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Objective: To investigate the effects of hydrogen sulfide (H2S) on H2O2-stimulated primary neonatal rat cardiomyocytes and related mechanism., Methods: Primary neonatal rat cardiomyocytes were treated with various concentrations of H2O2 (10, 100, 1000 µmol/L) for 24 h to establish the oxidative stress-induced cell injury model after 3 days' conventional culture. In addition, different concentrations of NaHS (1, 10, 100 µmol/L) were added to cardiomyocytes in the absence and presence of 100 µmol/L H2O2 for 24 h. The viability of cardiomyocytes was measured by MTT assay. The SOD vitality was measured by xanthine oxidase method and MDA content was determined by thiobarbituric acid colorimetric method. LDH activity was measured by chemical colorimetric method. The percentage of apoptotic cells was assessed by flow cytometry (FCM). The mitochondrial membrane potential (MMP) was analyzed by rhodamine 123 (Rh123) staining and photofluorography. The level of reactive oxygen species (ROS) in cardiomyocytes was measured by DCFH-DA staining and photofluorography., Results: Cell viability and SOD vitality were significantly reduced while MDA content and LDH activity were significantly increased with increasing H2O2 concentrations. These effects could be partly reduced by cotreatment with H2O2 in a concentration-dependent manner (all P < 0.05). Compared with control group, the DCF fluorescence intensity significantly increased in the 100 µmol/L H2O2 group (P = 0.003), which could be attenuated by NaHS in a dose-dependent manner. Compared with control group, the MMP significantly decreased in the 100 µmol/L H2O2 group (P = 0.000), which could be partly reversed by cotreatment with NaHS in a dose-dependent manner. Moreover, H2O2 treatment also significantly reduced 100 µmol/L H2O2 induced apoptosis in a dose-dependent manner., Conclusion: H2S protects primary neonatal rat cardiomyocytes against H2O2-induced oxidative stress injury through inhibition of H2O2 induced overproduction of ROS, dissipation of MMP and apoptosis.

Objective: To investigate the effects of simvastatin (SIM) on homocysteine (HCY)-induced endothelial dysfunction and inflammatory response., Methods: Human umbilical vein endothelial cells (HUVECs) were isolated from the umbilical cords from healthy lying-in women and cultured and added with HCY of the concentrations of 0.1, 0.25, 0.5, and 1 mmol/L respectively, or HCY 0.25 mmol/L + SIM of the concentrations of 1, 10 and 20 micromol/L respectively for 1 hour. ELISA was used to detect the cell viability with MTT method. Western blotting was used to examine the protein expression of the cell inflammatory factors, tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, macrophage chemoattractant protein (MCP)-1, and intercellular adhesion molecule (ICAM)-1, ELISA was used to detect the contents of the cell inflammatory factors., Results: HCY of different doses inhibited the viability of HUVECs dose-dependently (all P < 0. 01). The survival rates of the HCY-induced HUVECs pretreatment by SIM of the concentrations of 1, 10 and 20 micromol/L for 1 hour were 1.72 +/- 0.03 times, 2.54 +/- 0.09 times, and 3.14 +/- 0.11 times respectively that of the control group (all P < 0. 01). HCY of different concentration of 0.25 mmol/L increased the protein expression of TNF-alpha, IL-6, MCP-1, and ICAM-1 significantly; however, the expression levels of TNF-alpha, IL-6, MCP-1, and ICAM-1 of the 0.25 mmol/L HCY-treated HUVECs that were pretreated by SIM of the concentration of 10 micromol/L for 1 hour were, 0.23 +/- 0.05, 0.14 +/- 0.03, 0.13 +/- 0.04, and 0.21 +/- 0.07 respectively, not significantly different from those at the time of 0 hour (all P > 0.05)., Conclusion: Simvastatin inhibits the homocysteine-induced endothelial impairment and inflammatory response.