Vitamin E supplementation inhibits muscle damage and inflammation after moderate exercise in hypoxia

Potential Vitamin E Signaling Mediators in Skeletal Muscle

Vitamin E (Vit E) deficiency studies underline the relevance of this vitamin in skeletal muscle (SkM) homeostasis. The knowledge of the effectors and modulators of Vit E action in SkM cells is limited, especially in aging and chronic diseases characterized by a decline in musculoskeletal health. Vit E comprises eight fat-soluble compounds grouped into tocopherols and tocotrienols, which share the basic chemical structure but show different biological properties and potentials to prevent diseases. Vit E has antioxidant and non-antioxidant activities and both favorable and adverse effects depending on the specific conditions and tissues. In this review, we focus on the actual knowledge of Vit E forms in SkM functions and new potential signaling effectors (i.e., bioactive sphingolipids and myokines). The possible advantages of Vit E supplementation in counteracting SkM dysfunctions in sarcopenia and under microgravity will also be discussed.

Effects of hyperbaric oxygen therapy on recovery after a football match in young players: a double-blind randomized controlled trial

Introduction

Football is a physically demanding sport that requires effective recovery strategies to maintain performance level and prevent injuries. This study investigated if a single 1-h hyperbaric oxygen therapy (HBOT) session affects recovery and performance after a football match in elite youth players.

Methods

Twenty elite youth football players (age 17.3 ± 0.5 years) were randomly assigned to a HBOT group or a control group (CON). They played a 90-min football game and underwent either a 60-min HBOT or placebo intervention. Before (T1), at the end of the match (T2), 1 h after HBOT or CON session (T3), and 12 h after HBOT session (T4), subjects underwent biochemical (serum samples (myoglobin (MB), creatine kinase (CK), lactate dehydrogenase (LDH), alanine aminotransferase (ALT), and aspartate aminotransferase (AST)) and performance measurements (linear speed at 5 m, 10 m and 20 m, squat jump (SJ), countermovement jump (CMJ) and countermovement jump with arm swing (CMJa)). The Hooper Index (HI) was collected and heart rate was measured during the game.

Results

The football match induced significant increases in all biochemical markers, but no significant differences were found between the HBOT and control group in biochemical or performance parameters at any time point. However, there was a significant interaction effect between time and group for HI (p = 0.012, η2 = 0.124), with the HBOT group showing significantly lower HI values (8.6 ± 2.41) than the control group (11.0 ± 3.23) at 1 h post-HBOT.

Discussion

A single 1-h session of HBOT did not significantly affect recovery or performance parameters in elite youth football players, though it did show a moderate positive affect on the HI at 1 h post-HBOT. Further studies should explore the impact of either longer or sequential HBOT sessions on recovery.

Immune consequences of exercise in hypoxia: A narrative review

Immune outcomes are key mediators of many health benefits of exercise and are determined by exercise type, dose (frequency/duration, intensity), and individual characteristics. Similarly, reduced availability of ambient oxygen (hypoxia) modulates immune functions depending on the hypoxic dose and the individual capacity to respond to hypoxia. How combined exercise and hypoxia (e.g., high-altitude training) sculpts immune responses is not well understood, although such combinations are becoming increasingly popular. Therefore, in this paper, we summarize the impact on immune responses of exercise and of hypoxia, both independently and together, with a focus on specialized cells in the innate and adaptive immune system. We review the regulation of the immune system by tissue oxygen levels and the overlapping and distinct immune responses related to exercise and hypoxia, then we discuss how they may be modulated by nutritional strategies. Mitochondrial, antioxidant, and anti-inflammatory mechanisms underlie many of the adaptations that can lead to improved cellular metabolism, resilience, and overall immune functions by regulating the survival, differentiation, activation, and migration of immune cells. This review shows that exercise and hypoxia can impair or complement/synergize with each other while regulating immune system functions. Appropriate acclimatization, training, and nutritional strategies can be used to avoid risks and tap into the synergistic potentials of the poorly studied immune consequences of exercising in a hypoxic state.

Impact of Exercise in Hypoxia on Inflammatory Cytokines in Adults: A Systematic Review and Meta-analysis

BACKGROUND

Both acute exercise and environmental hypoxia may elevate inflammatory cytokines, but the inflammatory response in the hypoxic exercise is remaining unknown.

OBJECTIVE

We performed this systematic review and meta-analysis to examine the effect of exercise in hypoxia on inflammatory cytokines, including IL-6, TNF-α and IL-10.

METHODS

PubMed, Scopus and Web of Science were searched to identify the original articles that compared the effect of exercise in hypoxia with normoxia on IL-6, TNF-α and IL-10 changes, published up to March 2023. Standardized mean differences and 95% confidence intervals (CIs) were calculated using a random effect model to (1) determine the effect of exercise in hypoxia, (2) determine the effect of exercise in normoxia and (3) compare the effect of exercise in hypoxia with normoxia on IL-6, TNF-α and IL-10 responses.

RESULTS

Twenty-three studies involving 243 healthy, trained and athlete subjects with a mean age range from 19.8 to 41.0 years were included in our meta-analysis. On comparing exercise in hypoxia with normoxia, no differences were found in the response of IL-6 [0.17 (95% CI - 0.08 to 0.43), p = 0.17] and TNF-α [0.17 (95% CI - 0.10 to 0.46), p = 0.21] between the conditions. Exercise in hypoxia significantly increased IL-10 concentration [0.60 (95% CI 0.17 to 1.03), p = 0.006] compared with normoxia. In addition, exercise during both hypoxia and normoxia increased IL-6 and IL-10, whereas TNF-α was increased only in hypoxic exercise condition.

CONCLUSION

Overall, exercise in both hypoxia and normoxia increased inflammatory cytokines; however, hypoxic exercise may lead to a greater inflammatory response in adults.

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.

Mechanisms for Combined Hypoxic Conditioning and Divergent Exercise Modes to Regulate Inflammation, Body Composition, Appetite, and Blood Glucose Homeostasis in Overweight and Obese Adults: A Narrative Review

Obesity is a major global health issue and a primary risk factor for metabolic-related disorders. While physical inactivity is one of the main contributors to obesity, it is a modifiable risk factor with exercise training as an established non-pharmacological treatment to prevent the onset of metabolic-related disorders, including obesity. Exposure to hypoxia via normobaric hypoxia (simulated altitude via reduced inspired oxygen fraction), termed hypoxic conditioning, in combination with exercise has been increasingly shown in the last decade to enhance blood glucose regulation and decrease the body mass index, providing a feasible strategy to treat obesity. However, there is no current consensus in the literature regarding the optimal combination of exercise variables such as the mode, duration, and intensity of exercise, as well as the level of hypoxia to maximize fat loss and overall body compositional changes with hypoxic conditioning. In this narrative review, we discuss the effects of such diverse exercise and hypoxic variables on the systematic and myocellular mechanisms, along with physiological responses, implicated in the development of obesity. These include markers of appetite regulation and inflammation, body conformational changes, and blood glucose regulation. As such, we consolidate findings from human studies to provide greater clarity for implementing hypoxic conditioning with exercise as a safe, practical, and effective treatment strategy for obesity.

Nutritional Compounds to Improve Post-Exercise Recovery

The metabolic and mechanical stresses associated with muscle-fatiguing exercise result in perturbations to bodily tissues that lead to exercise-induced muscle damage (EIMD), a state of fatigue involving oxidative stress and inflammation that is accompanied by muscle weakness, pain and a reduced ability to perform subsequent training sessions or competitions. This review collates evidence from previous research on a wide range of nutritional compounds that have the potential to speed up post-exercise recovery. We show that of the numerous compounds investigated thus far, only two-tart cherry and omega-3 fatty acids-are supported by substantial research evidence. Further studies are required to clarify the potential effects of other compounds presented here, many of which have been used since ancient times to treat conditions associated with inflammation and disease.

Effects of Acute Vitamin C plus Vitamin E Supplementation on Exercise-Induced Muscle Damage in Runners: A Double-Blind Randomized Controlled Trial

Considering the existing controversy over the possible role of acute antioxidant vitamins in reducing exercise-induced muscle damage (EIMD), this doubled-blind, randomized and controlled trial aimed to determine whether supplementation with vitamins C and E could mitigate the EIMD in endurance-trained runners (n = 18). The exercise protocol involved a warm-up followed by 6 to 8 bouts of 1 km running at 75% maximum heart rate (HRmax). Two hours before the exercise protocol, participants took the supplementation with vitamins or placebo, and immediately afterwards, blood lactate, rate of perceived exertion and performance were assessed. At 24 h post-exercise, CK, delayed onset muscle soreness and performance were determined (countermovement jump, squat jump and stiffness test). The elastic index and vertical stiffness were calculated using a stiffness test. Immediately after the exercise protocol, all participants showed improved maximum countermovement jump, which only persisted after 24 h in the vitamin group (p < 0.05). In both groups, squat jump height was significantly greater (p < 0.05) immediately after exercise and returned to baseline values after 24 h. The elastic index increased in the vitamin group (p < 0.05), but not in the placebo group. In both groups, lactate levels increased from pre- to immediately post-exercise (p < 0.05), and CK increased from pre- to 24 h post-exercise (p < 0.05). No significant differences between groups were observed in any of the variables (p > 0.05). Vitamin C and E supplementation does not seem to help with EIMD in endurance-trained individuals.

Influence of pistachios on force production, subjective ratings of pain, and oxidative stress following exercise-induced muscle damage in moderately trained athletes: A randomized, crossover trial

Although previous studies have focused on the role of pistachios on metabolic health, the ergogenic effects of the nut must be elucidated. This study evaluated the impact of ingesting raw, shelled, unsalted pistachios on subjective pain ratings, force production, vertical jump, and biochemical indices of recovery from eccentrically biased exercise. Using a crossover design, 27 moderately trained, male athletes completed 3 trials in a randomized counterbalanced fashion. Control received water only, low dose (1.5 oz/d; PL) and high dose (3.0 oz/d; PH) consumed pistachios for 2 weeks with a 3-4-week washout between trials. PH had lower pain ratings in most muscles after 72 h of recovery (p < 0.05). PH prevented a decrease in force production at 120°/s of knee flexion (p > 0.05); whereas force was diminished in the other trials. Creatine kinase, myoglobin, and C-reactive protein increased over time following exercise (p < 0.05); however, there were no advantages following pistachio consumption. No significant changes in vertical jump or superoxide dismutase were elicited during any trial. This study demonstrates that 3.0 oz/d of pistachios can reduce delayed onset of muscle soreness and maintain muscle strength, potentially promoting exercise tolerance and training adaptations.

ClinicalTrialsgov Identifier

NCT03698032.

THE VITAMIN E CONSUMPTION EFFECT ON MUSCLE DAMAGE AND OXIDATIVE STRESS: A SYSTEMATIC REVIEW AND META-ANALYSIS OF RANDOMIZED CONTROLLED TRIALS

ABSTRACT Introduction: Vitamin E supplementation may protect against exercise-induced muscle damage (EIMD) through possible inhibition of free radical formation and cell membrane stabilization. However, there is no systematic review of this topic. This fact maintains academic stalemates that may have a resolution. Objective: This systematic review with meta-analysis aims to provide a comprehensive literature review on the hypothesis of the benefit of vitamin E supplementation on oxidative stress and muscle damage induced by aerobic exercise. Methods: A random-effects model was used, weighted mean difference (WMD) and 95% confidence interval (CI) were applied to estimate the overall effect. Results: The results revealed a significant effect of vitamin E supplementation on reducing creatine kinase (CK) and lactate dehydrogenase (LDH). In addition, a subgroup analysis resulted in a significant decrease in CK concentrations in trials with immediate and <24 hours post-exercise CK measurement; <1000 at daily vitamin E intake; ≤1 at weekly intake; 1 at six weeks and >6 weeks experimental duration, studies on aerobic exercise and training were part of the crossover study. Conclusion: Vitamin E can be seen as a priority agent for recovery from muscle damage. Evidence Level II; Therapeutic Studies – Investigating the results.

Skeletal muscle oxidative stress and inflammation in aging: Focus on antioxidant and anti-inflammatory therapy

With aging, the progressive loss of skeletal muscle will have negative effect on multiple physiological parameters, such as exercise, respiration, thermoregulation, and metabolic homeostasis. Accumulating evidence reveals that oxidative stress and inflammation are the main pathological characteristics of skeletal muscle during aging. Here, we focus on aging-related sarcopenia, summarize the relationship between aging and sarcopenia, and elaborate on aging-mediated oxidative stress and oxidative damage in skeletal muscle and its critical role in the occurrence and development of sarcopenia. In addition, we discuss the production of excessive reactive oxygen species in aging skeletal muscle, which reduces the ability of skeletal muscle satellite cells to participate in muscle regeneration, and analyze the potential molecular mechanism of ROS-mediated mitochondrial dysfunction in aging skeletal muscle. Furthermore, we have also paid extensive attention to the possibility and potential regulatory pathways of skeletal muscle aging and oxidative stress mediate inflammation. Finally, in response to the abnormal activity of oxidative stress and inflammation during aging, we summarize several potential antioxidant and anti-inflammatory strategies for the treatment of sarcopenia, which may provide beneficial help for improving sarcopenia during aging.

Can melatonin be used as a potential antioxidant and sleep aid supplement for high-altitude travelers?

Traveling to high-altitude destinations is associated with risks such as high-altitude sicknesses and impaired sleep and performance. Although antioxidant supplementation may be beneficial, conflicting study results impede clear clinical guidelines. Herein, we highlight the potential of the antioxidant compound melatonin that is surprisingly poorly investigated in high-altitude settings.

Can Low-Dose of Dietary Vitamin E Supplementation Reduce Exercise-Induced Muscle Damage and Oxidative Stress? A Meta-Analysis of Randomized Controlled Trials

Vitamin E plays an important role in attenuating muscle damage caused by oxidative stress and inflammation. Despites of beneficial effects from antioxidant supplementation, effects of antioxidants on exercise-induced muscle damage are still unclear. The aim of this meta-analysis was to investigate the effects of dietary vitamin E supplementation on exercise-induced muscle damage, oxidative stress, and inflammation in randomized controlled trials (RCTs). The literature search was conducted through PubMed, Medline, Science Direct, Scopus, SPORTDiscuss, EBSCO, Google Scholar database up to February 2022. A total of 44 RCTs were selected, quality was assessed according to the Cochrane collaboration risk of bias tool (CCRBT), and they were analyzed by Revman 5.3. Dietary vitamin E supplementation had a protective effect on muscle damage represented by creatine kinase (CK; SMD −1.00, 95% CI: −1.95, −0.06) and lactate dehydrogenase (SMD −1.80, 95% CI: −3.21, −0.39). Muscle damage was more reduced when CK was measured immediately after exercise (SMD −1.89, 95% CI: −3.39, −0.39) and subjects were athletes (SMD −5.15, 95% CI: −9.92, −0.39). Especially vitamin E supplementation lower than 500 IU had more beneficial effects on exercise-induced muscle damage as measured by CK (SMD −1.94, 95% CI: −2.99, −0.89). In conclusion, dietary vitamin E supplementation lower than 500 IU could prevent exercise-induced muscle damage and had greater impact on athletes

Nutrients against Glucocorticoid-Induced Muscle Atrophy

Glucocorticoid excess is a critical factor contributing to muscle atrophy. Both endogenous and exogenous glucocorticoids negatively affect the preservation of muscle mass and function. To date, the most effective intervention to prevent muscle atrophy is to apply a mechanical load in the form of resistance exercise. However, glucocorticoid-induced skeletal muscle atrophy easily causes fatigue in daily physical activities, such as climbing stairs and walking at a brisk pace, and reduces body movements to cause a decreased ability to perform physical activity. Therefore, providing adequate nutrients in these circumstances is a key factor in limiting muscle wasting and improving muscle mass recovery. The present review will provide an up-to-date review of the effects of various nutrients, including amino acids such as branched-chain amino acids (BCAAs) and β–hydroxy β–methylbutyrate (HMB), fatty acids such as omega-3, and vitamins and their derivates on the prevention and improvement of glucocorticoid-induced muscle atrophy.

From skeletal muscle damage and regeneration to the hypertrophy induced by exercise: What is the role of different macrophages subsets?

Macrophages are one of the top players when considering immune cells involved with tissue homeostasis. Recently, increasing evidence has demonstrated that these macrophages could also present two major subsets during tissue healing; proliferative macrophages (M1-like), which are responsible for increasing myogenic cell proliferation, and restorative macrophages (M2-like), which are accountable for the end of the mature muscle myogenesis. The participation and characterization of these macrophage subsets is critical during myogenesis, not only to understand the inflammatory role of macrophages during muscle recovery but also to create supportive strategies that can improve mass muscle maintenance. Indeed, most of our knowledge about macrophage subsets comes from skeletal muscle damage protocols, and we still do not know how these subsets can contribute to skeletal muscle adaptation. This narrative review aims to collect and discuss studies demonstrating the involvement of different macrophage subsets during the skeletal muscle damage/regeneration process, showcasing an essential role of these macrophage subsets during muscle adaptation induced by acute and chronic exercise programs.

Physical Activity and Nutritional Influence on Immune Function: An Important Strategy to Improve Immunity and Health Status

Physical activity (PA) and nutrition are the essential components of a healthy lifestyle, as they can influence energy balance, promote functional ability of various systems and improve immunity. Infections and their associated symptoms are the common and frequent challenges to human health that are causing severe economic and social consequences around the world. During aging, human immune system undergoes dramatic aging-related changes/dysfunctions known as immunosenescence. Clinically, immunosenescence refers to the gradual deterioration of immune system that increases exposure to infections, and reduces vaccine efficacy. Such phenomenon is linked to impaired immune responses that lead to dysfunction of multiple organs, while lack of physical activity, progressive loss of muscle mass, and concomitant decline in muscle strength facilitate immunosenescence and inflammation. In the present review, we have discussed the role of nutrition and PA, which can boost the immune system alone and synergistically. Evidence suggests that long-term PA is beneficial in improving immune system and preventing various infections. We have further discussed several nutritional strategies for improving the immune system. Unfortunately, the available evidence shows conflicting results. In terms of interaction with food intake, PA does not tend to increase energy intake during a short time course. However, overcoming nutritional deficiencies appears to be the most practical recommendation. Through the balanced nutritious diet intake one can fulfill the bodily requirement of optimal nutrition that significantly impacts the immune system. Supplementation of a single nutrient as food is generally not advisable. Rather incorporating various fruits and vegetables, whole grains, proteins and probiotics may ensure adequate nutrient intake. Therefore, multi-nutrient supplements may benefit people having deficiency in spite of sufficient diet. Along with PA, supplementation of probiotics, bovine colostrum, plant-derived products and functional foods may provide additional benefits in improving the immune system.

Diet and redox state in maintaining skeletal muscle health and performance at high altitude

High altitude exposure leads to compromised physical performance with considerable weight loss. The major stressor at high altitude is hypobaric hypoxia which leads to disturbance in redox homeostasis. Oxidative stress is a well-known trigger for many high altitude illnesses and regulates several key signaling pathways under stressful conditions. Altered redox homeostasis is considered the prime culprit of high altitude linked skeletal muscle atrophy. Hypobaric hypoxia disturbs redox homeostasis through increased RONS production and compromised antioxidant system. Increased RONS disturbs the cellular homeostasis via multiple ways such as inflammation generation, altered protein anabolic pathways, redox remodeling of RyR1 that contributed to dysregulated calcium homeostasis, enhanced protein degradation pathways via activation calcium-regulated protein, calpain, and apoptosis. Ultimately, all the cellular signaling pathways aggregately result in skeletal muscle atrophy. Dietary supplementation of phytochemicals could become a safe and effective intervention to ameliorate skeletal muscle atrophy and enhance the physical performance of the personnel who are staying at high altitude regions. The present evidence-based review explores few dietary supplementations which regulate several signaling mechanisms and ameliorate hypobaric hypoxia induced muscle atrophy and enhances physical performance. However, a clinical research trial is required to establish proof-of-concept.

Broad Spectrum Polyphenol Supplementation from Tart Cherry Extract on Markers of Recovery from Intense Resistance Exercise

BACKGROUND

Tart cherry supplementation has been shown to enhance recovery from strenuous exercise due to its antioxidant properties. The majority of these studies used tart cherry juice, with a significant calorie content. The primary purpose of this study was to assess whether powdered tart cherry extract with minimal calorie content reduces oxidative stress and enhances recovery following intense resistance exercise.

METHODS

Thirteen men (mean age: 26.2 ± 5.3 years; height: 184.3 ± 8.2 cm; weight: 92.9 ± 15.6 kg) performed a demanding resistance exercise protocol consisting of 6 sets of 10 repetitions of barbell back squat with 80% 1RM. The protocol was performed once following 7 days of 500 mg of tart cherry extract and once following placebo. Serum protein carbonyl (PC) content, creatine kinase activity (CK) and creatine kinase myocardial band content (CK-MB) were used to assess oxidative stress, skeletal and cardiac muscle damage respectively. Muscle soreness was assessed by visual analog scale. Physical performance was measured by countermovement jump power and handgrip dynamometer strength.

RESULTS

There was a significant increase in PC in the placebo (PL) condition when compared to the Tart Cherry (TC) condition at Immediate Post (IP) (PL: 0.4 ± 0.3 vs. TC: - 0.4 ± 0.2 nmol∙mg^- 1; p < 0.001), 1 h (PL: 0.3 ± 0.3 vs. TC: - 0.7 ± 0.3 nmol∙mg^- 1; p < 0.001) and 24 h (PL: 0.1 ± 0.4 vs. TC: - 0.3 ± 0.5 nmol∙mg^- 1; p = 0.010). There was a significant increase in CK activity in PL when compared to the TC at IP (PL: 491.1 ± 280 vs. TC: 296.3 ± 178 U∙L^- 1; p = 0.008) and 3 h (PL: - 87 ± 123 vs. TC: 43.1 ± 105.3 U∙L^- 1; p = 0.006). There was a significant (p = 0.003) increase in CKMB concentration in PL when compared to the TC (PL: 21.6 ± 12.4 vs. TC: - 0.3 ± 11.8 ng∙ml^- 1; p = 0.006) at 1 h post. There was a significant increase in handgrip strength in TC when compared to PL (PL: - 2 ± 5.1 vs. TC: 1.7 ± 3 kg; p = 0.017) at 24 h post.

CONCLUSIONS

This study demonstrated that tart cherry extract reduced oxidative stress and markers of muscle and cardiac damage following intense resistance exercise. This occurred along with a prevention of the decrease in handgrip strength seen following the intense exercise protocol, indicating a potential reduction in central fatigue. These benefits were seen with minimal energy intake.

Marine phytoplankton improves recovery and sustains immune function in humans and lowers proinflammatory immunoregulatory cytokines in a rat model

Purpose

This study investigated the effects of marine phytoplankton supplementation (Oceanix®, Tetraselmis chuii) on 1) maximal isometric strength and immune function in healthy humans following a oneweek high-intensity resistance-training program and 2) the proinflammatory cytokine response to exercise in a rat model.

Methods

In the human trial, 22 healthy male and female participants were randomly divided into marine phytoplankton and placebo groups. Following baseline testing, participants underwent a 14-day supplement loading phase before completing five consecutive days of intense resistance training. In the rat model, rats were randomly divided into four groups (n=7 per condition): (i) control, (ii) exercise, (iii) exercise + marine phytoplankton (2.55 mg/kg/day), or (iv) exercise + marine phytoplankton (5.1 mg/kg/day). Rats in the exercising groups performed treadmill exercise 5 days per week for 6 weeks.

Results

In the human model, marine phytoplankton prevented significant declines in the isometric peak rate of force development compared to placebo. Additionally, salivary immunoglobulin A concentration was significantly lower following the resistance training protocol in the placebo group but not in the marine phytoplankton group. Marine phytoplankton in exercising rats decreased intramuscular levels and serum concentrations of tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1β) and intramuscular concentrations of malondialdehyde.

Conclusion

Marine phytoplankton prevented decrements in indices of functional exercise recovery and immune function. Mechanistically, these outcomes could be prompted by modulating the oxidative stress and proinflammatory cytokine response to exercise.

Vitamin E protects against gabapentin-induced chronic hepatic and renal damage associated with the inhibition of apoptosis and tissue injury in rats

AIMS

This study aimed to investigate the potential protective effects of vitamin E against gabapentin-induced chronic liver and kidney injury associated with the inhibition of biomarkers of apoptosis and tissue injury.

MATERIALS AND METHODS

Four groups of adult male rats were included; control, gabapentin (100 mg/kg/day), Vitamin E (80 mg/kg/day), and a combination of gabapentin and Vitamin E for 90 days. Serum levels of AST, ALT, LDH, ALP, urea, and creatinine were measured in addition to malondialdehyde (MDA), and reduced glutathione (GSH) tissue levels. P53 gene expression, histological, and immunohistochemical examinations were performed in liver and kidney tissue samples.

KEY FINDINGS

Gabapentin increased AST, ALT, LDH, ALP, urea, creatinine, MDA, and p53 gene expression and it reduced GSH. Moreover, gabapentin administration caused structural changes in the hepatic and renal architecture with a weak Periodic acid-Schiff (PAS) reaction that reflects glycogen deposition in the liver and kidney and a positive immunoreaction for BCL2-associated X protein (BAX) that reflects activated apoptosis. Vitamin E significantly (p<0.05) reversed the biochemical alterations associated with chronic gabapentin administration and improved the histopathological picture of hepatic and renal tissue with a partial inhibition of BAX.

SIGNIFICANCE

Chronic administration of gabapentin causes hepatic and renal impairments, which is ameliorated by Vitamin E; possibly due to the inhibition of biomarkers of apoptosis and tissue injury.

The Possible Importance of Glutamine Supplementation to Mood and Cognition in Hypoxia from High Altitude

Hypoxia induced by low O₂ pressure is responsible for several physiological and behavioral alterations. Changes in physiological systems are frequent, including inflammation and psychobiological declines such as mood and cognition worsening, resulting in increased reaction time, difficulty solving problems, reduced memory and concentration. The paper discusses the possible relationship between glutamine supplementation and worsening cognition mediated by inflammation induced by high altitude hypoxia. The paper is a narrative literature review conducted to verify the effects of glutamine supplementation on psychobiological aspects. We searched MEDLINE/PubMed and Web of Science databases and gray literature by Google Scholar for English articles. Mechanistic pathways mediated by glutamine suggest potential positive effects of its supplementation on mood and cognition, mainly its potential effect on inflammation. However, clinical studies are scarce, making any conclusions impossible. Although glutamine plays an important role and seems to mitigate inflammation, clinical studies should test this hypothesis, which will contribute to a better mood and cognition state for several people who suffer from problems mediated by hypoxia.

Antioxidants and Exercise Performance: With a Focus on Vitamin E and C Supplementation

Antioxidant supplementation, including vitamin E and C supplementation, has recently received recognition among athletes as a possible method for enhancing athletic performance. Increased oxidative stress during exercise results in the production of free radicals, which leads to muscle damage, fatigue, and impaired performance. Despite their negative effects on performance, free radicals may act as signaling molecules enhancing protection against greater physical stress. Current evidence suggests that antioxidant supplementation may impair these adaptations. Apart from athletes training at altitude and those looking for an immediate, short-term performance enhancement, supplementation with vitamin E does not appear to be beneficial. Moreover, the effectiveness of vitamin E and C alone and/or combined on muscle mass and strength have been inconsistent. Given that antioxidant supplements (e.g., vitamin E and C) tend to block anabolic signaling pathways, and thus, impair adaptations to resistance training, special caution should be taken with these supplements. It is recommended that athletes consume a diet rich in fruits and vegetables, which provides vitamins, minerals phytochemicals, and other bioactive compounds to meet the recommended intakes of vitamin E and C.

Muscle Injury in Bodybuilding Based on Mesoporous Multifunctional Nanomaterials for Sports Rehabilitation Training

As an important means of treating diseases, chemical-based drugs have always guaranteed people’s health and longevity. However, due to the nature of some drugs, their use in the medical field is limited. This study mainly discusses the treatment of muscle damage based on sports rehabilitation training mesoporous multifunctional nanomaterials in bodybuilding. The biological characteristics of the targeted control of mesoporous multifunctional nanomaterials for target drugs were studied by analyzing the regeneration of skeletal muscles of mice after gastrocnemius strain under computer control. The electrostatic interactions modified by the consensus binding between AS1411 and Dimer-PPTcDA on the surface of mesoporous silicon are used to block the pores, and the release of objective molecules depends on the concentration of the drug in the tendon cells and the time of action. In this system, AS1411 has both the characteristics of the target substance and the active site of the targeted stimulus response in the cell. After FAM is labeled AS1411, the fluorescence of FAM can be used to monitor the release of the drug in real time, so as to directly release the drug to the lesion, maintain local effectiveness, and greatly improve the biological activity of the drug. In addition, in the safety analysis of mesoporous multifunctional nanomaterials on cells, if the concentration of nanoparticles is 90 μg/mL, the cell survival rate is almost 100%. The results show that the mesoporous multifunctional nanomaterials have low cytotoxicity and cell activity is not affected. The smaller the particle size of mesoporous silicon, the easier it is to invade the focus cells. In addition, confocal microscopy imaging has also effectively demonstrated the targeting effect of mesoporous multifunctional nanomaterials on cells.

Effects of Hyperbaric Oxygen Therapy on Inflammation, Oxidative/Antioxidant Balance, and Muscle Damage after Acute Exercise in Normobaric, Normoxic and Hypobaric, Hypoxic Environments: A Pilot Study

The purpose of this study was to investigate the effects of hyperbaric oxygen therapy (HBOT) on inflammation, the oxidative/antioxidant balance, and muscle damage after acute exercise in normobaric, normoxic (NN) and hypobaric, hypoxic (HH) environments. Eighteen healthy males were selected and randomly assigned to three groups: exercise in NN conditions (NN group, n = 6), HBOT treatment after exercise in NN conditions (HNN group, n = 6), and HBOT treatment after exercise in HH conditions (HHH group, n = 6). All subjects performed treadmill running for 60 min at 75–80% maximum heart rate (HRmax) exercise intensity under each condition. The HBOT treatments consisted of breathing 100% oxygen at 2.5 atmosphere absolute (ATA) for 60 min. Blood samples were collected before exercise (BE), after exercise (AE), and after HBOT (AH) to examine inflammation (fibrinogen, interleukin-6 [IL-6], and tumor necrosis factor-α (TNF-α)), the oxidative/antioxidant balance (derivatives of reactive oxygen metabolites (d-ROMs) and the biological antioxidant potential (BAP)), and muscle damage (creatine kinase (CK) and lactate dehydrogenase (LDH)). Plasma fibrinogen, serum IL-6, CK, and LDH levels were significantly increased AE compared to BE in all groups (p < 0.05). Plasma fibrinogen levels were significantly decreased AH compared to AE in all groups (p < 0.05), and the HNN group had a significantly lower AH compared to BE (p < 0.05). Serum IL-6 levels were significantly decreased AH compared to AE in the HNN and HHH groups (p < 0.05). Serum CK levels were significantly decreased AH compared to AE in the HHH group (p < 0.05). Serum LDH levels were significantly decreased AH compared to AE in the HNN and HHH groups (p < 0.05), and the NN and HNN groups had significantly higher AH serum LDH levels compared to BE (p < 0.05). These results suggest that acute exercise in both the NN and HH environments could induce temporary inflammatory responses and muscle damage, whereas HBOT treatment may be effective in alleviating exercise-induced inflammatory responses and muscle damage.

The Molecular Adaptive Responses of Skeletal Muscle to High-Intensity Exercise/Training and Hypoxia

High-intensity exercise/training, especially interval exercise/training, has gained popularity in recent years. Hypoxic training was introduced to elite athletes half a century ago and has recently been adopted by the general public. In the current review, we have summarised the molecular adaptive responses of skeletal muscle to high-intensity exercise/training, focusing on mitochondrial biogenesis, angiogenesis, and muscle fibre composition. The literature suggests that (peroxisome proliferator-activated receptor gamma coactivator 1-alpha) PGC-1α, vascular endothelial growth factor (VEGF), and hypoxia-inducible factor 1-alpha (HIF1-α) might be the main mediators of skeletal muscle adaptations to high-intensity exercises in hypoxia. Exercise is known to be anti-inflammatory, while the effects of hypoxia on inflammatory signalling are more complex. The anti-inflammatory effects of a single session of exercise might result from the release of anti-inflammatory myokines and other cytokines, as well as the downregulation of Toll-like receptor signalling, while training-induced anti-inflammatory effects may be due to reductions in abdominal and visceral fat (which are main sources of pro-inflammatory cytokines). Hypoxia can lead to inflammation, and inflammation can result in tissue hypoxia. However, the hypoxic factor HIF1-α is essential for preventing excessive inflammation. Disease-induced hypoxia is related to an upregulation of inflammatory signalling, but the effects of exercise-induced hypoxia on inflammation are less conclusive. The effects of high-intensity exercise under hypoxia on skeletal muscle molecular adaptations and inflammatory signalling have not been fully explored and are worth investigating in future studies. Understanding these effects will lead to a more comprehensive scientific basis for maximising the benefits of high-intensity exercise.

Do Antioxidant Vitamins Prevent Exercise-Induced Muscle Damage? A Systematic Review

Free radicals produced during exercise play a role in modulating cell signaling pathways. High doses of antioxidants may hamper adaptations to exercise training. However, their benefits are unclear. This review aims to examine whether vitamin C (VitC) and/or vitamin E (VitE) supplementation (SUP) prevents exercise-induced muscle damage. The PubMed, Web of Science, Medline, CINAHL, and SPORTDiscus databases were searched, and 21 articles were included. Four studies examined the effects of acute VitC SUP given pre-exercise: in one study, lower CK levels post-exercise was observed; in three, no difference was recorded. In one study, acute VitE SUP reduced CK activity 1 h post-exercise in conditions of hypoxia. In three studies, chronic VitE SUP did not reduce CK activity after an exercise session. Chronic VitE SUP did not reduce creatine kinase (CK) concentrations after three strength training sessions, but it was effective after 6 days of endurance training in another study. Chronic SUP with VitC + E reduced CK activity post-exercise in two studies, but there was no such effect in four studies. Finally, three studies described the effects of chronic VitC + E SUP and long-term exercise, reporting dissimilar results. To conclude, although there is some evidence of a protective effect of VitC and/or VitE against exercise-induced muscle damage, the available data are not conclusive.

Form of Vitamin E Supplementation Affects Oxidative and Inflammatory Response in Exercising Horses

Vitamin E is an essential antioxidant that may benefit athletes by reducing oxidative stress and influencing cytokine expression. Supplements can be derived from natural or manufactured synthetic sources. This study aimed to determine (1) if supplemental vitamin E is beneficial to exercising horses and (2) if there is a benefit of natural versus synthetic vitamin E. After 2 weeks on the control diet (vitamin E-deficient grain and hay), 18 horses were divided into three groups and fed the control diet plus (1) 1000 IU/d synthetic α-tocopherol (SYN-L), (2) 4000 IU/d synthetic α-tocopherol (SYN-H), or (3) 4000 IU/d RRR-α-tocopherol (natural source [NAT]). On day 7, horses began a 6-week training protocol, with standard exercise tests (SETs) performed before and after the 6-week protocol. Venous blood samples were collected on days 0, 7, 29, and 49. Horses fed NAT had higher α-tocopherol (P < .05) at post-SET1 through post-SET2. Plasma thiobarbituric acid-reactive substance levels were lower in NAT versus SYN-L horses after SET2 (P = .02). Serum aspartate aminotransferase was lower after exercise in NAT horses versus SYN-L and SYN-H (P = .02), and less reduction in stride duration was seen after exercise in NAT as compared with SYN-L and SYN-H (P = .02). Gene expression of tumor necrosis factor α was lower in NAT compared with SYN-H (P = .01) but not SYN-L. In conclusion, feeding higher levels of natural vitamin E source resulted in higher serum α-tocopherol levels as well as some improvement in oxidative and inflammatory response and improved functional outcomes in response to an exercise test.

Inhibition of Osteocyte Membrane Repair Activity via Dietary Vitamin E Deprivation Impairs Osteocyte Survival

Osteocytes experience plasma membrane disruptions (PMD) that initiate mechanotransduction both in vitro and in vivo in response to mechanical loading, suggesting that osteocytes use PMD to sense and adapt to mechanical stimuli. PMD repair is crucial for cell survival; antioxidants (e.g., alpha-tocopherol, also known as Vitamin E) promote repair while reactive oxygen species (ROS), which can accumulate during exercise, inhibit repair. The goal of this study was to determine whether depleting Vitamin E in the diet would impact osteocyte survival and bone adaptation with loading. Male CD-1 mice (3 weeks old) were fed either a regular diet (RD) or Vitamin E-deficient diet (VEDD) for up to 11 weeks. Mice from each dietary group either served as sedentary controls with normal cage activity, or were subjected to treadmill exercise (one bout of exercise or daily exercise for 5 weeks). VEDD-fed mice showed more PMD-affected osteocytes (+ 50%) after a single exercise bout suggesting impaired PMD repair following Vitamin E deprivation. After 5 weeks of daily exercise, VEDD mice failed to show an exercise-induced increase in osteocyte PMD formation, and showed signs of increased osteocytic oxidative stress and impaired osteocyte survival. Surprisingly, exercise-induced increases in cortical bone formation rate were only significant for VEDD-fed mice. This result may be consistent with previous studies in skeletal muscle, where myocyte PMD repair failure (e.g., with muscular dystrophy) initially triggers hypertrophy but later leads to widespread degeneration. In vitro, mechanically wounded MLO-Y4 cells displayed increased post-wounding necrosis (+ 40-fold) in the presence of H2O2, which could be prevented by Vitamin E pre-treatment. Taken together, our data support the idea that antioxidant-influenced osteocyte membrane repair is a vital aspect of bone mechanosensation in the osteocytic control of PMD-driven bone adaptation.

Targeting myomiRs by tocotrienol-rich fraction to promote myoblast differentiation

Background

Several muscle-specific microRNAs (myomiRs) are differentially expressed during cellular senescence. However, the role of dietary compounds on myomiRs remains elusive. This study aimed to elucidate the modulatory role of tocotrienol-rich fraction (TRF) on myomiRs and myogenic genes during differentiation of human myoblasts. Young and senescent human skeletal muscle myoblasts (HSMM) were treated with 50 μg/mL TRF for 24 h before and after inducing differentiation.

Results

The fusion index and myotube surface area were higher (p < 0.05) on days 3 and 5 than that on day 1 of differentiation. Ageing reduced the differentiation rate, as observed by a decrease in both fusion index and myotube surface area in senescent cells (p < 0.05). Treatment with TRF significantly increased differentiation at days 1, 3 and 5 of young and senescent myoblasts. In senescent myoblasts, TRF increased the expression of miR-206 and miR-486 and decreased PTEN and PAX7 expression. However, the expression of IGF1R was upregulated during early differentiation and decreased at late differentiation when treated with TRF. In young myoblasts, TRF promoted differentiation by modulating the expression of miR-206, which resulted in the reduction of PAX7 expression and upregulation of IGF1R.

Conclusion

TRF can potentially promote myoblast differentiation by modulating the expression of myomiRs, which regulate the expression of myogenic genes.

Association of Healthy Eating Index and oxidative stress in adolescent volleyball athletes and non-athletes

OBJECTIVES

The objective of this study was to compare the relationship between the Healthy Eating Index and oxidative stress parameters in adolescent athletes and non-athletes.

METHODS

A cross-sectional study was carried out with 18 adolescent male and female volleyball athletes who were paired with 15 adolescent non-athletes. Body fat percentage, food intake, free radical production, antioxidant enzyme activity, and thiol and protein damage were measured.

RESULTS

In the Healthy Eating Index assessment, the food quality of 72.7% of the sample was classified as low, and no participant was found to have good food quality. The mean intake of vitamins A and E was below recommendations in both groups and sexes; however vitamin C intake was appropriate for the age group. Increased free radical production was observed in the athletes' erythrocytes (p<0.001), accompanied by lower levels of plasma reduced glutathione (p = 0.01), but there were no correlations between Healthy Eating Index and oxidative stress parameters or between body composition, vitamin A, C and E intake and oxidative stress.

CONCLUSIONS

The sample's diet quality was classified as low and, despite the fact that there was greater production of free radicals in the athletes' erythrocytes and plasma, in addition to lower levels of plasma reduced glutathione , there was no correlation between Healthy Eating Index and oxidative stress.

Protein O-GlcNAc Modification Increases in White Blood Cells After a Single Bout of Physical Exercise

Background

Protein O-linked N-acetylglucosamine (O-GlcNAc) is a dynamic posttranslational modification influencing the function of many intracellular proteins. Recently it was revealed that O-GlcNAc regulation is modified under various stress states, including ischemia and oxidative stress. Aside from a few contradictory studies based on animal models, the effect of exercise on O-GlcNAc is unexplored.

Purpose

To evaluate O-GlcNAc levels in white blood cells (WBC) of human volunteers following physical exercise.

Methods

Young (age 30 ± 5.2), healthy male volunteers (n = 6) were enlisted for the study. Blood parameters including metabolites, ions, “necro”-enzymes, and cell counts were measured before and after a single bout of exercise (2-mile run). From WBC samples, we performed western blots to detect O-GlcNAc modified proteins. The distribution of O-GlcNAc in WBC subpopulations was assessed by flow cytometry.

Results

Elevation of serum lactic acid (increased from 1.3 ± 0.4 to 6.9 ± 1.7 mM), creatinine (from 77.5 ± 6.3 U/L to 102.2 ± 7.0 μM), and lactate dehydrogenase (from 318.5 ± 26.2 to 380.5 ± 33.2 U/L) confirmed the effect of exercise. WBC count also significantly increased (from 6.6 ± 1.0 to 8.4 ± 1.4 G/L). The level of O-GlcNAc modified proteins in WBCs showed significant elevation after exercise (85 ± 51%, p < 0.05). Flow cytometry revealed that most of this change could be attributed to lymphocytes and monocytes.

Conclusion

Our results indicate that short-term exercise impacts the O-GlcNAc status of WBCs. O-GlcNAc modification could be a natural process by which physical activity modulates the immune system. Further research could elucidate the role of O-GlcNAc during exercise and validate O-GlcNAc as a biomarker for fitness assessment.

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.

Potential Role of L-Arginine and Vitamin E Against Bone Loss Induced by Nano-Zinc Oxide in Rats

The purpose of this study was to illustrate the effects of zinc oxide nanoparticles (ZnO-NPs) administration on bone turnover and bone resorbing agents in rats and how L-arginine (L-arg) or vitamin E (vit E) co-administrations might affect them. Fasting rats were randomly divided into four groups (n = 10): G1-normal healthy animals; G2-ZnO-NPs-exposed rats (600 mg/kg^-1/day^-1); G3-ZnO-NPs-exposed rats co-administrated L-arg (200 mg/kg^-1/day^-1); G4-ZnO-NPs-exposed rats co-administrated vit E (200 mg/kg^-1/day^-1). The ingredients were orally administered daily. The body weight and food consumption of rats were recorded during the administration period and the experiment continued for three consecutive weeks. The results demonstrated that ZnO-NPs administration induced bone loss in rats as manifested by reduced activity of bone alkaline phosphatase (B-ALP) and increased level of C-terminal peptide type I collagen (CTx). The increase of inflammatory markers, tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) by ZnO-NPs suggests that deleterious effects of ZnO-NPs on bone turnover were, in part, due to inflammation. Confirming to this suggestion, both L-arg and vit E reduced TNF-α and IL-6 levels and consequently decreased bone resorption as indicated by reduced serum CTx level. This study proved that ZnO-NPs can induce bone turnover, which may be reduced by L-arg or vit.E co-administration, partly by anti-inflammatory mechanism.

Moderate exercise increases endotoxin concentration in hypoxia but not in normoxia: A controlled clinical trial

BACKGROUND

Hypoxia and high altitudes affect various organs, which impairs important physiological functions, such as a disruption of the intestinal barrier mediated by increased translocation of bacteria and increased circulating endotoxin levels. Physical exercise can alter endotoxin concentration in normoxia. The aim of this study is to evaluate the effects of moderate exercise on endotoxin concentration in normobaric hypoxia.

METHODS

Nine healthy male volunteers exercised on a treadmill for 60 minutes at an intensity of 50% VO2peak in normoxic or hypoxic conditions (4200 m). Blood was collected at rest, immediately after exercise and 1 hour after exercise to evaluate serum endotoxin levels.

RESULTS

Under hypoxic exercise conditions, SaO2% saturation was lower after exercise compared with resting levels (P < 0.05) and returned to the resting level during recovery in normoxia (P < 0.05). Endotoxin concentration increased after exercise in hypoxia (P < 0.05); it remained high 1 hour after exercise in hypoxia compared with normoxia (P < 0.05) and was higher after exercise and recovery compared with resting levels (P < 0.05). HR was higher during exercise in relation basal in both conditions (P < 0.05) and RPR increase after 60 minutes in comparison to 20 minutes in hypoxia (P < 0.05).

CONCLUSION

Moderate exercise performed in hypoxia equivalent to 4200 m increased endotoxin plasma concentration after exercise. One hour of rest in normoxic conditions was insufficient for the recovery of circulating endotoxins.