Accession Number : ADA580314


Title :   The Effect of Smoking on Muscle Adaptation to Exercise Stress


Descriptive Note : Final rept. 23 Nov 2009-30 Nov 2011


Corporate Author : MASSACHUSETTS UNIV AMHERST


Personal Author(s) : Clarkson, Priscilla


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a580314.pdf


Report Date : Dec 2011


Pagination or Media Count : 116


Abstract : Cigarette smoking is prevalent in the military and is associated with increased risk for musculoskeletal injury. This study investigated differences in functional strength and molecular alterations in blood and muscle samples between smokers and nonsmokers in response to a muscle-damaging exercise. 10 smokers and 10 non-smokers performed a maximal eccentric exercise of the non-dominant knee extensors. Isometric and isokinetic strength were measured pre- and 5min, 1, 4, and 9d post-exercise. Blood was collected pre- and 20h post-exercise, and biopsy samples were obtained from control and exercise legs at 48h post-exercise. Smokers had greater loss in flexion strength at 4d post-exercise for isometric strength (p0.05), likely due to the effect of the biopsy and slower healing rate in the smokers. Using PCR array, we found that non-smokers increased gene expression (mRNA) while smokers had a down regulation of expression in most of 44 genes studied. Significant changes in mRNA involved several key functions involved in muscle regeneration including maintenance of structure, nitric oxide signaling, angiogenesis, myogenesis, and inflammation, generally showing an attenuated response to exercise in the smokers. For example, regarding inflammation, in smokers there was an attenuated exercise-induced increase in CHUK (IKK!) mRNA, an upstream mediator of nuclear factor-kappa B (NFB ), a key player in muscle inflammation. Further testing showed that the activity of the canonical and non-canonical NFB pathways was altered in non-smokers but not in smokers. Western blotting yielded significantly higher phosphorylated and total ERK1/2 (involved in several pathways important to muscle regeneration) in smokers at baseline. Taken together, these data suggest that smokers not only have baseline differences in key components of muscle function but also show attenuated responses to eccentric exercise, especially in pathways involved in inflammation and regeneration.


Descriptors :   *EXERCISE(PHYSIOLOGY) , *MUSCLES , *MUSCULOSKELETAL SYSTEM , *TOBACCO SMOKING , BIOPSY , BLOOD , CONTROL , EXTENSOMETERS , GENES , HEALING , INFLAMMATION , KINETICS , KNEE(ANATOMY) , MOLECULES , RESPONSE , RISK , STRENGTH(PHYSIOLOGY) , WOUNDS AND INJURIES


Subject Categories : Anatomy and Physiology
      Medicine and Medical Research
      Stress Physiology


Distribution Statement : APPROVED FOR PUBLIC RELEASE