Aim To investigate the effect of simvastatin ( Sim ) on endogenous antioxidant system after acute myocardial infarction ( AMI ) and its potential mecha-nisms. Methods The acute myocardial infarction ( AMI ) rat models were made by ligation left anterior descending of coronary artery. Then the successful models were randomly divided into myocardial infarc-tion group ( MI group) and simvastatin group ( Sim,20 mg·kg-1·d-1), another group without ligation left anterior descending of coronary artery served as sham group(Sham group). The Sim group was administered simvastatin by gavage for 7 days. MI group and Sham group received saline. Hemodynamic parameters, lipid levels, troponinI ( c-TnI ) and lactate dehydrogenase ( LDH) concentrations were examined after 7days, and the levels of superoxide dismutase ( SOD) and glutathi-one peroxidase ( GP) of myocardial antioxidant system were detected by ELISA. The expression of cardiac p-Akt and p-eNOS protein were detected by Western blot. Results Acute myocardial infarction significant-ly lowered cardiac hemodynamic parameters, increased serum c-TnI and LDH levels, lowered levels of SOD and GP, and lowered the expression of p-Akt and p-eNOS protein. However, Sim could effectively prevent the deterioration of cardiac function, reduce serum c-TnI and LDH levels, increase levels of SOD and GP, and increase p-Akt and p-eNOS protein expression. Conclusion Early using Sim can effectively improve heart function after acute myocardial infarction, acti-vate myocardial antioxidant system,and reduce myocar-dial necrosis, which may be related to increasing the expression of p-Akt and p-eNOS.

Aim To investigate the effect of metformin (Met) on connexin43(Cx43) expression in H9c2 cells cultured with high glucose and the relevant mecha-nisms.Methods Rat myocardial cells H9c2 were cul-tured with high glucose , then combined with 3μmol· L-1 and 5 μmol · L-1 of Met for 24 h respectively . The viability and toxicity of H9c2 cells were detected by MTT and LDH , respectively .The expression and distribution of Cx43 were detected by immunofluores-cence staining .The intracellular oxygen species reac-tive ( ROS) level was detected by fluorescencemicrosco-py.And the expression of Cx43, P-AMPK, AMPK and GAPDH was determined by Western blot .Results The viability of H9c2 cells was increased and the level of intracellular ROS was decreased in Met group , while there existed no significant difference in LDH release among groups.Met significantly increased the phos-phorylation of AMPK and the expression of Cx 43, and improved the distribution of Cx 43 also.Conclusion The beneficial effect of Met on cardiovascular system in diabetic patients may via up-regulating the expression of Cx43 and down-regulating of intracellular ROS through activation of AMPK .