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 (H 2 S) is endogenously produced in mammalian tissues and participates in a number of physiological and pathophysiological processes. We aimed to verify whether H 2 S could be endogenously generated and released by rat skeletal muscle, and determine the biological effects of H 2 S in rat skeletal muscle. Methods The study was divided into two parts: detection of endogenous H 2 S generation and release in rat skeletal muscle and determination of antioxidative activity of skeletal muscle-derived H 2 S. H 2 S content and production in tissues were detected by sensitive sulfur electrode method. The expressions of H 2 S 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 H 2 S could be endogenously generated and released by skeletal muscle of Sprague-Dawley rats (H 2 S content: (2.06±0.43) nmol/mg; H 2 S production: (0.17±0.06) nmol·min -1 ·mg -1 ). Gene and protein expressions of the three H 2 S producing enzymes were detected in skeletal muscle, as well as the liver and kidney. Endogenous H 2 S content and production were decreased in skeletal muscles of rats with I-R skeletal muscle injury ( P <0.05). Furthermore, H 2 S 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). Conclusion H 2 S generation pathway exists in rat skeletal muscle and it acts as an antioxidant in skeletal muscle.