title: Effect of N-acetylcysteine on markers of skeletal muscle injury after fatiguing contractile activity.
abstract: The effects of N-Acetylcysteine (NAC), an unspecific antioxidant, on fatiguing contractile activity-induced injury were investigated. Twenty-four male Wistar rats were randomly assigned to two groups. The placebo group (N=12) received one injection of phosphate buffer (PBS) 1 h prior to contractile activity induced by electrical stimulation. The NAC group (NAC; N=12) received electrical stimulation for the same time period and NAC (500 mg/kg, i.p.) dissolved in PBS 1 h prior to electrical stimulation. The contralateral hindlimb was used as a control, except in the analysis of plasma enzyme activities, when a control group (rats placebo group not electrically stimulated and not treated) was included. The following parameters were measured: tetanic force, muscle fatigue, plasma activities of creatine kinase (CK) and lactate dehydrogenase (LDH), changes in muscle vascular permeability using Evans blue dye (EBD), muscle content of reactive oxygen species (ROS) and thiobarbituric acid-reactive substances (TBARS) and myeloperoxidase (MPO) activity. Muscle fatigue was delayed and tetanic force was preserved in NAC-treated rats. NAC treatment decreased plasma CK and LDH activities. The content of muscle-derived ROS, TBARS, EBD and MPO activity in both gastrocnemius and soleus muscles were also decreased by NAC pre-treatment. Thus, NAC has a protective effect against injury induced by fatiguing contractile activity in skeletal muscle.
authors.affiliation: Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil. chjpinheiro@gmail.com
authors.forename: C H J
authors.initials: CH
authors.lastname: Pinheiro
authors.forename: K F
authors.initials: KF
authors.lastname: Vitzel
authors.forename: R
authors.initials: R
authors.lastname: Curi
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology*; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D002199:Capillary Permeability / Q000187:drug effects*; D003402:Creatine Kinase / Q000097:blood / Q000187:drug effects; D004558:Electric Stimulation; D005070:Evans Blue / Q000493:pharmacokinetics*; D007770:L-Lactate Dehydrogenase / Q000097:blood / Q000187:drug effects; D008297:Male; D009119:Muscle Contraction; D018763:Muscle Fatigue / Q000187:drug effects; D053580:Muscle Strength / Q000187:drug effects; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000293:injuries / Q000378:metabolism*; D009195:Peroxidase / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000378:metabolism; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism
chemical_list: D000975:Antioxidants; D017382:Reactive Oxygen Species; D017392:Thiobarbituric Acid Reactive Substances; D005070:Evans Blue; D007770:L-Lactate Dehydrogenase; D009195:Peroxidase; D003402:Creatine Kinase; D000111:Acetylcysteine