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Intramuscular adaptations to eccentric exercise and antioxidant supplementation.
Amino Acids. 2010 Jun; 39(1):219-32.AA

Abstract

Prophylactic supplementation of N-acetyl-cysteine (NAC) and epigallocatechin gallate (EGCG) was studied for physiological and cellular changes in skeletal muscle after eccentric muscle contractions. Thirty healthy, active males (20.0 +/- 1.8 years, 160 +/- 7.1 cm, 76.1 +/- 17.0 kg) ingested for 14 days either 1,800 mg of NAC, 1,800 mg of EGCG, or 1,000 mg of fiber (glucomannan) placebo (PLC) in a double blind, prophylactic fashion. Subjects completed one eccentric exercise bout (100 repetitions at 30 degrees /s) using the dominant knee extensors. Strength and soreness were assessed, and blood and muscle samples obtained before and 6, 24, 48, and 72 h with no muscle sample being collected at 72 h. Separate mixed factorial repeated measures ANOVA (P < 0.05) were used for all statistical analysis. All groups experienced significantly reduced peak torque production after 6 and 24 h, increased soreness at all time points from baseline [with even greater soreness levels 24 h after exercise in PLC when compared to EGCG and NAC (P < 0.05)], increased lactate dehydrogenase at 6 h, and increased creatine kinase 6, 24 and 48 h after exercise. No significant group x time interaction effects were found for serum cortisol, neutrophil counts, and the neutrophil:lymphocyte ratio; although, all values experienced significant changes 6 h after exercise (P < 0.05), but at no other time points. At 48 h after the exercise bout the Neu:Lym ratio in EGCG was significantly less than NAC (P < 0.05), whereas there was a trend (P = 0.08) for the EGCG values to be less when compared to PLC at this time point. Markers of intramuscular mitochondrial and cytosolic apoptosis were assessed (e.g., bax, bcl-2, cytochrome C, caspase-3 content/enzyme activity, and total DNA content). Significant increases (P < 0.05) in muscle levels of bax and bcl-2 were observed in all groups with no significant differences between groups, whereas no changes (P > 0.05) were reported for cytochrome C, caspase-3 content, caspase-3 enzyme activity, and total DNA. Caspase-3 enzyme activity was significantly greater in all groups 48 h after exercise when compared to baseline (P < 0.05) and 6 h (P < 0.05) after exercise. An eccentric bout of muscle contractions appears to significantly increase muscle damage, markers of mitochondrial apoptosis, apoptotic enzyme activity, and whole-blood cell markers of inflammation with no changes in oxidative stress. While soreness ratings were blunted in the two supplementation groups 24 h after exercise when compared to PLC values, more research is needed to determine the potential impact of EGCG and NAC supplementation on changes related to oxidative stress, apoptosis, and eccentric exercise.

Authors+Show Affiliations

Health and Exercise Science Department, University of Oklahoma, 1401 Asp Avenue, Norman, OK 73019, USA.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

19967420

Citation

Kerksick, Chad M., et al. "Intramuscular Adaptations to Eccentric Exercise and Antioxidant Supplementation." Amino Acids, vol. 39, no. 1, 2010, pp. 219-32.
Kerksick CM, Kreider RB, Willoughby DS. Intramuscular adaptations to eccentric exercise and antioxidant supplementation. Amino Acids. 2010;39(1):219-32.
Kerksick, C. M., Kreider, R. B., & Willoughby, D. S. (2010). Intramuscular adaptations to eccentric exercise and antioxidant supplementation. Amino Acids, 39(1), 219-32. https://doi.org/10.1007/s00726-009-0432-7
Kerksick CM, Kreider RB, Willoughby DS. Intramuscular Adaptations to Eccentric Exercise and Antioxidant Supplementation. Amino Acids. 2010;39(1):219-32. PubMed PMID: 19967420.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Intramuscular adaptations to eccentric exercise and antioxidant supplementation. AU - Kerksick,Chad M, AU - Kreider,Richard B, AU - Willoughby,Darryn S, Y1 - 2009/12/05/ PY - 2009/08/05/received PY - 2009/11/17/accepted PY - 2009/12/8/entrez PY - 2009/12/8/pubmed PY - 2010/9/15/medline SP - 219 EP - 32 JF - Amino acids JO - Amino Acids VL - 39 IS - 1 N2 - Prophylactic supplementation of N-acetyl-cysteine (NAC) and epigallocatechin gallate (EGCG) was studied for physiological and cellular changes in skeletal muscle after eccentric muscle contractions. Thirty healthy, active males (20.0 +/- 1.8 years, 160 +/- 7.1 cm, 76.1 +/- 17.0 kg) ingested for 14 days either 1,800 mg of NAC, 1,800 mg of EGCG, or 1,000 mg of fiber (glucomannan) placebo (PLC) in a double blind, prophylactic fashion. Subjects completed one eccentric exercise bout (100 repetitions at 30 degrees /s) using the dominant knee extensors. Strength and soreness were assessed, and blood and muscle samples obtained before and 6, 24, 48, and 72 h with no muscle sample being collected at 72 h. Separate mixed factorial repeated measures ANOVA (P < 0.05) were used for all statistical analysis. All groups experienced significantly reduced peak torque production after 6 and 24 h, increased soreness at all time points from baseline [with even greater soreness levels 24 h after exercise in PLC when compared to EGCG and NAC (P < 0.05)], increased lactate dehydrogenase at 6 h, and increased creatine kinase 6, 24 and 48 h after exercise. No significant group x time interaction effects were found for serum cortisol, neutrophil counts, and the neutrophil:lymphocyte ratio; although, all values experienced significant changes 6 h after exercise (P < 0.05), but at no other time points. At 48 h after the exercise bout the Neu:Lym ratio in EGCG was significantly less than NAC (P < 0.05), whereas there was a trend (P = 0.08) for the EGCG values to be less when compared to PLC at this time point. Markers of intramuscular mitochondrial and cytosolic apoptosis were assessed (e.g., bax, bcl-2, cytochrome C, caspase-3 content/enzyme activity, and total DNA content). Significant increases (P < 0.05) in muscle levels of bax and bcl-2 were observed in all groups with no significant differences between groups, whereas no changes (P > 0.05) were reported for cytochrome C, caspase-3 content, caspase-3 enzyme activity, and total DNA. Caspase-3 enzyme activity was significantly greater in all groups 48 h after exercise when compared to baseline (P < 0.05) and 6 h (P < 0.05) after exercise. An eccentric bout of muscle contractions appears to significantly increase muscle damage, markers of mitochondrial apoptosis, apoptotic enzyme activity, and whole-blood cell markers of inflammation with no changes in oxidative stress. While soreness ratings were blunted in the two supplementation groups 24 h after exercise when compared to PLC values, more research is needed to determine the potential impact of EGCG and NAC supplementation on changes related to oxidative stress, apoptosis, and eccentric exercise. SN - 1438-2199 UR - https://wwww.unboundmedicine.com/medline/citation/19967420/Intramuscular_adaptations_to_eccentric_exercise_and_antioxidant_supplementation_ L2 - https://dx.doi.org/10.1007/s00726-009-0432-7 DB - PRIME DP - Unbound Medicine ER -