Redox Status and Immune Function

Study Overview
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Brief Summary
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In this investigation the investigators utilized N-acetylcysteine (NAC) supplementation to enhance reduced glutathione (GSH) stores during an 8-day recovery period from a strenuous eccentric exercise protocol in order to test the hypotheses: i) redox status perturbations in skeletal muscle are pivotal for the immune responses and ii) antioxidant supplementation may alter immune cell responses following exercise-induced muscle microtrauma.

Detailed Description
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The major thiol-disulfide couple of GSH and oxidized glutathione (GSSG) is a crucial regulator of the main transcriptional pathways regulating aseptic inflammation and recovery of skeletal muscle following aseptic injury. Antioxidant supplementation may hamper exercise-induced inflammatory responses. The objective was to examine how thiol-based antioxidant supplementation affects immune mobilization following exercise-induced skeletal muscle microtrauma. In 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 assessment were performed pre-exercise, 2h post-exercise and daily for 8 consecutive days.

Official Title
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Evidence of a Redox-dependent Regulation of Immune Responses to Exercise-Induced Inflammation

Conditions
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Skeletal Muscle Damage, Aseptic Inflammation, Skeletal Muscle Function

Intervention / Treatment
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* Dietary Supplement: n-acetylcysteine
* Dietary Supplement: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Recreationally trained (VO2max > 45 ml/kg/min) Engaged in regular exercise for ≥3 times/week for > 12 months non-smokers Abstain from exercise during the course of the two trials No consumption of performance-enhancing substances, antioxidants, caffeine, alcohol and/or medications during the study. Exclusion Criteria: NAC intolerance Recent musculoskeletal injuries of the lower limbs Febrile illness History of muscle lesion.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 30 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: n-acetylcysteine<br>orally in three daily dosages, at 20 mg/kg/day, daily for eight days after exercise | Dietary Supplement: n-acetylcysteine<br>* 20 mg//kg/day, orally, daily for eight days following exercise<br>* Other names: NAC;|
| Active Comparator: Placebo<br>orally in three daily dosages, content: 500 mL drink that contained water (375 mL), sugar-free cordial (125 ml), and 2 g of low-calorie glucose/dextrose powder | Dietary Supplement: Placebo<br>* 500 mL orally, daily for eight days following exercise<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in protein carbonyls in red blood cells | Concentration of protein carbonyls | Pre-exercise, 2 hours post-exercise, daily for 8 consecutive days post-exercise | 
| Changes in thiobarbituric acid reactive substances in red blood cells | Thiobarbituric acid reactive substances concentration in red blood cells | Pre-exercise, 2 hours post-exercise, daily for 8 consecutive days post-exercise | 
| Changes in total antioxidant capacity in serum |  | Pre-exercise, 2 hours post-exercise, daily for 8 consecutive days post-exercise | 
| Changes in reduced glutathione in blood | Concentration of reduced glutathione in red blood cells | Pre-exercise, 2 hours post-exercise, daily for 8 consecutive days post-exercise | 
| Changes in oxidized glutathione in blood | Concentration of oxidized glutathione in red blood cells | Pre-exercise, 2 hours post-exercise, daily for 8 consecutive days post-exercise | 
| Changes in catalase activity in red blood cells |  | Pre-exercise, 2 hours post-exercise, daily for 8 consecutive days post-exercise | 
| Changes in creatine kinase activity in serum |  | Pre-exercise, 2 hours post-exercise, daily for 8 consecutive days post-exercise | 
| Changes in high sensitivity C-reactive protein in serum |  | Pre-exercise, 2 hours post-exercise, 1 day post-exercise, 2 days post-exercise, 3 days post-exercise | 
| Changes in white blood cell count in blood |  | Pre-exercise, 2 hours post-exercise, daily for 8 consecutive days post-exercise | 
| Changes in adhesion molecule concentration in blood | Measurement of soluble vascular cell adhesion molecule-1 (sVCAM-1) and soluble intercellular cell adhesion molecule-1 (sICAM-1) concentrations in plasma | Pre-exercise, 2 hours post-exercise, 1 day post-exercise, 2 days post-exercise, 3 days post-exercise | 
| Changes in cytokine concentration in serum | Measurement of interleukin-1β (IL-1β) and interleukin-6 (IL-6) | Pre-exercise, 2 hours post-exercise, 1 day post-exercise, 2 days post-exercise, 3 days post-exercise, 8 days post-exercise | 
| Changes in neutrophil count in blood | Cytofluorometric analysis of neutrophil count in blood | Pre-exercise, 2 hours post-exercise, daily for 8 consecutive days post-exercise | 
| Changes in lymphocyte count in blood | Cytofluorometric analysis of lymphocyte count in blood | Pre-exercise, 2 hours post-exercise, daily for 8 consecutive days post-exercise | 
| Changes in monocyte count in blood | Cytofluorometric analysis of monocyte count in blood | Pre-exercise, 2 hours post-exercise, daily for 8 consecutive days post-exercise | 
| Changes in basophil count in blood | Cytofluorometric analysis of baseophil count in blood | Pre-exercise, 2 hours post-exercise, daily for 8 consecutive days post-exercise | 
| Changes in eosinophil count in blood | Cytofluorometric analysis of eosinophil count in blood | Pre-exercise, 2 hours post-exercise, daily for 8 consecutive days post-exercise | 
| Changes in T-helper cell count in blood | Cytofluorometric analysis of T-helper cell count in blood | Pre-exercise, 2 hours post-exercise, daily for 8 consecutive days post-exercise | 
| Changes in T cytotoxic cell count in blood | Cytofluorometric analysis of T cytotoxic cell count in blood | Pre-exercise, 2 hours post-exercise, daily for 8 consecutive days post-exercise | 
| Changes in natural killer-T (NK-T) cell count in blood | Cytofluorometric analysis of NK-T cell count in blood | Pre-exercise, 2 hours post-exercise, daily for 8 consecutive days post-exercise | 
| Changes in 62L macrophage count in blood | Cytofluorometric analysis of 62L macrophage count in blood | Pre-exercise, 2 hours post-exercise, daily for 8 consecutive days post-exercise | 
| Changes in B lympho cell count in blood | Cytofluorometric analysis of B lympho cell count in blood | Pre-exercise, 2 hours post-exercise, daily for 8 consecutive days post-exercise | 
| Changes in natural killer (NK) cell count in blood | Cytofluorometric analysis of natural killer cell count in blood | Pre-exercise, 2 hours post-exercise, daily for 8 consecutive days post-exercise | 
| Changes in macrophage count in blood | Cytofluorometric analysis of macrophage count in blood | Pre-exercise, 2 hours post-exercise, daily for 8 consecutive days post-exercise | 
| Changes in HLA+/Macr+ macrophage count in blood | Cytofluorometric analysis of HLA+/Macr+ count in blood | Pre-exercise, 2 hours post-exercise, daily for 8 consecutive days post-exercise | 
| Changes in 11B+ macrophage count in blood | Cytofluorometric analysis of 11B+ macrophage count in blood | Pre-exercise, 2 hours post-exercise, daily for 8 consecutive days post-exercise | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in muscle performance | Assessment of maximal knee extensor eccentric peak torque on an isokinetic dynamometer at 60o/s. | Pre-exercise, 2 hours post-exercise, daily for 8 consecutive days post-exercise | 
| Changes in delayed onset of muscle soreness | Assessment of the delayed onset of muscle soreness by palpation of the vastus lateralis and rectus femoris following a squat motion | Pre-exercise, 2 hours post-exercise, daily for 8 consecutive days post-exercise | 
| Maximal aerobic capacity | Assessment of maximal oxygen consumption | One day before exercise | 
| Body composition | Measurement of body composition by Dual Emission X-ray Absorptiometry (DXA) | One day before exercise | 
| Changes in dietary intake profile | Assessment of dietary intake with emphasis on antioxidant element intake | One day before exercise and daily for 8 consecutive days post-exercise | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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muscle injury, exercise, redox status, immune cells