title: Hydrogen sulfide is endogenously generated in rat skeletal muscle and exerts a protective effect against oxidative stress.
abstract: BACKGROUND
  Skeletal muscle has recently been recognized as an endocrine organ that can express, synthesize and secrete a variety of bioactive molecules which exert significant regulatory effects. Hydrogen sulfide (H2S) is endogenously produced in mammalian tissues and participates in a number of physiological and pathophysiological processes. We aimed to verify whether H2S could be endogenously generated and released by rat skeletal muscle, and determine the biological effects of H2S in rat skeletal muscle.
  
  
  METHODS
  The study was divided into two parts: detection of endogenous H2S generation and release in rat skeletal muscle and determination of antioxidative activity of skeletal muscle-derived H2S. H2S content and production in tissues were detected by sensitive sulfur electrode method. The expressions of H2S producing enzymes cystathionine β-synthase, cystathionine γ-lyase and mercaptopyruvate sulfurtransferase were detected by real-time PCR and western blotting and their tissue distributions were observed by immunohistochemical and immunofluorescent analysis. Rat skeletal muscular ischemia-reperfusion (I-R) injury model was created and evaluated by histological analysis under microscope. The malondialdehyde (MDA) contents, hydrogen peroxide levels, superoxide anion and superoxide dismutase (SOD) activities were detected using spectrophotometer.
  
  
  RESULTS
  H2S could be endogenously generated and released by skeletal muscle of Sprague-Dawley rats (H2S content: (2.06 ± 0.43) nmol/mg; H2S production: (0.17 ± 0.06) nmol×min(-1)×mg(-1)). Gene and protein expressions of the three H2S producing enzymes were detected in skeletal muscle, as well as the liver and kidney. Endogenous H2S content and production were decreased in skeletal muscles of rats with I-R skeletal muscle injury (P < 0.05). Furthermore, H2S significantly protected rat skeletal muscle against I-R injury and resulted in decreased MDA content, reduced hydrogen peroxide and superoxide anion levels, but increased SOD activity and protein expression in skeletal muscles (all P < 0.01).
  
  
  CONCLUSIONS
  H2S generation pathway exists in rat skeletal muscle and it acts as an antioxidant in skeletal muscle.
authors.affiliation: Department of Clinical Medicine, Capital Medical University, Beijing 100069, China.
authors.forename: Jian-tong
authors.initials: JT
authors.lastname: DU
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.forename: Jin-yan
authors.initials: JY
authors.lastname: Yang
authors.forename: Chao-shu
authors.initials: CS
authors.lastname: Tang
authors.forename: Qi
authors.initials: Q
authors.lastname: Li
authors.forename: Hong-fang
authors.initials: HF
authors.lastname: Jin
mesh_terms: D000818:Animals; D015153:Blotting, Western; D006861:Hydrogen Peroxide / Q000378:metabolism; D006862:Hydrogen Sulfide / Q000378:metabolism*; D007150:Immunohistochemistry; D008297:Male; D008315:Malondialdehyde / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism*; D018384:Oxidative Stress / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013482:Superoxide Dismutase / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism
chemical_list: D013481:Superoxides; D008315:Malondialdehyde; D006861:Hydrogen Peroxide; D013482:Superoxide Dismutase; D006862:Hydrogen Sulfide