Oxidative DNA damage in human peripheral leukocytes induced by massive aerobic exercise

Effect of Stanozolol and/or Cannabis Abuse on Hypertrophic Mechanism and Oxidative Stress of Male Albino Rat Cardiac Tissue in Relation to Exercise: A Sport Abuse Practice

Adolescents commonly co-abuse many drugs including anabolic androgenic steroids either they are athletes or non-athletes. Stanozolol is the major anabolic used in recent years and was reported grouped with cannabis. The current study aimed at evaluating the biochemical and histopathological changes related to the hypertrophic effects of stanozolol and/or cannabis whether in condition of exercise practice or sedentary conditions. Adult male Wistar albino rats received either stanozolol (5 mg/kg, s.c), cannabis (10 mg/kg, i.p.), and a combination of both once daily for two months. Swimming exercise protocol was applied as a training model. Relative heart weight, oxidative stress biomarkers, cardiac tissue fibrotic markers were evaluated. Left ventricular morphometric analysis and collagen quantification was done. The combined treatment exhibited serious detrimental effects on the heart tissues. It increased heart tissue fibrotic markers (Masson's trichrome stain (p < 0.001), cardiac COL3 (p < 0.0001), and VEGF-A (p < 0.05)), lowered heart glutathione levels (p < 0.05) and dramatically elevated oxidative stress (increased malondialdehyde (p < 0.0001) and 8-OHDG (p < 0.0001)). Training was not ameliorating for the observed effects. Misuse of cannabis and stanozolol resulted in more hypertrophic consequences of the heart than either drug alone, which were at least largely assigned to oxidative stress, heart tissue fibrotic indicators, histological alterations, and morphometric changes.

Antioxidants and Sports Performance

The role of reactive oxygen species and antioxidant response in training adaptations and sports performance has been a large issue investigated in the last few years. The present review aims to analyze the role of reactive oxygen species and antioxidant response in sports performance. For this aim, the production of reactive oxygen species in physical activities, the effect of reactive oxygen species on sports performance, the relationship between reactive oxygen species and training adaptations, inflammation, and the microbiota, the effect of antioxidants on recovery and sports performance, and strategies to use antioxidants supplementations will be discussed. Finally, practical applications derived from this information are discussed. The reactive oxygen species (ROS) production during physical activity greatly influences sports performance. This review concludes that ROS play a critical role in the processes of training adaptation induced by resistance training through a reduction in inflammatory mediators and oxidative stress, as well as appropriate molecular signaling. Additionally, it has been established that micronutrients play an important role in counteracting free radicals, such as reactive oxygen species, which cause oxidative stress, and the effects of antioxidants on recovery, sports performance, and strategies for using antioxidant supplements, such as vitamin C, vitamin E, resveratrol, coenzyme Q10, selenium, and curcumin to enhance physical and mental well-being.

Pure Juice Supplementation: Its Effect on Muscle Recovery and Sports Performance

Strenuous exercise causes increased production of reactive oxygen species (ROS), creating an imbalance between ROS and antioxidants. The reduced antioxidant defence leads to defective elimination of ROS and consequently, delayed-onset muscle soreness (DOMS). DOMS due to exhaustive or prolonged exercise typically peaks between 24 h and 72 h after exercise results in soreness, inflammation, pain and decreased muscle function. As a result, muscle strength will be reduced progressively and this situation might be detrimental to one's athletic performance, especially amidst competition season. Therefore, supplementation to improve muscle recovery and sports performance has become a common practice among athletes. However, it is suggested to consume natural-based fruit-derived antioxidants as a more effective and safe nutritional strategy. Fruits containing a high amount of polyphenol protect muscle cells from excessive and harmful ROS due to their anti-inflammatory and antioxidant characteristics. To date, there are several expended studies on the consumption of supplements from various antioxidant-rich fruits to provide evidence on their effectiveness, giving better solutions and wider choices of supplementation to the athletes. Therefore, this review aims to provide a comprehensive overview of nutritional standpoint from previous literature on the effect of fruit juices supplementation on muscle recovery and sports performance.

Effect of 8-week high-intensity intermittent running exercise and weight training on muscle and DNA damage in male and female ski major college students

This study assessed changes in blood muscle damage indicators and DNA damage indicators in lymph and urine after 8 weeks of high-intensity intermittent running and weight training in male and female college students majoring in skiing. This study aimed to find an effective training method by investigating differences in the effectiveness between men and women. A total of 20 male and female ski major college students conducted short-term high-intensity intermittent running and weight training in the morning and afternoon, respectively, 3 days a week for 8 weeks for 24 times in total. After 8 weeks of high-intensity intermittent running and weight training, changes in DNA damage indicators in the lymph and urine and muscle damage indicators in the blood were analyzed. The creatine kinase level significantly differed at rest pre-graded exercise testing (GXT) and 60 min of recovery post-GXT after training from that before training between the male and female groups. Although lactate dehydrogenase (LDH) levels decreased in both groups over time, no significant differences in LDH were found between the two groups. Second, DNA 8-hydroxydeoxyguanosine (8-OHdG) in the lymph was significantly different between the two groups at rest pre-GXT and 60 min of recovery post-GXT. 8-OHdG in the urine was significantly lower in the female group only at 60 min of recovery post-GXT. Partial sex differences were found in the reduction of muscle damage and DNA damage after 8 weeks of high-intensity intermittent running and weight training.

Associations of urinary metabolites of oxidized DNA and RNA with the incidence of diabetes mellitus using UPLC-MS/MS and ELISA methods

BACKGROUND

To evaluate the association of urinary oxidized guanine/guanosine (OxGuo) levels with incident type 2 diabetes (T2D) among older adults.

METHODS

A nested case-control design was applied with 440 cases of incident T2D and 440 controls, randomly sampled from all 65-75 year-old study participants of the ESTHER study, which is a population-based German cohort study with 14 years of follow-up. Analyses of 8-hydroxy-2'-deoxyguanosine (8-oxo-dGuo; DNA oxidation product) and 8-hydroxyguanosine (8-oxo-Guo; RNA oxidation product) were measured by ultra-performance liquid chromatography tandem-mass spectrometry (UPLC-MS/MS). The sum of the two OxGuo molecule concentrations was calculated and called OxGuo-UPLC-MS/MS. The corresponding OxGuo-ELISA levels were measured by Cayman's DNA/RNA oxidative damage ELISA, which detects a mix of 8-oxo-dGuo, 8-oxo-Guo and one other OxGuo molecule. Logistic regression was applied and models were adjusted for age, sex, BMI, HbA_1c, and C-reactive protein levels.

RESULTS

8-oxo-dGuo and 8-oxo-Guo were highly correlated with each other (r = 0.642) and weakly correlated with OxGuo-ELISA (r = 0.22 and r = 0.14, respectively). OxGuo-ELISA levels were statistically significant associated with T2D incidence (odds ratio (OR) and 95% confidence interval [95%CI] for comparison of top and bottom quartile: 1.77 [1.14; 2.76]). In contrast, the ORs did not increase stepwise from quartile 2 to 4 for neither 8-oxo-Guo, 8-oxo-dGuo levels nor OxGuo-UPLC-MS/MS and comparisons of top and bottom quartile were not statistically significant. In a post-hoc analysis comparing bottom quartile 1 with a combined group of quartile 2-4, the association of OxGuo-UPLC-MS/MS with T2D incidence reached statistical significance (OR [95%CI]: 0.66 [0.46; 0.96]) and was very similar with the one obtained for OxGuo-ELISA (OR [95%CI]: 0.66 [0.45; 0.95]).

CONCLUSIONS

Although only the measurements of the DNA/RNA oxidative damage ELISA kit of Cayman were statistically significantly associated with T2D incidence in the main analysis, confidence intervals overlapped and the post-hoc analysis showed that results for OxGuo-UPLC-MS/MS were quite comparable.

Regular, Intense Exercise Training as a Healthy Aging Lifestyle Strategy: Preventing DNA Damage, Telomere Shortening and Adverse DNA Methylation Changes Over a Lifetime

Exercise training is one of the few therapeutic interventions that improves health span by delaying the onset of age-related diseases and preventing early death. The length of telomeres, the 5'-TTAGGG n -3' tandem repeats at the ends of mammalian chromosomes, is one of the main indicators of biological age. Telomeres undergo shortening with each cellular division. This subsequently leads to alterations in the expression of several genes that encode vital proteins with critical functions in many tissues throughout the body, and ultimately impacts cardiovascular, immune and muscle physiology. The sub-telomeric DNA is comprised of heavily methylated, heterochromatin. Methylation and histone acetylation are two of the most well-studied examples of the epigenetic modifications that occur on histone proteins. DNA methylation is the type of epigenetic modification that alters gene expression without modifying gene sequence. Although diet, genetic predisposition and a healthy lifestyle seem to alter DNA methylation and telomere length (TL), recent evidence suggests that training status or physical fitness are some of the major factors that control DNA structural modifications. In fact, TL is positively associated with cardiorespiratory fitness, physical activity level (sedentary, active, moderately trained, or elite) and training intensity, but is shorter in over-trained athletes. Similarly, somatic cells are vulnerable to exercise-induced epigenetic modification, including DNA methylation. Exercise-training load, however, depends on intensity and volume (duration and frequency). Training load-dependent responses in genomic profiles could underpin the discordant physiological and physical responses to exercise. In the current review, we will discuss the role of various forms of exercise training in the regulation of DNA damage, TL and DNA methylation status in humans, to provide an update on the influence exercise training has on biological aging.

The Effects of Combined Physical Exercise on Serum Redox Biomarkers and Leukocyte DNA Damage of Obese Women

Obesity is usually linked to oxidative stress, which can lead to damage to biomolecules. The combination of aerobic and strength exercises seems to induce health benefits in obese individuals, but little is known about the effects of combined physical exercise on redox homeostasis and DNA damage in this population. Thus, the aim of the current study was to determine the effects of 16 weeks of combined physical exercise on biomarkers of oxidative stress and DNA damage in obese women. 17 obese women underwent 16 weeks of a combined physical training program, 3 times per week. Anthropometric and biochemical parameters, serum superoxide dismutase (SOD) and glutathione peroxidase activity, plasma 8-isoprostane levels, and DNA and chromosomal damage were evaluated before and after physical training. Combined physical exercise training decreased body weight (83.2 ± 9.6 vs. 80.2 ± 9.6 kg), body mass index (33.8 ± 3.6 vs. 32.6 ± 3.7 kg·m-2), body fat (40.2 ± 2.6 vs. 39.0 ± 3.2%), and waist circumference (99.3 ± 9.4 vs. 94.1 ± 8.8 cm), while the fat-free mass was augmented (59.9 ± 2.9 vs. 60.7 ± 3.1 kg). Moreover, blood glucose reduced (113.5 ± 29.6 vs. 107.3 ± 28.9 mg/dL) along with high-density lipoprotein (54.6 ± 18.1 vs. 59.0 ± 18.8 mg/dL), TSH (2.1 ± 1.1 vs. 2.6 ± 1.2 mIU/mL), and free T4 (0.9 ± 0.1 vs. 1.12 ± 0.2 ng/dL) increase after physical exercise training. Plasma 8-isoprostane levels (17.24 ± 7.9 vs. 29.11 ± 17.44 pg/mL) and DNA damage (34.16 ± 7.1 vs. 45.96 ± 5.8% DNA in tail) were also higher after physical training. No changes were observed in chromosomal damage levels. These results suggest that 16 weeks of combined exercise training 3 times per week is effective in reducing body fat but also increases oxidative stress and DNA damage in obese women.

Supplementation with Vitamins C and E and Exercise-Induced Delayed-Onset Muscle Soreness: A Systematic Review

Muscle damage induced by exercise may have several consequences such as delayed-onset muscle soreness, a side-effect of the release of free radicals during oxidative stress. To mitigate the oxidative stress cascade, the oral intake of antioxidants has been assessed by several research groups. This review examines whether supplementation with vitamin C and/or vitamin E is able to prevent or attenuate delayed-onset muscle soreness after eccentric exercise. The PubMed, Web of Science, Medline, and Embase databases were searched to identify studies meeting the inclusion criteria: primary randomized control trials, healthy male and female participants aged 16–80 years, and an intervention consisting of the intake of vitamin C and/or vitamin E without other supplements plus a controlled eccentric exercise regimen. Further requirements were the measurement of muscle soreness or markers of delayed-onset muscle soreness. All original full-text articles in English or translated into English published from January 2000 to June 2020 were considered for this review. Fourteen studies were finally identified, including 280 participants, 230 men, and 50 women aged 16–30 years. All participants were healthy individuals with different starting levels of physical activity. Supplementation was acute in two studies and chronic in 12, and its consisted of vitamin C in eight studies, vitamin E in two studies, and both in four studies. Only in 3 of the 14 studies was muscle soreness found to be significantly reduced in response to vitamin C and/or vitamin E supplementation at all time points when compared to the placebo group. Despite some studies showing the beneficial effects of chronic supplementation with these vitamins on muscle soreness manifesting 24–72 h after eccentric exercise, the evidence is so far insufficient to confirm that the intake of antioxidant vitamins is able to minimize delayed-onset muscle soreness in this context.

Differential time responses in inflammatory and oxidative stress markers after a marathon: An observational study

Acute and adaptive changes in systemic markers of oxidatively generated nucleic acid modifications (i.e., 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) and 8-oxo-7,8-dihydroguanosine (8-oxoGuo)) as well as inflammatory cytokines (i.e., C-reactive protein, interleukin-6, interleukin-10, and tumour necrosis factor alpha), a liver hormone (i.e., fibroblast growth factor 21 (FGF21)), and bone metabolism markers (sclerostin, osteocalcin, C-terminal telopeptide, and N-terminal propeptide of type 1 procollagen) were investigated following a marathon in 20 study participants. Immediate changes were observed in inflammatory cytokines, FGF21, and bone metabolism markers following the marathon. In contrast, no immediate changes in urinary excretion of 8-oxodG and 8-oxoGuo were evident. Four days after the marathon, decreased urinary excretion of 8-oxodG (-2.9 (95% CI -4.8;-1.1) nmol/24 h, P < 0.01) and 8-oxoGuo (-5.8 (95% CI -10.3;-1.3) nmol/24 h, P = 0.02) was observed. The excretion rate of 8-oxodG remained decreased 7 days after the marathon compared to baseline (-2.3 (95%CI -4.3;-0.4) nmol/24 h, P = 0.02), whereas the excretion rate of 8-oxoGuo was normalized. In conclusion marathon participation immediately induced a considerable inflammatory response, but did not increase excretion rates of oxidatively generated nucleic acid modifications. In fact, a delayed decrease in oxidatively generated nucleic acid modifications was observed suggesting adaptive antioxidative effects following exercise.

ABBREVIATIONS

8-oxodG: 8-oxo-7,8-dihydro-2'-deoxyguanosine; 8-oxoGuo: 8-oxo-7,8-dihydroguanosine; CI: confidence interval; CTX: C-terminal telopeptide of type 1 collagen; DXA: dual-energy X-ray absorptiometry; ELISA: enzyme-linked immunosorbent assay; FGF21: Fibroblast growth factor 21; h: hour; hsCRP: high sensitivity C-reactive protein; IL: interleukin; IQR: interquartile range; MS: mass spectrometry: P1NP: N-terminal propeptide of type 1 procollagen; TNFα: tumour necrosis factor alpha; UPLC: ultra-performance liquid chromatography.

LDH isoenzyme 5 is an index of early onset muscle soreness during prolonged running

BACKGROUND

Muscle soreness is also induced during prolonged running such as a full marathon, and muscle soreness and increased damage markers are detected immediately after such a running. We named this muscle soreness, early onset muscle soreness (EOMS). Additionally, lactate dehydrogenase (LDH) level which has some isoenzyme is increased immediately after prolonged exercise. However, it is unclear that EOMS is related to muscle damage markers on prolonged running. This study aimed to determine at which point EOMS, and muscle damage markers are related to EOMS during prolonged running.

METHODS

We studied 11 male subjects who habitually perform aerobic exercise. They ran 30 km at 90% of ventilatory threshold intensity. Every 10 km, we estimated perceived muscle soreness, and sampled blood to measure muscle and liver damage, inflammation, and oxidative stress (d-ROM and BAP) markers.

RESULTS

Muscle soreness score lower limbs were significantly appeared at 20 km compared to that at 0 km. Serum lactate dehydrogenase (LDH) level increased at 30 km compared to that at 0 km. LDH isoenzymes 3, 4, and 5, and neutrophils significantly increased at 30 km compared to those at 0 km. Serum LDH isoenzyme 5 and change in aspartate aminotransferase significantly increased at 20 km. In addition, there was a significant correlation between the thigh NRS and amount of serum LDH isoenzyme 5 from 0 km to 20 km. d-ROM and BAP increased at 10 km compared to those at 0 km.

CONCLUSIONS

EOMS started to occur at 20 km during a 30 km running task. Our data suggest that LDH isoenzyme 5 is a marker of occurrence in EOMS during prolonged running.

Relationship between early-onset muscle soreness and indirect muscle damage markers and their dynamics after a full marathon

Background/Objective

Muscle soreness and damage occurs after completing a full marathon. Here we refer to muscle soreness induced by prolonged running as early-onset muscle soreness (EOMS) because muscle soreness and damage markers induced after prolonged running are different from delayed-onset muscle soreness (DOMS) and muscle damage markers induced after eccentric contraction, such as resistance exercise. The dynamics and relationship between muscle damage markers and EOMS are unclear; therefore, in this study, we aimed to elucidate the relationship between EOMS and indirect muscle damage markers, and their dynamics after a full marathon.

Methods

The following measurements were performed in 19 subjects who completed a full marathon: perceived muscle soreness (using a numeric rating scale), thigh circumference (CIR), hip joint range of motion (ROM), jump height (JH) and muscle damage marker activities in the blood (CK, AST, LDH, ALD) before (Pre), after (Post) and every day for 4 days after a full marathon (D1−4).

Results

EOMS was induced, as determined by the numeric rating scale score peaking immediately after a full marathon. ROM and JH significantly decreased and all muscle damage markers significantly increased after a full marathon. Serum CK and AST peaked at D1. Serum LDH and ALD peaked at Post and D3. Each marker showed different dynamics. CIR significantly decreased after a full marathon.

Conclusion

Muscle soreness peaked and muscle damage markers in the blood showed different dynamics after a full marathon. In other words, this is different from DOMS.

DNA Damage Following Acute Aerobic Exercise: A Systematic Review and Meta-analysis

BACKGROUND

Exercise is widely recognised for its health enhancing benefits. Despite this, an overproduction of reactive oxygen and nitrogen species (RONS), outstripping antioxidant defence mechanisms, can lead to a state of (chronic) oxidative stress. DNA is a vulnerable target of RONS attack and, if left unrepaired, DNA damage may cause genetic instability.

OBJECTIVE

This meta-analysis aimed to systematically investigate and assess the overall effect of studies reporting DNA damage following acute aerobic exercise.

METHODS

Web of Science, PubMed, MEDLINE, EMBASE, and Scopus were searched until April 2019. Outcomes included (1) multiple time-points (TPs) of measuring DNA damage post-exercise, (2) two different quantification methods (comet assay and 8-oxo-2'-deoxyguanosine; 8-OHdG), and (3) protocols of high intensity (≥ 75% of maximum rate of oxygen consumption; VO2-max) and long distance (≥ 42 km).

RESULTS

Literature search identified 4316 non-duplicate records of which 35 studies were included in the meta-analysis. The evidence was strong, showcasing an increase in DNA damage immediately following acute aerobic exercise with a large-effect size at TP 0 (0 h) (SMD = 0.875; 95% CI 0.5, 1.25; p < 0.05). When comparing between comet assay and 8-OHdG at TP 0, a significant difference was observed only when using the comet assay. Finally, when isolating protocols of long-distance and high-intensity exercise, increased DNA damage was only observed in the latter. (SMD = 0.48; 95% CI - 0.16, 1.03; p = 0.15 and SMD = 1.18; 95% CI 0.71, 1.65; p < 0.05 respectively).

CONCLUSIONS

A substantial increase in DNA damage occurs immediately following acute aerobic exercise. This increase remains significant between 2 h and 1 day, but not within 5-28 days post-exercise. Such an increase was not observed in protocols of a long-distance. The relationship between exercise and DNA damage may be explained through the hormesis theory, which is somewhat one-dimensional, and thus limited. The hormesis theory describes how exercise modulates any advantageous or harmful effects mediated through RONS, by increasing DNA oxidation between the two end-points of the curve: physical inactivity and overtraining. We propose a more intricate approach to explain this relationship: a multi-dimensional model, to develop a better understanding of the complexity of the relationship between DNA integrity and exercise.

α-Tocopherol Protects the Heart, Muscles, and Testes from Lipid Peroxidation in Growing Male Rats Subjected to Physical Efforts

The effect of α-tocopherol supplementation on adaptation to training is still equivocal. The aim of the study was to determine the effect of training and α-tocopherol supplementation on α-tocopherol and thiobarbituric acid reactive substance (TBARS) concentration in the rat liver, heart, muscles, and testes. Male Wistar rats (n = 32) were divided into four groups (nonsupplemented, not trained—C; nonsupplemented, trained—CT; supplemented, not trained—E; supplemented and trained—ET). During the 14-day experimental period, 2 mg/d of vitamin E as α-tocopherol acetate was administered to the animals (groups E and ET). Rats in the training group (CT and ET) were subjected to 15 minutes of treadmill running each day. The α-tocopherol levels in rat tissues were assessed using high-performance liquid chromatography (HPLC). Lipid peroxides were determined by TBARS spectrophotometric method. α-Tocopherol had a significant impact on α-tocopherol concentration in all tissues. Training increased the α-tocopherol concentration in the heart and muscles but reduced it in the liver. Training also caused increased lipid peroxidation in the muscles, heart, and testes; but a higher α-tocopherol content in tissues reduced the TBARS level. The main finding of the study is that impaired α-tocopherol status and its adequate intake is needed to maintain optimal status to prevent damage to the skeletal and cardiac muscles as well as the testes in growing individuals.

Traditional Indian sports - A case-control study on Kho Kho players investigating genomic instability and oxidative stress as a function of metabolic genotypes

The beneficial effects of physical exercise regularly for overall well being, or for recreational or professional purposes are widely accepted in clinical practice and have from time immemorial been the reasons for performing traditional sports. On the contrary, there is also evidence implying increased oxidative stress and genetic damage from intensive exercising. Depending on the intensity, time, frequency and characteristics of exercises, there can be differential induction of oxidative stress and provocation of oxidation of cellular macromolecules (including DNA) and cellular dysfunction which can likely accumulate with age, physical attributes and increase the susceptibility to disease on one hand, while stimulating cell signalling pathways leading to cell adaptation and improved resistance to stress, on the other. In order to observe if continuous sports activities as in Kho Kho increase oxidation capacity, which can also provoke oxidation of cellular macromolecules, the effects on oxidative/antioxidant changes and DNA damage in professional Kho Kho players modulated by individual genetic differences were assessed. Kho Kho, a traditional Indian game of ‘Tag’, is an all-time favourite which requires endurance, agility and strength. Healthy Kho Kho players (20.27 ± 0.28 y; sports age 6.78 ± 0.52 y) and controls (20.90 ± 0.45 y) were matched for age, gender, BMI, VO₂ max (maximal oxygen uptake), frequency of GSTT1 (present/null), M1 (present/null), SOD2 (C199T) polymorphisms but differed for variant allele frequencies of GSTP1 (A313G) and SOD2 (C47T). Players compared to controls had significantly increased levels of DNA damage (1.8x, 44.66 ± 1.68 vs. 23.85 ± 1.79 μm, p = 0.000), lipid (MDA) peroxidation (2x, 1.72 ± 0.06 vs. 0.83 ± 0.16 μmol/l, p = 0.000) and total antioxidant capacity (1.09x, 1.69 ± 0.06 vs. 1.11 ± 0.03 mmol Trolox equivalent/l, p = 0.000) but with no differences for SOD activity (94.99 ± 2.42 vs. 93.36 ± 2.54 U/ml, p = 0.935). These results suggest that the players have increased genetic damage and oxidative stress probably from the intense physical activity in the absence of other exposure(s) as other attributes were comparable in the study group. The players may therefore be at increased risk for susceptibility to cancer, various diseases and precocious age-related changes and should be sensitized to health risks related to regular intensive physical exercise.

Training Induced Oxidative Stress-Derived DNA and Muscle Damage in Triathletes

Objective

Regular moderate-intensity exercise has beneficial health effects, whereas regular strenuous exercise increases the production of oxidants that may lead to DNA, skeletal, and cardiac muscle damages. Triathletes experience strenuous muscular activity both during competition and training, being at risk of developing these tissue damages. The objective of the present study was to estimate DNA, skeletal, and cardiac muscle damages using blood biomarkers, 8-hydroxy-2'-deoxyguanosine (8-OHdG), myoglobin, and cardiac troponin I (cTnI) among young triathletes.

Materials and Methods

Age-matched seven male and seven female triathletes were recruited for the study. They were on a standardized training regimen and on average competed in at least one endurance event every month for the past 3-4 years. Serum biomarkers were measured using enzyme-linked immunosorbent assay at the start and at end of the racing season.

Results

Both male and female triathletes showed a statistically significant increase in 8-OHdG. A similar pattern of increase was seen with serum myoglobin, which was not statistically significant in both male and female triathletes. cTnI levels did not show any change in both sexes.

Conclusion

Our study shows that there could be an increased evidence of DNA damage among triathletes. However, similar effects were not observed with skeletal and cardiac muscle biomarkers.

Synthesis, DNA Binding, and Molecular Docking Studies of Dimethylaminobenzaldehyde-Based Bioactive Schiff Bases

A new series of p-dimethylaminobenzaldehyde derivatives were tested for therapeutic potential by exploring their properties through characterization. The derivatives were synthesized by 1 : 1 condensation reaction of p-dimethylaminobenzaldehyde and substituted amines. The synthesized compounds 1–8 were characterized by different characterization techniques including IR, mass, 1H NMR, and 13C NMR spectroscopy, elemental analysis, and mass spectrometry. Furthermore, binding of these Schiff bases to Ct-DNA was examined by absorption spectroscopy, fluorescence quenching, circular dichroic, viscosity measurement, molecular docking, and molecular dynamics simulation methods. Schiff bases were tested for antimicrobial activity against bacterial species Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Staphylococcus aureus by the disc diffusion method. The pharmacological treatment of Schiff bases showed that 1–8 have promising potential against tested bacterial strains. The molecular docking study of the target compounds was also carried out against B-DNA dodecamer d(CGCGAATTCGCG)2, and it has been found that 1–8 can bind to Ct-DNA via an intercalative mode. DPPH free radical and hydrogen peroxide scavenging assays were employed to assess the antioxidant potential of synthesized Schiff bases.

Leisure-time physical activity and DNA damage among Japanese workers

BACKGROUND

It remains unclear whether daily physical activity is associated with DNA damage. This cross-sectional study examined the association between leisure-time physical activity and urinary 8-hydroxydeoxyguanosine (8-OH-dG), a biomarker of oxidative DNA damage, or urinary 7-methylguanine (m7Gua), a biomarker of methylating DNA damage.

METHODS

Participants included 501 workers (294 men and 207 women), aged 20-65 years, from municipal offices in Japan. Urinary 8-OH-dG and m7Gua were measured using column-switching HPLC. Physical activity was evaluated using a self-reported questionnaire. The associations between leisure-time physical activity and urinary DNA damage markers were assessed by multiple linear regression analysis, with stratification by occupational physical activity.

RESULTS

After adjusting for covariates, leisure-time physical activity showed a suggestive inverse correlation with urinary 8-OH-dG levels (P for trend = 0.06), and a significant inverse association with urinary m7Gua levels (P for trend = 0.03). In analysis stratified by occupation, inverse correlations were observed in sedentary workers (walking < 30 min/day at work: P for trend = 0.06 and = 0.03 for urinary 8-OH-dG and m7Gua, respectively), but not in physically active workers (walking ≥ 30 min/day at work). In analysis for each intensity of leisure-time physical activity, light-intensity exercise was associated with lower levels of urinary 8-OH-dG (P for trend = 0.03), whereas moderate-to-high-intensity exercise was associated with lower levels of urinary m7Gua (P for trend = 0.02).

CONCLUSIONS

Our results suggest that high levels of leisure-time physical activity are associated with decreased levels of DNA damage in individuals with low physical activity at work.

Epigenetic changes due to physical activity

One of the epigenetic-modifying factors is regular and continuous physical activity. This article attempts to investigate the effects of physical activity and exercise on changes in histone proteins and gene expression, as well as the effect of these exercises on the prevention of certain cancers and the ejection of age-related illnesses and cellular oxidation interactions. All of this is due to epigenetic changes and gene expression. Most studies have reported the positive effects of regular exercises on the expression of histone proteins. DNA methylation and the prevention of certain diseases such as cancer and respiratory diseases, caused by antioxidative interactions that occur more often in the elderly, have been studied.

Antioxidants for preventing and reducing muscle soreness after exercise: a Cochrane systematic review

OBJECTIVE

To determine whether antioxidant supplements and antioxidant-enriched foods can prevent or reduce delayed-onset muscle soreness after exercise.

METHODS

We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register, the Cochrane Central Register of Controlled Trials, MEDLINE, Embase, SPORTDiscus, trial registers, reference lists of articles and conference proceedings up to February 2017.

RESULTS

In total, 50 studies were included in this review which included a total of 1089 participants (961 were male and 128 were female) with an age range of 16-55 years. All studies used an antioxidant dosage higher than the recommended daily amount. The majority of trials (47) had design features that carried a high risk of bias due to selective reporting and poorly described allocation concealment, potentially limiting the reliability of their findings. We rescaled to a 0-10 cm scale in order to quantify the actual difference between groups and we found that the 95% CIs for all five follow-up times were all well below the minimal important difference of 1.4 cm: up to 6 hours (MD -0.52, 95% CI -0.95 to -0.08); at 24 hours (MD -0.17, 95% CI -0.42 to 0.07); at 48 hours (mean difference (MD) -0.41, 95% CI -0.69 to -0.12); at 72 hours (MD -0.29, 95% CI -0.59 to 0.02); and at 96 hours (MD -0.03, 95% CI -0.43 to 0.37). Thus, the effect sizes suggesting less muscle soreness with antioxidant supplementation were very unlikely to equate to meaningful or important differences in practice.

CONCLUSIONS

There is moderate to low-quality evidence that high-dose antioxidant supplementation does not result in a clinically relevant reduction of muscle soreness after exercise of up to 6 hours or at 24, 48, 72 and 96 hours after exercise. There is no evidence available on subjective recovery and only limited evidence on the adverse effects of taking antioxidant supplements.

3-Acetyl-8-methoxy-2[H]-chromen-2-one derived Schiff bases as potent antiproliferative agents: Insight into the influence of 4(N)-substituents on the in vitro biological activity

A series of 3-acetyl-8-methoxycoumarin appended thiosemicarbazones (1-4) was prepared from the reaction of 3-acetyl-8-methoxycoumarin with 4(N)-substituted thiosemicarbazides in a view of ascertaining their biological properties with the change of N-terminal substitution in the thiosemicarbazide moiety. Comprehensive characterization was brought about by various spectral and analytical methods. The molecular structures of all the compounds were determined by single crystal X-ray diffraction analysis. Binding studies with Calf thymus DNA (CT-DNA) and proteins such as Bovine Serum Albumin (BSA) and Human Serum Albumin (HSA) indicated an intercalative mode of binding with DNA and static quenching mechanism with proteins. The compounds cleaved plasmid DNA (pBR322) and acted well as free radical scavengers. A good spectrum of antimicrobial activity was observed against four bacterial and five fungal pathogens. The compounds exhibited profound antiproliferative activity on MCF-7 (human breast cancer) and A549 (human lung carcinoma) cell lines. Assay on human normal keratinocyte cell line HaCaT showed that the compounds were non-toxic to normal cells.

Exogenous Plant-Based Nutraceutical Supplementation and Peripheral Cell Mononuclear DNA Damage Following High Intensity Exercise

Plant-based nutraceuticals are categorised as nutritional supplements which contain a high concentration of antioxidants with the intention of minimising the deleterious effect of an oxidative insult. The primary aim of this novel study was to determine the effect of exogenous barley-wheat grass juice (BWJ) on indices of exercise-induced oxidative stress. Ten (n = 10) apparently healthy, recreationally trained (V̇O_2max 55.9 ± 6 mL&middot;kg^&minus;1&middot;min^&minus;1), males (age 22 ± 2 years, height 181 ± 6 cm, weight 87 ± 8 kg, body mass index (BMI) 27 ± 1) volunteered to participant in the study. In a randomised, double-blinded, placebo-controlled crossover design, participants consumed either a placebo, a low dose (70 mL per day) of BWJ, or a high dose (140 mL per day) of BWJ for 7-days. Experimental exercise consisted of a standard maximal oxygen uptake test until volitional fatigue. DNA damage, as assessed by the single cell gel electrophoresis comet assay, increased following high intensity exercise across all groups (time &times; group; p < 0.05, Effect Size (ES) = 0.7), although there was no selective difference for intervention (p > 0.05). There was a main effect for time in lipid hydroperoxide concentration (pooled-group data, pre- vs. post-exercise, p < 0.05, ES = 0.2) demonstrating that exercise increased lipid peroxidation. Superoxide dismutase activity (SOD) increased by 44.7% following BWJ supplementation (pooled group data, pre- vs. post). The ascorbyl free radical (p < 0.05, ES = 0.26), &alpha;-tocopherol (p = 0.007, ES = 0.2), and xanthophyll (p = 0.000, ES = 0.5), increased between the pre- and post-exercise time points indicating a main effect of time. This study illustrates that a 7-day supplementation period of a novel plant-derived nutraceutical product is insufficient at attenuating exercise-induced oxidative damage. It is possible that with a larger sample size, and longer supplementation period, this novel plant-based nutraceutical could potentially offer effective prophylaxis against exercise-induced oxidative stress; as such, this justifies the need for further research.

Immune cell response to strenuous resistive breathing: comparison with whole body exercise and the effects of antioxidants

Background/hypothesis

Whole body exercise (WBE) changes lymphocyte subset percentages in peripheral blood. Resistive breathing, a hallmark of diseases of airway obstruction, is a form of exercise for the inspiratory muscles. Strenuous muscle contractions induce oxidative stress that may mediate immune alterations following exercise. We hypothesized that inspiratory resistive breathing (IRB) alters peripheral blood lymphocyte subsets and that oxidative stress mediates lymphocyte subpopulation alterations following both WBE and IRB.

Patients and methods

Six healthy nonathletes performed two WBE and two IRB sessions for 45 minutes at 70% of VO₂ maximum and 70% of maximum inspiratory pressure (Pi_max), respectively, before and after the administration of antioxidants (vitamins E, A, and C for 75 days, allopurinol for 30 days, and N-acetylcysteine for 3 days). Blood was drawn at baseline, at the end of each session, and 2 hours into recovery. Lymphocyte subsets were determined by flow cytometry.

Results

Before antioxidant supplementation at both WBE end and IRB end, the natural killer cell percentage increased, the T helper cell (CD3+ CD4+) percentage was reduced, and the CD4/CD8 ratio was depressed, a response which was abolished by antioxidants only after IRB. Furthermore, at IRB end, antioxidants promoted CD8+ CD38+ and blunted cytotoxic T-cell percentage increase. CD8+ CD45RA+ cell percentage changes were blunted after antioxidant supplementation in both WBE and IRB.

Conclusion

We conclude that IRB produces (as WBE) changes in peripheral blood lymphocyte subsets and that oxidative stress is a major stimulus predominantly for IRB-induced lymphocyte subset alterations.

Cyclometallated ruthenium(ii) complexes with 3-acetyl-2[H]-chromene-2-one derived CNS chelating ligand systems: synthesis, X-ray characterization and biological evaluation

The presented work focuses on the synthesis and biological evaluation of 3-acetylcoumarin Schiff bases and their cyclometallated ruthenium(ii) metallates.

Antioxidants for preventing and reducing muscle soreness after exercise

BACKGROUND

Muscle soreness typically occurs after intense exercise, unaccustomed exercise or actions that involve eccentric contractions where the muscle lengthens while under tension. It peaks between 24 and 72 hours after the initial bout of exercise. Many people take antioxidant supplements or antioxidant-enriched foods before and after exercise in the belief that these will prevent or reduce muscle soreness after exercise.

OBJECTIVES

To assess the effects (benefits and harms) of antioxidant supplements and antioxidant-enriched foods for preventing and reducing the severity and duration of delayed onset muscle soreness following exercise.

SEARCH METHODS

We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register, the Cochrane Central Register of Controlled Trials, MEDLINE, Embase, SPORTDiscus, trial registers, reference lists of articles and conference proceedings up to February 2017.

SELECTION CRITERIA

We included randomised and quasi-randomised controlled trials investigating the effects of all forms of antioxidant supplementation including specific antioxidant supplements (e.g. tablets, powders, concentrates) and antioxidant-enriched foods or diets on preventing or reducing delayed onset muscle soreness (DOMS). We excluded studies where antioxidant supplementation was combined with another supplement.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened search results, assessed risk of bias and extracted data from included trials using a pre-piloted form. Where appropriate, we pooled results of comparable trials, generally using the random-effects model. The outcomes selected for presentation in the 'Summary of findings' table were muscle soreness, collected at times up to 6 hours, 24, 48, 72 and 96 hours post-exercise, subjective recovery and adverse effects. We assessed the quality of the evidence using GRADE.

MAIN RESULTS

Fifty randomised, placebo-controlled trials were included, 12 of which used a cross-over design. Of the 1089 participants, 961 (88.2%) were male and 128 (11.8%) were female. The age range for participants was between 16 and 55 years and training status varied from sedentary to moderately trained. The trials were heterogeneous, including the timing (pre-exercise or post-exercise), frequency, dose, duration and type of antioxidant supplementation, and the type of preceding exercise. All studies used an antioxidant dosage higher than the recommended daily amount. The majority of trials (47) had design features that carried a high risk of bias due to selective reporting and poorly described allocation concealment, potentially limiting the reliability of their findings.We tested only one comparison: antioxidant supplements versus control (placebo). No studies compared high-dose versus low-dose, where the low-dose supplementation was within normal or recommended levels for the antioxidant involved.Pooled results for muscle soreness indicated a small difference in favour of antioxidant supplementation after DOMS-inducing exercise at all main follow-ups: up to 6 hours (standardised mean difference (SMD) -0.30, 95% confidence interval (CI) -0.56 to -0.04; 525 participants, 21 studies; low-quality evidence); at 24 hours (SMD -0.13, 95% CI -0.27 to 0.00; 936 participants, 41 studies; moderate-quality evidence); at 48 hours (SMD -0.24, 95% CI -0.42 to -0.07; 1047 participants, 45 studies; low-quality evidence); at 72 hours (SMD -0.19, 95% CI -0.38 to -0.00; 657 participants, 28 studies; moderate-quality evidence), and little difference at 96 hours (SMD -0.05, 95% CI -0.29 to 0.19; 436 participants, 17 studies; low-quality evidence). When we rescaled to a 0 to 10 cm scale in order to quantify the actual difference between groups, we found that the 95% CIs for all five follow-up times were all well below the minimal important difference of 1.4 cm: up to 6 hours (MD -0.52, 95% CI -0.95 to -0.08); at 24 hours (MD -0.17, 95% CI -0.42 to 0.07); at 48 hours (MD -0.41, 95% CI -0.69 to -0.12); at 72 hours (MD -0.29, 95% CI -0.59 to 0.02); and at 96 hours (MD -0.03, 95% CI -0.43 to 0.37). Thus, the effect sizes suggesting less muscle soreness with antioxidant supplementation were very unlikely to equate to meaningful or important differences in practice. Neither of our subgroup analyses to examine for differences in effect according to type of DOMS-inducing exercise (mechanical versus whole body aerobic) or according to funding source confirmed subgroup differences. Sensitivity analyses excluding cross-over trials showed that their inclusion had no important impact on results.None of the 50 included trials measured subjective recovery (return to previous activities without signs or symptoms).There is very little evidence regarding the potential adverse effects of taking antioxidant supplements as this outcome was reported in only nine trials (216 participants). From the studies that did report adverse effects, two of the nine trials found adverse effects. All six participants in the antioxidant group of one trial had diarrhoea and four of these also had mild indigestion; these are well-known side effects of the particular antioxidant used in this trial. One of 26 participants in a second trial had mild gastrointestinal distress.

AUTHORS' CONCLUSIONS

There is moderate to low-quality evidence that high dose antioxidant supplementation does not result in a clinically relevant reduction of muscle soreness after exercise at up to 6 hours or at 24, 48, 72 and 96 hours after exercise. There is no evidence available on subjective recovery and only limited evidence on the adverse effects of taking antioxidant supplements. The findings of, and messages from, this review provide an opportunity for researchers and other stakeholders to come together and consider what are the priorities, and underlying justifications, for future research in this area.

DNA damage in Wistar Kyoto rats exercised during pregnancy

Purpose:

To evaluate DNA damage levels in pregnant rats undergoing a treadmill exercise program.

Methods:

Wistar Kyoto rats were allocated into two groups (n= 5 animals/group): non-exercise and exercise. The pregnant rats were underwent an exercise protocol on a treadmill throughout pregnancy. Exercise intensity was set at 50% of maximal capacity during maximal exercise testing performed before mating. Body weight, blood pressure and glucose levels, and triglyceride concentration were measured during pregnancy. At day 10 post-natal, the animals were euthanized and maternal blood samples were collected for DNA damage.

Results:

Blood pressure and glucose levels and biochemical measurements showed no significant differences. Increased DNA damage levels were found in exercise group compared to those of non-exercise group (p<0.05).

Conclusion:

The exercise intensity protocol used in the study might have been exhaustive leading to maternal increased DNA damage levels, demonstrating the relevance of an adequate protocol of physical exercise.

Use of anabolic androgenic steroids produces greater oxidative stress responses to resistance exercise in strength-trained men

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Single session of high-intensity RE on trained bodybuilder men had effect on DNA damage and oxidative stress.

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The AAS users showed greater response than NAAS users. At pre-RE, the levels of oxidant were greater for the AAS group.

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The study has reported a range of negative redox status consequence of AAS use in conjunction with resistance training.

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The alteration of oxidative stress status with AAS use likely increase the injury risks in some organs in athletes.

The aim of this study was to determine the effect of anabolic androgenic steroids (AAS) use on oxidative stress responses to a single session of resistance exercise in strength-trained men. Twenty-three strength trained men, with 11 self-reporting regular AAS use and 12 self-reporting never taking AAS (NAAS) volunteered to participate in this study. Blood draws were obtained pre and post resistance exercise in order to evaluate changes in oxidative stress biomarkers levels (i.e., 8-hydroxy-2-deoxyguanosine [8-OHdG], malondialdehyde [MDA], and nitric oxide [NO]), antioxidant defense systems (i.e., glutathione peroxidase [GPx] and catalase [CAT]), and glucose (GLU) levels. The AAS users had higher level of 8-OHdG (77.3 ± 17 vs. 57.7 ± 18.2 ng/mg), MDA (85.6 ± 17.8 vs. 52.3 ± 15.1 ng/mL), and GPx (9.1 ± 2.3 vs. 7.1 ± 1.3 mu/mL) compared to NAAS at pre exercise (p < 0.05). Both the experimental groups showed increases in 8-OHdG (p = 0.001), MDA (p = 0.001), GPx (p = 0.001), NO (p = 0.04), CAT (p = 0.02) and GLU (p = 0.001) concentrations after resistance exercise, and the AAS group indicated significant differences in 8-OHdG (p = 0.02) and MDA (p = 0.05) concentrations compared with NAAS users at post exercise. In conclusion, use of AAS is associated with alterations in immune function resulting in oxidative stress, and cell damage; however, high-intensity resistance exercise could increase greater oxidative stress biomarkers in strength-trained men.

Variations in Oxidative Stress Levels in 3 Days Follow-up in Ultramarathon Mountain Race Athletes

Spanidis, Y, Stagos, D, Orfanou, M, Goutzourelas, N, Bar-or, D, Spandidos, D, and Kouretas, D. Variations in oxidative stress levels in 3 days follow-up in ultramarathon mountain race athletes. J Strength Cond Res 31(3): 582-594, 2017-The aim of the present study was the monitoring of the redox status of runners participating in a mountain ultramarathon race of 103 km. Blood samples from 12 runners were collected prerace and 24, 48, and 72 hours postrace. The samples were analyzed by using conventional oxidative stress markers, such as protein carbonyls (CARB), thiobarbituric acid reactive substances (TBARS), total antioxidant capacity (TAC) in plasma, as well as glutathione (GSH) levels and catalase (CAT) activity in erythrocytes. In addition, 2 novel markers, the static oxidation-reduction potential marker (sORP) and the capacity oxidation-reduction potential (cORP), were measured in plasma. The results showed significant increase in sORP levels and significant decrease in cORP and GSH levels postrace compared with prerace. The other markers did not exhibit significant changes postrace compared with prerace. Furthermore, an interindividual analysis showed that in all athletes but one sORP was increased, whereas cORP was decreased. Moreover, GSH levels were decreased in all athletes at least at 2 time points postrace compared with prerace. The other markers exhibited great variations between different athletes. In conclusion, ORP and GSH markers suggested that oxidative stress has existed even 3 days post ultramarathon race. The practical applications from these results would be that the most effective markers for short-term monitoring of ultramarathon mountain race-induced oxidative stress were sORP, cORP, and GSH. Also, administration of supplements enhancing especially GSH is recommended during ultramarathon mountain races to prevent manifestation of pathological conditions.

Dietary thiols in exercise: oxidative stress defence, exercise performance, and adaptation

Endurance athletes are susceptible to cellular damage initiated by excessive levels of aerobic exercise-produced reactive oxygen species (ROS). Whilst ROS can contribute to the onset of fatigue, there is increasing evidence that they play a crucial role in exercise adaptations. The use of antioxidant supplements such as vitamin C and E in athletes is common; however, their ability to enhance performance and facilitate recovery is controversial, with many studies suggesting a blunting of training adaptations with supplementation. The up-regulation of endogenous antioxidant systems brought about by exercise training allows for greater tolerance to subsequent ROS, thus, athletes may benefit from increasing these systems through dietary thiol donors. Recent work has shown supplementation with a cysteine donor (N-acetylcysteine; NAC) improves antioxidant capacity by augmenting glutathione levels and reducing markers of oxidative stress, as well as ergogenic potential through association with delayed fatigue in numerous experimental models. However, the use of this, and other thiol donors may have adverse physiological effects. A recent discovery for the use of a thiol donor food source, keratin, to potentially enhance endogenous antioxidants may have important implications for endurance athletes hoping to enhance performance and recovery without blunting training adaptations.

Physical Exercise and DNA Injury: Good or Evil?

Regular, low-intensity physical activity is currently advocated for lowering the risk of developing many acute and especially chronic diseases. However, several lines of evidence attest that strenuous exercise may enhance inflammation and trigger the generation of free radical-mediated damage, thus overwhelming the undisputable benefits of regular, medium-intensity physical activity. Since reactive oxygen species are actively generated during high-intensity exercise, and these reactive compounds are known to impact DNA stability, we review here the current evidence about strenuous exercise and DNA injury. Despite the outcome of the various studies cannot be pooled due to considerable variation in design, sample population, outcome, and analytical techniques used to assess DNA damage, it seems reasonable to conclude that medium- to high-volume exercise triggers a certain amount of DNA injury, which appears to be transitory and directly proportional to exercise intensity. This damage, reasonably attributable to direct effect of free radicals on nucleic acids, is efficiently repaired in vivo within 24-72h. Therefore, physical exercise should not bear long-term consequences for athlete's health provided that an appropriate time of recovery between volumes of high-intensity exercise is set. Regular exertion, with a step-by-step increase of exercise load, also seems to be the most safe approach for eluding DNA instability.

The effect of incorporating carboxylic acid functionalities into 2,2′-bipyridine on the biological activity of the complexes formed: synthesis, structure, DNA/protein interaction, antioxidant activity and cytotoxicity

Incorporation of carboxylic acid group in the bipyridine moiety has resulted in showing differences in DNA/protein binding affinity, efficiency in antioxidant activity and cytotoxicity.

A randomized controlled trial examining the effects of 16 weeks of moderate-to-intensive cycling and honey supplementation on lymphocyte oxidative DNA damage and cytokine changes in male road cyclists

The aim of this study was to investigate whether honey supplementation (70g, ninety minutes before each training session) attenuates changes in lymphocyte counts, DNA damage, cytokines, antioxidative and peroxidative biomarkers following moderate-to-intensive exercise training in male road cyclists. Healthy nonprofessional cyclists (n=24, aged 17-26years) were randomly assigned to exercise+supplement (EX+S, n=12) and exercise (EX, n=12) groups for an experimental period of 16weeks. Moderate-to-intensive exercise training increased lymphocytes DNA damage, cytokines and peroxidative biomarkers as well as decreased antioxidative biomarkers in the EX group. These changes were significantly attenuated in the EX+S group. Furthermore, for both groups the observed changes in peroxidative and antioxidative biomarkers could be correlated positively and negatively, respectively, with lymphocyte DNA damage and cytokines. Findings suggest that honey attenuates oxidative stress and lymphocyte DNA damage after exercise, activities that are most likely attributable to its high antioxidant capacity.

Evidence of a Redox-Dependent Regulation of Immune Responses to Exercise-Induced Inflammation

We used thiol-based antioxidant supplementation (n-acetylcysteine, NAC) to determine whether immune mobilisation following skeletal muscle microtrauma induced by exercise is redox-sensitive in healthy humans. According to a two-trial, double-blind, crossover, repeated measures design, 10 young men received either placebo or NAC (20 mg/kg/day) immediately after a muscle-damaging exercise protocol (300 eccentric contractions) and for eight consecutive days. Blood sampling and performance assessments were performed before exercise, after exercise, and daily throughout recovery. NAC reduced the decline of reduced glutathione in erythrocytes and the increase of plasma protein carbonyls, serum TAC and erythrocyte oxidized glutathione, and TBARS and catalase activity during recovery thereby altering postexercise redox status. The rise of muscle damage and inflammatory markers (muscle strength, creatine kinase activity, CRP, proinflammatory cytokines, and adhesion molecules) was less pronounced in NAC during the first phase of recovery. The rise of leukocyte and neutrophil count was decreased by NAC after exercise. Results on immune cell subpopulations obtained by flow cytometry indicated that NAC ingestion reduced the exercise-induced rise of total macrophages, HLA⁺ macrophages, and 11B⁺ macrophages and abolished the exercise-induced upregulation of B lymphocytes. Natural killer cells declined only in PLA immediately after exercise. These results indicate that thiol-based antioxidant supplementation blunts immune cell mobilisation in response to exercise-induced inflammation suggesting that leukocyte mobilization may be under redox-dependent regulation.

Intensity-specific effect of physical activity on urinary levels of 8-hydroxydeoxyguanosine in middle-aged Japanese

Physical activity (PA) is recommended to both promote and maintain health and prevent cancer by improving the body's DNA repair system, which is considered a mechanism of cancer prevention. However, associations between PA and urinary levels of 8-hydroxydeoxyguanosine (8-OH-dG), which reflects DNA damage, are unclear. This cross-sectional study included 2370 men and 4052 women aged 45-74 years enrolled between 2010 and 2012. Habitual PA was assessed by single-axis accelerometer and urinary 8-OH-dG levels by automated HPLC. Multiple linear regression analysis was used to examine the relationship between log-transformed urinary 8-OH-dG and total PA (TPA) and PA of moderate/vigorous intensity (MVPA; ≥3 metabolic equivalents), with adjustment for age, body mass index, energy intake, alcohol consumption, smoking status, daily coffee drinking, menopause status (in women), and TPA (for MVPA). On multivariate adjustment, urinary 8-OH-dG levels were inversely correlated with TPA (β = -0.020, P < 0.01) in women, and this correlation was not changed by PA intensity. Conversely, urinary 8-OH-dG levels were inversely correlated with MVPA (β = -0.022, P < 0.05) in men, although the correlation with TPA was non-significant. This inverse correlation was clearer in current smokers than in never or former smokers, although the interaction between smoking status and MVPA on urinary 8-OH-dG levels was non-significant. In conclusion, greater TPA in women and greater MVPA in men were correlated with reduction in urinary 8-OH-dG, suggesting sex-specific effects of MVPA and TPA on protection from oxidative DNA damage. Increasing PA may mediate reduction in oxidative stress.

Distinctive adaptive response to repeated exposure to hydrogen peroxide associated with upregulation of DNA repair genes and cell cycle arrest

Many environmental and physiological stresses are chronic. Thus, cells are constantly exposed to diverse types of genotoxic insults that challenge genome stability, including those that induce oxidative DNA damage. However, most in vitro studies that model cellular response to oxidative stressors employ short exposures and/or acute stress models. In this study, we tested the hypothesis that chronic and repeated exposure to a micromolar concentration of hydrogen peroxide (H₂O₂) could activate DNA damage responses, resulting in cellular adaptations. For this purpose, we developed an in vitro model in which we incubated mouse myoblast cells with a steady concentration of ~50 μM H₂O₂ for one hour daily for seven days, followed by a final challenge of a 10 or 20X higher dose of H₂O₂ (0.5 or 1 mM). We report that intermittent long-term exposure to this oxidative stimulus nearly eliminated cell toxicity and significantly decreased genotoxicity (in particular, a >5-fold decreased in double-strand breaks) resulting from subsequent acute exposure to oxidative stress. This protection was associated with cell cycle arrest in G2/M and induction of expression of nine DNA repair genes. Together, this evidence supports an adaptive response to chronic, low-level oxidative stress that results in genomic protection and up-regulated maintenance of cellular homeostasis.

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Repetitive stimulus with subtoxic H₂O₂ resulted in cellular adaptive response.

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Cells responded by abridged cytotoxicity and reduced intracellular ROS.

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Adaptive response mitigated the genotoxicity of acute oxidative insults.

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Adaption induced overexpression of selected genes of the BER, NER, MMR pathways.

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Chronic and repetitive H₂O₂ resulted in cell cycle checkpoint arrest.

Exercise and Oxidative Damage in Nucleoid DNA Quantified Using Single Cell Gel Electrophoresis: Present and Future Application

High intensity exercise can enhance the production of reactive oxygen and nitrogen free radical species, which may cause a number of perturbations to cellular integrity, including deoxyribonucleic acid (DNA) modification. In the absence of adequate DNA repair, it is theoretically possible that several biological disorders may ensue, in addition to premature aging. This striking hypothesis and supposition can only be realized in the presence of sound methodology for the quantification of DNA damage and repair. The alkaline single-cell gel electrophoresis or "comet assay" is a simple and reliable method for measuring the components of DNA stability in eukaryotic cells. The assay is commonly used in research associated with genotoxicology and in human bio-monitoring studies concerned with gene-environment interactions; but is currently less appreciated and under-utilized in the domain of exercise science. No exercise related study for example, has incorporated the comet assay combined with fluorescent in situ hybridization methodology to detect and investigate whole genome, telomeric DNA, or gene region-specific DNA damage and repair in cells. Our laboratory and others have used the comet assay in conjunction with lesion-specific endonucleases to measure DNA strand breaks and oxidized bases to confirm that high intensity exercise can damage and destabilize DNA. Thus, the primary function of this review is to highlight recent advances and innovation with the comet assay, in order to enhance our future understanding of the complex interrelationship between exercise and DNA modification in eukaryotic cells. A brief synopsis of the current literature addressing DNA stability as a function of continuous aerobic exercise is also included.

No effect of caloric restriction or exercise on radiation repair capacity

INTRODUCTION

Maintenance of normal weight and higher levels of physical activity are associated with a reduced risk of several types of cancer. Because genomic instability is regarded as a hallmark of cancer development, one proposed mechanism is improvement of DNA repair function. We investigated links between dietary weight loss, exercise, and strand break rejoining in an ancillary study to a randomized-controlled trial.

METHODS

Overweight/obese postmenopausal women (n = 439) were randomized to the following: a) reduced calorie weight loss diet ("diet," n = 118), b) moderate- to vigorous-intensity aerobic exercise ("exercise," n = 117), c) a combination ("diet + exercise," n = 117), or d) control (n = 87). The reduced calorie diet had a 10% weight loss goal. The exercise intervention consisted of 45 min of moderate to vigorous aerobic activity 5 d·wk for 12 months. DNA repair capacity was measured in a subset of 226 women at baseline and 12 months from cryopreserved peripheral mononuclear cells using the comet assay. Anthropometric and body composition measures were performed at baseline and 12 months.

RESULTS

DNA repair capacity did not change significantly with any of the 12-month interventions compared with control; there were also no significant changes when stratified by changes in body composition or aerobic fitness (V˙O2max). At baseline, DNA repair capacity was positively associated with weight, body mass index, and fat mass (r = 0.20, P = 0.003; r = 0.19, P = 0.004; r = 0.13, P = 0.04, respectively) and inversely with lean body mass (r = -0.14, P = 0.04).

CONCLUSION

In conclusion, DNA repair capacity in cryopreserved PBMCs (Comet Assay) did not change with dietary weight loss or exercise interventions in postmenopausal women within a period of 12 months. Other assays that capture different facets of DNA repair function may be needed.

Magnesium Supplementation Diminishes Peripheral Blood Lymphocyte DNA Oxidative Damage in Athletes and Sedentary Young Man

Sedentary lifestyle is highly associated with increased risk of cardiovascular disease, obesity, and type 2 diabetes. It is known that regular physical activity has positive effects on health; however several studies have shown that acute and strenuous exercise can induce oxidative stress and lead to DNA damage. As magnesium is essential in maintaining DNA integrity, the aim of this study was to determine whether four-week-long magnesium supplementation in students with sedentary lifestyle and rugby players could prevent or diminish impairment of DNA. By using the comet assay, our study demonstrated that the number of peripheral blood lymphocytes (PBL) with basal endogenous DNA damage is significantly higher in rugby players compared to students with sedentary lifestyle. On the other hand, magnesium supplementation significantly decreased the number of cells with high DNA damage, in the presence of exogenous H₂O₂, in PBL from both students and rugby players, and markedly reduced the number of cells with medium DNA damage in rugby players compared to corresponding control nonsupplemented group. Accordingly, the results of our study suggest that four-week-long magnesium supplementation has marked effects in protecting the DNA from oxidative damage in both rugby players and in young men with sedentary lifestyle. Clinical trial is registered at ANZCTR Trial Id: ACTRN12615001237572.

Impact of different running distances on muscle and lymphocyte DNA damage in amateur marathon runners

[Purpose] The aim of this study was to investigate the impact of different marathon running distances (10 km, 21 km, and 42.195 km) on muscle and lymphocyte DNA damage in amateur marathon runners. [Subjects and Methods] Thirty male amateur runners were randomly assigned to 10 km, 21 km, and 42 km groups, with 10 subjects in each group. Blood samples were collected before and after the races and on the 3rd day of recovery to examine levels of muscle damage (creatine kinase and lactate dehydrogenase) and lymphocyte DNA damage (DNA in the tail, tail length, and tail moment). [Results] Serum creatine kinase, serum lactate dehydrogenase, and tail moment were significantly higher after the races compared with before the races in all groups. In addition, the 42 km group showed significantly higher levels of creatine kinase, lactate dehydrogenase, and tail moment than the 10 km and 21 km groups after the races. [Conclusion] Strenuous endurance exercise can cause muscle and lymphocyte DNA damage, and the extent of such damage can increase as running distance increases.

Effect of lit-moxa stimulation of Guanyuan (CV 4) acupoint on levels of lactic acid and superoxide dismutase in skeletal muscle of rats

OBJECTIVE

To observe the effect of lit-moxa stimu- lating acupoint Guanyuan (CV 4) on lactic acid and super-oxide dismutase (SOD) in skeletal muscle after exercise exhaustion.

METHODS

Twenty-eight adult male Sprague-Dawley rats were randomly divided into normal control group, exhausted control group, exercise group and moxibustion group using exercise training and mild heating with lit-moxa stick as treatment methods. The exhausted control group, moxibustion group and exercise group received an exhaustive swimming after 20 days of intervention. Swimming exhausted times were recorded. Lactic acid and SOD concentration in soleus muscle were detected and compared between every two groups.

RESULTS

The swimming exhausted times of the moxibustion group and the exercise group were significantly increased compare to the exhausted control group (P < 0.05). The lactic acid of the exhausted control group was significantly increased comparing with the normal control group (P < 0.05), and the lactic acid of the moxibustion group and the exercise group were significantly lower than that of the exhausted control group (P < 0.05). The SOD level of the exhausted control group was significantly decreased comparing with the normal control group (P < 0.05), and the SOD level of the moxibustion group and the exercise group were significantly higher than that of the exhausted control group (both, P < 0.05). There was no statistical difference between the moxibustion group and the exercise group.

CONCLUSION

With lit moxa stick, heat stimulating acupoint of Guanyuan (CV 4) decreased the levels of lactic acid and SOD in rat's skeletal muscle.