Cardioprotective effect of H2S and glutathione synthesis modulation is mediated by inhibition mitochondrial permeability transition pore opening

Abstract

Hydrogen sulfide (H2S) was recently classified as the third gaseous transmitter produces by two cytosolic cystathionine γ-lyase (CSE) and cystathionine β-synthase, and one mitochondrial enzyme – 3-mercaptopyruvate sulfurtransferase. It was clearly shown that H2S protects against cardiac ischemia/reperfusion (I/R) injury in a wide range of exogenously applied doses of H2S donors. Cell damage within I/R injury is caused by extensive reactive oxygen species (ROS) mainly produced by mitochondria. ROS fleshes are associated with massive opening of mitochondrial permeability transition (MPT) pores and contribute to deterioration of heart function. However, it may be prevented in case of pharmacological inhibition of MPT pores opening. Mixture of mitochondrial metabolites released through the opened MPT pores can be detected in situ as increased optical density of outflow solutions at a wavelength of 245-250 nm and was called mitochondrial factor (MF). One of the most powerful antioxidant agents that preserve redox status in tissues is tripeptide glutathione. It forms in two ATP-depended reactions and exists in two forms reduced and oxidized one. Glutathione and H2S have a common precursor – amino acid L-cysteine. In this study, we used Langendorff isolated rat heart model to investigate the effect of H2S and glutathione synthesis modulation on MPT pores opening in I/R injury. Rats were pretreated intraperitoneally with D,L-propargylglycine (11,3 mg/kg), an inhibitor of H2S-producing enzyme CSE, L-cysteine (121 mg/kg) and buthionine sulfoximine (BSO, 22,2 mg/kg) an inhibitor of first step of glutathione synthesis. Cardiac function, oxygen metabolism and MPT pores opening in situ were measured. We clearly showed that treatment with PAG and L-cysteine provided pharmacological precondition and exerted cardioprotective effect inhibiting MPT pores opening as greatly decreased MF release from isolated heart. Pretreatment with BSO abolished cardioprotective effect of PAG+L-cysteine combination. Absorbance spectra in L-cysteine pretreated group did not differ from the control. Thus, we demonstrate that PAG+L-cysteine induced cardioprotection mediated via inhibition of MPT pores opening.