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NCT Number: NCT01778309

NAC Supplementation and Skeletal Muscle Performance

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.

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Key information

Conditions

Skeletal Muscle Damage Behavior Inflammatory Status Intgracellular Signaling in Skeletal Muscle Motor Activity Skeletal Muscle Performance

Age range

18 year–30 year

Sex eligibility

Male

Study type

Interventional

Phase

Not applicable

Primary location

Laboratory of Physical Education & Sport Performance

Komotini, Thrace, 69100, Greece

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

n-acetylcysteine supplementation

Dietary Supplement

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

Other names: Exercise-induced skeletal muscle damage

Primary outcomes

  1. Change in reduced glutathione in blood

    Time frame: 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

  2. Change in reduced glutathione in muscle

    Time frame: 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

  3. Change in protein carbonyls in red blood cells and serum

    Time frame: one hour before exercise, 5 minutes post-exercise, 2 hours post-exercise, daily for 8 days post-exercise

    concentration of protein carbonyls

  4. Change in protein carbonyls in muscle

    Time frame: one hour before exercise, 2 hours post-exercise, 2 days post-exercise, 8 days post-exercise

    protein carbonyl concentration in vastus lateralis skeletal muscle

  5. Change in thiobarbituric acid reactive substances in red blood cells and serum

    Time frame: 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

  6. Change in thiobarbituric acid reactive substances in muscle

    Time frame: 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

  7. Change in oxidized glutathione in red blood cells and blood

    Time frame: 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

  8. Change in total antioxidant capacity in serum

    Time frame: one hour before exercise, 5 minutes post-exercise, 2 hours post-exercise, daily for 8 days post-exercise

  9. Change in oxidized glutathione in muscle

    Time frame: 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

  10. Change in catalase activity in red blood cells and serum

    Time frame: one hour before exercise, 5 minutes post-exercise, 2 hours post-exercise, daily for 8 days post-exercise

  11. Change in glutathione peroxidase activity in red blood cells

    Time frame: one hour before exercise, 5 minutes post-exercise, 2 hours post-exercise, daily for 8 days post-exercise

  12. Change in creatine kinase activity in plasma

    Time frame: one hour before exercise, 5 minutes post-exercise, 2 hours post-exercise, daily for 8 days post-exercise

  13. Change in C-reactive protein in plasma

    Time frame: one hour before exercise, 5 minutes post-exercise, 2 hours post-exercise, daily for 8 days post-exercise

  14. Change in macrophage infiltration in muscle

    Time frame: one hour before exercise, 2 hours post-exercise, 2 days post-exercise, 8 days post-exercise

  15. Change in white blood cell count in blood

    Time frame: one hour before exercise, 5 minutes post-exercise, 2 hours post-exercise, daily for 8 days post-exercise

  16. Change in neutrophil count in blood

    Time frame: one hour before exercise, 5 minutes post-exercise, 2 hours post-exercise, daily for 8 days post-exercise

  17. Change in fatty acid binding protein in plasma

    Time frame: one hour before exercise, 5 minutes post-exercise, 2 hours post-exercise, daily for 8 days post-exercise

  18. Change in cortisol concentration in blood

    Time frame: one hour before exercise, 5 minutes post-exercise, 2 hours post-exercise, daily for 8 days post-exercise

  19. Change in testosterone concentration in plasma

    Time frame: one hour before exercise, 5 minutes post-exercise, 2 hours post-exercise, daily for 8 days post-exercise

  20. Change in cytokine concentration in plasma

    Time frame: 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

  21. Change in adhesion molecule concentration in blood

    Time frame: 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

  22. Change in intracellular signalling proteins in muscle

    Time frame: 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.

  23. Change in myogenic determination factor (MyoD) protein levels in muscle

    Time frame: one hour before exercise, 2 hours post-exercise, 2 days post-exercise, 8 days post-exercise

    MyoD expression in vastus lateralis muscle

  24. Change in tumor necrosis factor α in muscle

    Time frame: 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

Secondary outcomes

  1. Change in muscle function of knee extensor and flexor muscle

    Time frame: 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

  2. Body composition

    Time frame: One day before exercise

    Assessment of percent (%) lean body mass.

  3. Maximal aerobic capacity

    Time frame: One day before exercise

    Assessment of maximal oxygen consumption, an indice of cardiovascular conditioning

  4. Change in profile of dietary intake

    Time frame: one hour before exercise, daily for 8 days post-exercise

    Assessment of dietary intake with emphasis on antioxidant element intake

  5. Change in side effect occurence

    Time frame: 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).

Sponsors and collaborators

Lead sponsor

Democritus University of Thrace

Other

Registry information

Official study title

Effects of NAC Supplementation on Skeletal Muscle Performance Following Aseptic Injury Induced by Exercise

Important dates

Study start
2010
Primary completion
2011
Study completion
2012
First posted
Jan 29, 2013
Registry last updated
Jan 29, 2013

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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