Hydrogen Sulfide Can Reduce Diabetic Cardiomyopathy Rats By Attenuate The Myocardial Apoptosis And Supprese The Oxidative Stress

Background and Objective:Cardiac failure is a main cause of the mortality of diabetic patients. In part this is due to a specific cardiomyopathy, called as diabetic cardiomyopathy(DC). Oxidative stress is widely considered to be one of the major elements underlying the pathogenesis of the DC. Mitochondria play a central role in controlling apoptosis, apoptotic factor release from mitochondria into the cytoplasm through the cascade reaction, thus starting the apoptosis. Bcl-2 family plays an important moderating role in this process. But molecular functional mechanisms of mitochondrial in the process of apoptosis remains to be further explored. With the in-depth study of the functional mechanism about mitochondrial in cell apoptosis, it will provide new ideas and methods for the treatment of DC, as well as providing new targets for the development of new drug. Hydrogen sulfide(H2S) is found to be the third gas signal molecule, which has the anti- Oxidative stress effects. This study aims to test whether H2 S could attenuate myocardial apoptosis through suppression of oxidative stress to alleviate diabetic cardiomyopathy. Methods:Adult male Sprague-Dawley(SD) rats for experiment were randomly divided into 5 groups: Control group, STZ group, C1 group, C2 group, H2 S group. Treated STZ group, C1 group and C2 group with STZ intraperitoneally(40 mg/kg) to establish DM models. 72 h after injection, we take the tail venous blood, the rats with blood glucose higher than 16.7 mmol/L were considered as successfully diabetes mellitus(DM) rats. Then treated C1 and C2 group with different concentrations of sodium hydrosulfide(NaHS) solution(30 mol/kg, 100 mol/kg) by intraperitoneal injection as a H2 S donor. After 8 weeks of experiment, The expressions of apoptosis related protein(Cleaved Caspase-3 and Bcl-2), H2 S enzyme(cystathionine-gamma-lyase, CSE, mercaptopyruvate sulfurtransferase, MPST) in heart tissue of every group were detected by Western blotting. We use HE staining method to detect myocardial pathological changes in each group. We adopt alkali hydrolysis method to detect the expression of hydroxyproline in heart tissue of diabetes rats. We applied electron microscope to observe cardiomyocytes. We measured GSH, 4-HNE, and MDA to assess oxidative damage by Elisa. We measured SOD by NBT. TUNEL-positive cells were identified in normal rat hearts. Results:1. The rat model of DM was established successfully. Blood glucose was measured after STZ injection for 72 h, the results showed that blood glucose increased significantly, and the blood glucose of each rat were higher than 16.7 mmol/L2. Hydrogen sulfide(H2S) has no effect on blood glucose concentration, body weight(BW), heart weight(HW). Hence blood glucose concentrations were increase in the DM group compared to NC group significantly. However, blood glucose concentrations in diabetic rats were not significantly affected by H2 S treatment compared with untreated diabetic rats. The BW and HW of diabetic rats were all lower than that of control animals after 8 weeks. The BW and HW of diabetic rats were not significantly affected by H2 S treatment, but exhibited an upward trend.3. H2 S can upregulate the expression of H2 S enzyme in DM rats. Results of western blotting show that the expression of H2 S enzyme, CSE and MPST, were decreased, while H2 S can increase the expression of CSE and MPST.4. H2 S inhibits myocardial fibrosis in STZ-induced diabetic rats. Hydrogen sulfide can improve the pathological changes of diabetic rat cardiomyocytes. We use HE staining method to detect myocardial pathological changes in each group. Tip H2 S can antagonize the pathological changes of diabetic rats. H2 S can reduce myocardial hydroxyproline expression in diabetes mellitus rat. We adopt alkali hydrolysis method to detect the expression of hydroxyproline in heart tissue of diabetes rats. The content of hydroxyproline in the myocardium from DM rats was obviously increased, and this was reversed by H2 S treatment.5. H2 S can delay the pathologic process of myocardial cells in diabetes mellitus rat. To determine whether H2 S can delay the pathologic process of myocardial cells in diabetes mellitus rat, we applied electron microscope to observe cardiomyocytes. The results indicated that the ratio for mitochondria edema of heart tissue in diabetes rats was significantly increased compared to control group, while administration of H2 S in diabetes rats prevented this phenomenon.6. H2 S can reduce oxidative damage caused by high plasma glucose concentration. We measured GSH, 4-HNE, SOD and MDA to assess oxidative damage in the myocardium and to determine whether H2 S can protects against oxidative stress damage. At 8 weeks later, the expression of SOD and GSH in DM showed a significant reduction, but there were increased by H2 S treatment. The content of MDA and 4-HNE in the myocardium from DM rats obviously increased, and there were reversed by H2 S treatment.7. H2 S can reduce myocardial cell apoptosis caused by high plasma glucose concentration. We used a Western blotting to detect the expression levels of Bcl-2 and caspase-3. The expression of Bcl-2 in DM showed a significant reduction, but this was increased by H2 S treatment. The content of caspase-3 in the myocardium from DM rats obviously increased, and this was reversed by H2 S treatment.TUNEL-positive cells were seldom identified in normal rat hearts. However TUNEL-positive cardiomyocytes were dramatically raised in diabetic rats. This is consistent with the result acquired from other animal studies. We find this apoptosis was reversed by H2 S treatment. Conclusion:1. Endogenous H2 S decrease production in DM rats’ heart tissue, while increase oxidative stress and cell apoptosis.2. H2 S can attenuate myocardial apoptosis through suppression of oxidative stress to alleviate diabetes myocardial damage.