-05-19)

ObjectivesTo analyze the impact of different sources of protein (pea, whey or casein) on functional muscle performance in C57BL/6 mice. MethodsA total of 21 mice were randomized to protein intervention groups. Mice were individually caged in a temperature controlled and 12-h light-dark cycle room. Subjects were randomly assigned to casein, whey, and pea protein sourced diets, matched by sex. Total energy (3.77 ± 0.04 kcal/g) and macronutrient composition (% of total energy: carbohydrate 66%, protein 18% and fat 16%) were matched across diets. Body weight and amount of food consumed was measured weekly. Functional muscle performance was measured by forelimb grip strength test using an Accuforce Cadet Force Gage and hanging test using Kondziela’s inverted screen test capped at 600 seconds (at intervention week 9). The recorded strength and hang time measurements were corrected for body-mass. Data processing and analyses were performed in IBM SPSS Statistics 25. ResultsExcluding 2 mice due to outliers, the total number of mice per group were: casein (n = 9), whey (n = 6), and pea (n = 5). No baseline differences in body weight or average amount of food consumed per week were observed between groups. However, mice on the pea protein diet gained significantly more weight (8 ± 2g) compared to whey (4 ± 2g) and casein (2 ± 2g) diet groups (P < 0.007). Mice fed with whey protein sourced diets showed significantly stronger maximum fore limb grip strength (237 ± 21g) compared to pea (200 ± 7g) and casein (219 ± 26g) fed mice (P < 0.005). Body-mass corrected average and maximum grip strength tests showed that mice consuming pea protein sourced were significantly weaker compared to the casein protein sourced diet group, but not to whey protein sourced diet group (Table 1). ConclusionsNo observable differences were found between whey and casein in functional muscle performance of C57BL/6 mice when corrected for body weight. However, the pea sourced protein diet resulted in higher weight gain and weaker functional muscle performance measurements. Funding SourcesUniversity of Massachusetts Lowell Seed Grant (NK, KM, MG). Supporting Tables, Images and/or Graphs▪

Dysferlin-deficiency has greater impact on function of slow muscles, compared with fast, in aged BLAJ mice.

Dysferlinopathies are a form of muscular dystrophy caused by gene mutations resulting in deficiency of the protein dysferlin. Symptoms manifest later in life in a muscle specific manner, although the pathomechanism is not well understood. This study compared the impact of dysferlin-deficiency on in vivo and ex vivo muscle function, and myofibre type composition in slow (soleus) and fast type (extensor digitorum longus; EDL) muscles using male dysferlin-deficient (dysf-/-) BLAJ mice aged 10 months, compared with wild type (WT) C57Bl/6J mice. There was a striking increase in muscle mass of BLAJ soleus (+25%) (p<0.001), with no strain differences in EDL mass, compared with WT. In vivo measures of forelimb grip strength and wheel running capacity showed no strain differences. Ex vivo measures showed the BLAJ soleus had faster twitch contraction (-21%) and relaxation (-20%) times, and delayed post fatigue recovery (ps<0.05); whereas the BLAJ EDL had a slower relaxation time (+11%) and higher maximum rate of force production (+25%) (ps<0.05). Similar proportions of MHC isoforms were evident in the soleus muscles of both strains (ps>0.05); however, for the BLAJ EDL, there was an increased proportion of type IIx MHC isoform (+5.5%) and decreased type IIb isoform (-5.5%) (ps<0.01). This identification of novel differences in the impact of dysferlin-deficiency on slow and fast twitch muscles emphasises the importance of evaluating myofibre type specific effects to provide crucial insight into the mechanisms responsible for loss of function in dysferlinopathies; this is critical for the development of targeted future clinical therapies.

Lithium chloride corrects weakness and myopathology in a preclinical model of LGMD1D.

ObjectiveTo understand DNAJB6's function in skeletal muscle and identify therapeutic targets for limb-girdle muscular dystrophy 1D (LGMD1D).MethodsDNAJB6 knockout (KO) myoblasts were generated with Crispr/cas9 technology, and differentially accumulated proteins were identified using stable isotope labeling, followed by quantitative mass spectrometry. Cultured KO myotubes and mouse muscle from DNAJB6b-WT or DNAJB6b-F93L mice were analyzed using histochemistry, immunohistochemistry, and immunoblot. Mouse functional strength measures included forelimb grip strength and inverted wire hang.ResultsDNAJB6 inactivation leads to the accumulation of sarcomeric proteins and hypertrophic myotubes with an enhanced fusion index. The increased fusion in DNAJB6 KO myotubes correlates with diminished glycogen synthase kinase-β (GSK3β) activity. In contrast, LGMD1D mutations in DNAJB6 enhance GSK3β activation and suppress β-catenin and NFAT3c signaling. GSK3β inhibition with lithium chloride improves muscle size and strength in an LGMD1D preclinical mouse model.ConclusionsOur results suggest that DNAJB6 facilitates protein quality control and negatively regulates myogenic signaling. In addition, LGMD1D-associated DNAJB6 mutations inhibit myogenic signaling through augmented GSK3β activity. GSK3β inhibition with lithium chloride may be a therapeutic option in LGMD1D.