Effect of modulation of hydrogen sulfur and glutathione synthesis on oxidative and nitrosative metabolism under myocardial ischemia-reperfusion

Abstract

Redox balance maintaining is a prerequisite for normal cardiomyocytes metabolism. Reperfusion injury of the heart is characterized by an explosive increase in ROS generation, cell membranes damage, dysfunction of proteins, the development of muscle contracture etc. It was shown that the hydrogen sulfide (H2S) and the precursor of its synthesis the amino acid L-cysteine provided cardioprotective effect against ischemiareperfusion, In addition, L-cysteine is one of amino acids that form an antioxidant glutathione (GSH). The aim of our work was to investigate the effect of GSH and H2S synthesis modulation on the oxidative and nitrosative stress in cardiac tissues under conditions of ischemia-reperfusion. The H2S synthesis inhibitor propargylglycine (PAG), the GSH synthesis inhibitor butionine sulfoxime (BSO) and L-cysteine were administered intraperitoneally. Next, ischemia-reperfusion of the Langendorff isolated rat heart was performed. In the tissues of rat's hearts, before and after ischemia, we determined the rate of ROS generation, content of POL products, the activity of NO synthesizing enzymes. Results of our study showed that pretreatment with PAG + L-cysteine combination prevented heart function disturbances, ROS formation, increased low molecular weight nitrosothiols content, preserved the activity of constitutive NOS and inhibited the activity of inducible NOS in the pre-ischemic period as well as in the period of reperfusion. Pretreatment with BSO in PAG + L-cysteine group significantly reduced the effectiveness of the combination and abolished cardioprotective effect. Generation of superoxide and hydroxyl anions was increased, activity of inducible NO-synthase was 3.5-fold increased comparing with PAG + L-cysteine pretreated group. Pretreatment with PAG + L-cysteine combination inhibited the formation of ROS and preserved the activity of constitutive NOS, thus providing stable production of NO. Pretreatment with BSO completely abolished an antioxidant effect of PAG + L-cysteine decreasing bioavailability of glutathione.