The protective role of hydrogen sulfide in myocardial ischemia-reperfusion-induced injury in diabetic rats

BackgroundHydrogen sulfide (H2S) displays anti-inflammatory and cytoprotective activities to attenuate myocardial ischemia-reperfusion (MIR)-induced injury, but its role in MIR in diabetics is not known. This study was undertaken to investigate whether H2S plays a protective role in MIR in diabetic rats.MethodsDiabetes was induced by streptozocin in Wistar rats, which were subjected to myocardial ischemia by blocking the left circumflex artery for 30 min, followed by 2 h reperfusion. dl-propargylglycine (PAG) and sodium hydrosulfide (NaHS) were administered to the rats to investigate their effects on severity of MIR-induced injury.ResultsDiabetic rats had smaller myocardial infarct sizes and higher serum levels of H2S (both P < 0.05) than non-diabetics when they underwent MIR. MIR significantly increased the serum level of H2S (49.5 ± 7.1 μM), H2S-synthesizing activity (7.4 ± 1.6 nmol/mg) and the myocardial infarct size (44.0 ± 7.2%), compared with sham-operated diabetic rats (21.7 ± 2.1 μM, 0.15 ± 0.4 nmol/mg and 1.2 ± 0.4%, respectively). Administration of NaHS increased the H2S level (65.8 ± 6.9 μM) and had little effect on H2S production activity (6.5 ± 2.2 nmol/mg), while PAG reduced both the H2S level (29.2 ± 5.0 μM) and H2S-synthesizing activity (2.2 ± 1.8 nmol/mg). NaHS significantly reduced the myocardial infarct size (31.2 ± 4.7%), inhibited the production of lipid peroxidation, MPO activity, and cell apoptosis, and downregulated expression of caspase-3, Fas, FasL, and TNF-α, which had been elevated by MIR, while PAG further increased the myocardial infarct size (58.3 ± 5.9%), and displayed opposite effects.ConclusionsThe study indicates that H2S may play a protective role in MIR-induced myocardial injury in diabetics by its anti-apoptotic, anti-oxidative and anti-inflammatory activities.