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Query: UMLS:C0015672 (fatigue)
 51,768 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Muscular exercise results in an increased production of free radicals and other forms of reactive oxygen species (ROS). Further, developing evidence implicates cytotoxins as an underlying etiology of exercise-induced stimuli in muscle redox status, which could result in muscle fatigue and/or injury. Two major classes of endogenous protective mechanisms (enzymatic and nonenzymatic antioxidants) work together to reduce the harmful effects of oxidants in the cell. This study examined the effects of acute physical exercise on the enzymatic antioxidant systems of different athletes and comparison was made to the mechanism of action of three main antioxidant enzymes in the blood. Handball players (n = 6), water-polo players (n = 20), hockey players (n = 22), basketball players (n = 24), and a sedentary control group (n = 10 female and n = 9 male) served as the subjects of this study. The athletes were divided into two groups according to the observed changes of activity of superoxide dismutase enzyme. The antioxidant enzyme systems were characterized by catalase (CAT), glutathione-peroxidase (GPX), and superoxide-dismutase (SOD) and measured by spectrophotometry. An important finding in the present investigation is that when the activities of SOD increased, the activities of GPX and CAT increased also and this finding related to the physical status of interval-trained athletes. Positive correlation between SOD and GPX activities was observed (r = 0.38 females, r = 0.56 males; p < 0.05). We have observed that the changes in the primary antioxidant enzyme systems of athletes are sport specific, and different from control subjects. Presumably, with interval-trained athletes, hydrogen-peroxide is significantly eliminated by glutathione-peroxidase. From these results it can be concluded that the blood redox status should be taken into consideration when establishing a fitness level for individual athletes.
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PMID:Antioxidant status of interval-trained athletes in various sports. 1647 56

Free radicals are reactive compounds that are naturally produced in the human body. They can exert positive effects (e.g. on the immune system) or negative effects (e.g. lipids, proteins or DNA oxidation). To limit these harmful effects, an organism requires complex protection - the antioxidant system. This system consists of antioxidant enzymes (catalase, glutathione peroxidase, superoxide dismutase) and non-enzymatic antioxidants (e.g. vitamin E [tocopherol], vitamin A [retinol], vitamin C [ascorbic acid], glutathione and uric acid). An imbalance between free radical production and antioxidant defence leads to an oxidative stress state, which may be involved in aging processes and even in some pathology (e.g. cancer and Parkinson's disease). Physical exercise also increases oxidative stress and causes disruptions of the homeostasis. Training can have positive or negative effects on oxidative stress depending on training load, training specificity and the basal level of training. Moreover, oxidative stress seems to be involved in muscular fatigue and may lead to overtraining.
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PMID:Oxidative stress : relationship with exercise and training. 1657 58

Aged garlic extract (AGE) has recently received attention as a potent anti-fatigue agent. The principal aim of this study was to elucidate the mechanism responsible for the ameliorating effect of AGE on physical fatigue in rats caused by repeated endurance exercise on a mechanical treadmill apparatus. Rats were subjected to endurance exercise 5 times per week for 4 weeks. AGE at a dosage of 2.86 g/kg was administrated to rats 30 min before every exercise. Succinate dehydrogenase (SDH) activity in the gastrocnemius and soleus muscles and superoxide dismutase (SOD) activity, nitric oxide (NO) metabolites, and lactic acid concentration in plasma were evaluated as biomarkers of physical fatigue. SDH activity was increased 2-4-fold by repeated endurance exercise in comparison with unexercised (intact) rats, and AGE further up-regulated this activity by 40%. SOD activity was increased 5-fold, whereas AGE maintained it at a level equivalent to that in intact rats. Levels of NO metabolites were slightly decreased, whereas AGE enhanced them 2-fold. Lactic acid concentration was not changed in any of the groups. These results indicate that AGE may facilitate the turnover of aerobic glucose metabolism, attenuate oxidative stress, and promote oxygen supply based on vasodilation, suggesting that AGE ameliorates the various impairments associated with physical fatigue.
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PMID:Aged garlic extract ameliorates physical fatigue. 1665 27

Two groups, each containing 10 young healthy male students, participated in the study. One group breathed 70% O2 after exercise (70% O2 group) while the other group breathed normal air (Normal air group) after exercise. The results of the study show the following: (1) in both groups, the Monodehydyoxygenbate (MDA) in erythrocyte (RBC) and serum, and superoxide dismutase (SOD) and glutathione Peroxidas (GSH-px) in serum were significantly higher immediately after exercise than at rest; (2) the MDA in RBC and serum were significantly higher in the Normal air group than in the 70% O2 group for 30 minutes after exercise; and (3) the SOD in serum and GSH-px in blood and serum were significantly higher in the 70% O2 group than in the Normal air group for 30 minutes after exercise. We suggest that the effects of inhaling 70% O2 could prevent fatigue from antagonizing free radicals damage, hastening removal of free radicals, which would facilitate recovery from fatigue.
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PMID:Effects of inhalation of oxygen on free radical metabolism and oxidative, antioxidative capabilities of the erythrocyte after intensive exercise. 1686 36

Skeletal muscle often shows a delayed force recovery after fatiguing stimulation, especially at low stimulation frequencies. In this study we focus on the role of reactive oxygen species (ROS) in this fatigue-induced prolonged low-frequency force depression. Intact, single muscle fibres were dissected from flexor digitorum brevis (FDB) muscles of rats and wild-type and superoxide dismutase 2 (SOD2) overexpressing mice. Force and myoplasmic free [Ca(2+)] ([Ca(2+)](i)) were measured. Fibres were stimulated at different frequencies before and 30 min after fatigue induced by repeated tetani. The results show a marked force decrease at low stimulation frequencies 30 min after fatiguing stimulation in all fibres. This decrease was associated with reduced tetanic [Ca(2+)](i) in wild-type mouse fibres, whereas rat fibres and mouse SOD2 overexpressing fibres instead displayed a decreased myofibrillar Ca(2+) sensitivity. The SOD activity was approximately 50% lower in wild-type mouse than in rat FDB muscles. Myoplasmic ROS increased during repeated tetanic stimulation in rat fibres but not in wild-type mouse fibres. The decreased Ca(2+) sensitivity in rat fibres could be partially reversed by application of the reducing agent dithiothreitol, whereas the decrease in tetanic [Ca(2+)](i) in wild-type mouse fibres was not affected by dithiothreitol or the antioxidant N-acetylcysteine. In conclusion, we describe two different causes of fatigue-induced prolonged low-frequency force depression, which correlate to differences in SOD activity and ROS metabolism. These findings may have clinical implications since ROS-mediated impairments in myofibrillar function can be counteracted by reductants and antioxidants, whereas changes in SR Ca(2+) handling appear more resistant to interventions.
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PMID:Reactive oxygen species and fatigue-induced prolonged low-frequency force depression in skeletal muscle fibres of rats, mice and SOD2 overexpressing mice. 1800 75

Now peptides achieve distinct advantages over protein in biological application because of its quick and easy absorption, low power, and high activity. Some bioactive peptides had been developed to be used in the management of exercise-related disorders. In this study, we investigated whether the decapeptide CMS001 (Pro-Thr-Thr-Lys-Thr-Tyr-Phe-Pro-His-Phe) isolated from pig spleen had anti-fatigue effects. Male Balb/c mice were administered CMS001 (20 microg/(kgd)(-1) or 5 microg/(kgd)(-1) for 30 d, intraperitoneal injections) and tested in an exhaustive swim time task. In order to examine the mechanisms of CMS001 anti-fatigue effects, we analyzed liver glycogen stores, blood urea nitrogen (BUN) levels, lactic acid levels, ultrastructural integrity, and levels of both a free radical metabolite and an anti-oxidant enzyme. CMS001 treatment prolonged exhaustive swim time, increased liver glycogen levels, reduced BUN levels, and decreased accumulation of lactic acid in the blood, relative to mice injected with only saline. Examination of the ultrastructure of mitochondria and sarcoplasmic reticulum in skeletal and cardiac muscle of CMS001-treated and control mice revealed that CMS001 can reduce the damage to cardiac and skeletal muscle caused by an exhaustive swim challenge, such that the structure of most tissue specimens were normal in the peptide-treated group. Furthermore the free radical analysis after acute exercise indicated that CMS001 treatment decreased malondialdehyde (MDA) and increased superoxide dismutase (SOD) levels. The present findings indicate that the spleen-derived peptide CMS001 has anti-fatigue effects in mice, and further suggest that the mechanism may involve reduction of tissue damaging free radicals in muscle tissues.
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PMID:The decapeptide CMS001 enhances swimming endurance in mice. 1844 Jun 69

We tested the hypothesis that reactive oxygen species (ROS) and inflammatory mediators affect transduction properties of muscle spindles. In rats, muscle spindles response to high-frequency vibration (HFV) was recorded before and after (1) injection of hydrogen peroxide (H2O2) in control rats and animals pre-treated with diclofenac (anti-inflammatory substance), (2) injection of bradykinin and (3) fatigue induced by muscle stimulation (MS) in control rats and rats receiving diclofenac, superoxide dismutase (SOD) or H2O2. Muscular oxidative stress and inflammation induced by H2O2 or MS were assessed by measurements of isoprostanes and IL-6 levels. In control rats, H2O2, bradykinin and MS significantly enhanced the HFV response. Pre-treatment with SOD abolished the post-MS-enhanced HFV response whereas diclofenac lowered the peak HFV response to MS and H2O2. H2O2 injection and MS elicited significant and similar increases in isoprostanes and IL-6. We report a direct modulation of muscle spindles mechanosensitivity by ROS and inflammatory mediators.
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PMID:Reactive oxygen species and inflammatory mediators enhance muscle spindles mechanosensitivity in rats. 1884 83

20(R)-ginsenoside Rg3 (20(R)-Rg3) has shown multiple pharmacological activities and been considered as one of the most promising approaches for fatigue treatment. However, 20(R)-Rg3 has a low bioavailability after oral administration in human due to the first-pass effect. Recently, nasal route has gained increasing interest as it can avoid first-pass effect for its lower enzymatic activity compared with the gastrointestinal tract and liver. In order to provide an animal experimental evidence of 20(R)-Rg3 intranasal administrated preparation, the anti-fatigue effect of 20(R)-Rg3 after intranasal administration was investigated. Two weeks after 20(R)-ginsenoside Rg3 was administrated intranasally to mice at three different doses, the anti-fatigue effect of 20(R)-Rg3 was evaluated by the weight-loaded swimming test and biochemical parameters related to fatigue, such as serum urea nitrogen (SUN), lactic dehydrogenase (LDH), superoxide dismutase (SOD), malondialdehyde (MDA), blood lactic acid (LA) and hepatic glycogen. The results showed that compared with the negative control group, the intermediate-dose and the high-dose groups significantly prolonged the weight-loaded swimming time (p<0.05; p<0.01), and also increased the hepatic glycogen levels (p<0.05); SUN levels were decreased considerably in three 20(R)-Rg3-treated groups (p<0.01). In addition, the low-dose group obviously decreased the content of blood LA (p<0.05). However, the levels of LDH, SOD and MDA did not show a significant change. Our results predicted a benefit of 20(R)-Rg3 as an anti-fatigue treatment by intranasal administration. The mechanism was related to the increase of the storage of hepatic glycogen, and the decrease of the accumulation of metabolite such as lactic acid and serum urea nitrogen.
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PMID:The anti-fatigue effect of 20(R)-ginsenoside Rg3 in mice by intranasally administration. 1898 67

Ferulic acid was orally administered to mice in order to investigate its effects on exercise endurance capacity. When a single administration of ferulic acid was given to the mice in an adjustable-current water pool, the duration of exhaustive swimming was longer than that exhibited by the mice in the control group. Also, when the mice were exhaustively exercised for 3 consecutive days, no change in swimming time was found in the ferulic acid-administered group on the final day, and a large decrease in the untreated mice. Administration of ferulic acid efficiently activated the hepatic antioxidative defense system during exercise. The mice that received ferulic acid showed significant increases in the activity of hepatic antioxidant enzymes such as superoxide dismutase, catalase, and glutathione-S-transferase. Furthermore, an increased glutathione level was observed, while the malondialdehyde content was reduced. These results suggest that ferulic acid possesses stimulatory effects that can enhance exercise endurance capacity and reduce fatigue by elevating antioxidative potentials.
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PMID:Stimulatory effects of ferulic acid on endurance exercise capacity in mice. 1950 23

Three decades after the coining of the term chronic fatigue syndrome, the diagnosis of this illness is still symptom based and the aetiology remains elusive. Chronic fatigue syndrome pathogenesis seems to be multifactorial and the possible involvement of immune system is supported. The present study was designed to evaluate the effects of the epigallocatechin gallate in a mouse model of immunologically induced chronic fatigue. On 19th day, after lipopolysaccharide/Brucella abortus administration, the mice showed significant increase in immobility period, post swim fatigue and thermal hyperalgesia. Behavioral deficits were coupled with enhanced oxidative-nitrosative stress as evident by increased lipid peroxidation, nitrite levels and decreased endogenous antioxidant enzymes (superoxide dismutase, reduced glutathione and catalase) and inflammation (increased levels of tumor necrosis factor-alpha and tissue growth factor-beta). Chronic treatment with epigallocatechin gallate restored these behavioral and biochemical alterations in mice. The present study points out towards the beneficial effect of epigallocatechin gallate in the amelioration of chronic fatigue syndrome and thus may provide a new, effective and powerful strategy to treat chronic fatigue syndrome.
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PMID:Epigallocatechin gallate ameliorates chronic fatigue syndrome in mice: behavioral and biochemical evidence. 1964 48


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