Inflammatory Status, Intgracellular Signaling in Skeletal Muscle, Skeletal Muscle Damage, Skeletal Muscle Performance
Conditions
Keywords
aseptic inflammation, skeletal muscle function, exercise
Brief summary
In this investigation the investigators utilized NAC administration to foster GSH availability during an 8-day period following eccentric exercise-induced muscle damage in order to test our hypotheses: i) antioxidant supplementation does not disturb performance and adaptations induced by exercise-induced muscle injury and ii) redox status perturbations in skeletal muscle are pivotal for the regulation of muscle' inflammatory response and repair.
Detailed description
The major thiol-disulfide couple of reduced (GSH) and oxidized glutathione (GSSG) is a key-regulator of major transcriptional pathways regulating aseptic inflammation and recovery of skeletal muscle following aseptic injury. Antioxidant supplementation may hamper exercise-induced cellular adaptations. Our objective was to examine how thiol-based antioxidant supplementation affects skeletal muscle's performance and redox-sensitive signalling during the inflammatory and repair phases associated with exercise-induced micro-trauma.In a double-blind, counterbalanced design, 12 men received placebo (PLA) or N-acetylcysteine (NAC, 20 mg/kg/day) following muscle-damaging exercise (300 eccentric contractions). In each trial, muscle performance was measured at baseline, post-exercise, 2h post-exercise and daily for 8 consecutive days. Muscle biopsies from vastus lateralis and blood samples were collected pre-exercise and 2h, 2d, and 8d post-exercise.
Interventions
DIETARY_SUPPLEMENTn-acetylcysteine supplementation
n-acetylcysteine administration: 20 mg//kg/day, orally, daily for eight days following exercise placebo administration: 500 mL orally, daily for eight days following exercise
Sponsors
Democritus University of Thrace
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
BASIC_SCIENCE
Masking
DOUBLE (Subject, Outcomes Assessor)
Eligibility
Sex/Gender
MALE
Age
18 Years to 30 Years
Healthy volunteers
Yes
Inclusion criteria
a) recreationally trained as evidenced by their maximal oxygen consumption levels (VO2max \>45 ml/kg/min), b) were engaged in systematic exercise at least three times/week for ≥12 months), c) non-smokers, d) abstained from any vigorous physical activity during the study, e)abstained from consumption of caffeine, alcohol, performance-enhancing or antioxidant supplements, and medications during the study.
Exclusion criteria
a) a known NAC intolerance or allergy, b) a recent febrile illness, c) history of muscle lesion, d) lower limb trauma
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in tumor necrosis factor α in muscle | one hour before exercise, 2 hours post-exercise, 2 days post-exercise, 8 days post-exercise | Protein levels of TNF-α in vastus lateralis muscle |
| Change in testosterone concentration in plasma | one hour before exercise, 5 minutes post-exercise, 2 hours post-exercise, daily for 8 days post-exercise | — |
| Change in cytokine concentration in plasma | one hour before exercise, 5 minutes post-exercise, 2 hours post-exercise, daily for 8 days post-exercise | Measurement of IL-1β, IL-4, IL-6, TNF-α, IL-8, IL-10, IL-12p70 concentrations in plasma |
| Change in adhesion molecule concentration in blood | one hour before exercise, 5 minutes post-exercise, 2 hours post-exercise, daily for 8 days post-exercise | Measurement of ICAM-1, VCAM-1, sP-selectin, sE-selectin concentrations in plasma |
| Change in intracellular signalling proteins in muscle | one hour before exercise, 2 hours post-exercise, 2 days post-exercise, 8 days post-exercise | Measurement of phosphorylation levels of protein kinase B (Akt), mammalian target of rapamycin (mTOR), serine/threonine kinase (p70S6K), ribosomal protein S6 (rpS6), nuclear factor κB (NFκB), serine⁄threonine mitogen activated protein kinase (p38-MAPK) in vastus lateralis muscle. |
| Change in myogenic determination factor (MyoD) protein levels in muscle | one hour before exercise, 2 hours post-exercise, 2 days post-exercise, 8 days post-exercise | MyoD expression in vastus lateralis muscle |
| Change in reduced glutathione in blood | one hour before exercise, 5 minutes post-exercise, 2 hours post-exercise, daily for 8 days post-exercise | Concentration of reduced glutathione in red blood cells |
| Change in reduced glutathione in muscle | one hour before exercise, 2 hours post-exercise, 2 days post-exercise, 8 days post-exercise | concentration of reduced glutathione in quadriceps skeletal muscle group |
| Change in protein carbonyls in red blood cells and serum | one hour before exercise, 5 minutes post-exercise, 2 hours post-exercise, daily for 8 days post-exercise | concentration of protein carbonyls |
| Change in protein carbonyls in muscle | one hour before exercise, 2 hours post-exercise, 2 days post-exercise, 8 days post-exercise | protein carbonyl concentration in vastus lateralis skeletal muscle |
| Change in thiobarbituric acid reactive substances in red blood cells and serum | one hour before exercise, 5 minutes post-exercise, 2 hours post-exercise, daily for 8 days post-exercise | thiobarbituric acid reactive substances concentration in serum and red blood cells |
| Change in thiobarbituric acid reactive substances in muscle | one hour before exercise, 2 hours post-exercise, 2 days post-exercise, 8 days post-exercise | thiobarbituric acid reactive substances concentration in vastus lateralis skeletal muscle |
| Change in oxidized glutathione in red blood cells and blood | one hour before exercise, 5 minutes post-exercise, 2 hours post-exercise, daily for 8 days post-exercise | Concentration of oxidized glutathione in red blood cells and whole blood |
| Change in total antioxidant capacity in serum | one hour before exercise, 5 minutes post-exercise, 2 hours post-exercise, daily for 8 days post-exercise | — |
| Change in oxidized glutathione in muscle | one hour before exercise, 2 hours post-exercise, 2 days post-exercise, 8 days post-exercise | concentration of oxidized glutathione in vastus lateralis skeletal muscle |
| Change in catalase activity in red blood cells and serum | one hour before exercise, 5 minutes post-exercise, 2 hours post-exercise, daily for 8 days post-exercise | — |
| Change in glutathione peroxidase activity in red blood cells | one hour before exercise, 5 minutes post-exercise, 2 hours post-exercise, daily for 8 days post-exercise | — |
| Change in creatine kinase activity in plasma | one hour before exercise, 5 minutes post-exercise, 2 hours post-exercise, daily for 8 days post-exercise | — |
| Change in C-reactive protein in plasma | one hour before exercise, 5 minutes post-exercise, 2 hours post-exercise, daily for 8 days post-exercise | — |
| Change in macrophage infiltration in muscle | one hour before exercise, 2 hours post-exercise, 2 days post-exercise, 8 days post-exercise | — |
| Change in white blood cell count in blood | one hour before exercise, 5 minutes post-exercise, 2 hours post-exercise, daily for 8 days post-exercise | — |
| Change in neutrophil count in blood | one hour before exercise, 5 minutes post-exercise, 2 hours post-exercise, daily for 8 days post-exercise | — |
| Change in fatty acid binding protein in plasma | one hour before exercise, 5 minutes post-exercise, 2 hours post-exercise, daily for 8 days post-exercise | — |
| Change in cortisol concentration in blood | one hour before exercise, 5 minutes post-exercise, 2 hours post-exercise, daily for 8 days post-exercise | — |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Body composition | One day before exercise | Assessment of percent (%) lean body mass. |
| Maximal aerobic capacity | One day before exercise | Assessment of maximal oxygen consumption, an indice of cardiovascular conditioning |
| Change in profile of dietary intake | one hour before exercise, daily for 8 days post-exercise | Assessment of dietary intake with emphasis on antioxidant element intake |
| Change in side effect occurence | one hour before exercise, daily for 8 days post-exercise | The prevalence of potential side-effects (such as headaches or abdominal pain or any other discomfort) was monitored using a subjective 0-10 side-effects scale on a daily bases by an unblinded investigator (for ethical reasons). |
| Change in muscle function of knee extensor and flexor muscle | one hour before exercise, 5 minutes post-exercise, 2 hours post-exercise, daily for 8 days post-exercise | assessment of muscle peak and mean torque of knee extensors and flexors on an isokinetic dynamometer at 0, 90 and 180 degrees/sec |
Countries
Greece
Outcome results
None listed