The Effects And Mechanisms Of Simvastatin On High Glucose-induced Injury In The Neonatal Rat Cardiomyocytes

Objectives:1,To investigate the effects of high concentration of glucose on the neonatal rat cardiomyocytes and explore the potential molecular mechanisms;2,To observe the protective effects of simvastatin on cardiomyocytes injury induced by high concentration of glucose in the neonatal rats and explore the potential molecular mechanisms.Methods:Ventricular myocytes were isolated from hearts of the neonatal SD rats by enzymatic digestion and anchorage velocity-dependent separation method for primary culture. Cardiomyocytes were randomly divided into seven groups: control group, high glucose group(GS), different concentration simvastatin (10-7mol/L,10-6mol/L,10-5 mol/L)+high glucose group, high glucose+0.2mmol/Lmevalonic acid(MVA) group, 10-5mol/ Lsimvastatin+high glucose+0.2mmol/LMVA group. After 72 hours'treatment, the cells of each group were collected and the following measures were carried out: cadiocyte activity was detected by MTT chromatometry; Activities of LDH and SOD, the contents of MDA,NO and GSH,the expression of Caspase-3 and concentration of intracellular ROS were measured according to their manufacturers'instructions respectively;The expression of NADPH oxidase subunits p22phox,p47phox mRNA was detected by RT-PCR;And the expression of p38MAPK protein was determined by Western blot analysis.Results:1,Compared with control group, the activity of cadiomyocyte was significantly lower in high glucose group. The activity of LDH,the content of MDA and the intracellular ROS generation in the GS group showed significant increase,and there was a decrease in the GSH,NO content and the activities of SOD compared to control group. Activation of NADPH oxidase subunit p22phox,p47phox and expression of p38MAPK respectively raised to 2.26-,2.08-,2.6-fold in the GS group. Besides the expression of Caspase-3 was obviously higher in the GS group.2,Above-mentioned indexes were significantly improved by simvastatin treatment in a dose-dependent manner in simvastatin+GS groups. Activities of cardiomyocytes were obviously up-regulated; activities of LDH, the content of MDA and intracellular ROS generation were down-regulated; And the content of GSH,NO and the activities of SOD was up-regulated compared to GS group in 3 different GS+Simvastatin groups. In addition, Simvastatin not only inhibited high glucose-induced activation of NADPH oxidase and expression of p38MAPK but also reduced expression of Caspase-3. Moreover, there were significant differences among 3 different simvastatin groups in the following indexes including activities of cardiomyocytes, MDA content, SOD activity, concentration of intracellular ROS, the expression of NADPH oxidase subunits mRNA and p38MAPK protein of cardiomyocytes as well as expression of Caspase-3. There was no significant difference between 10-5MSimvastatin+GS group and control group.3,Mevalonate could reverse these effects of simvastatin (P>0.05).Conclusions1,High concentration of glucose could induce oxidative stress of cardiomyocytes and lead to their injury.2,High glucose-induced injury of cardiomyocytes was alleviated by Simvastatin which is related to suppression of cellular oxidative stress damage.3,Mevalonate could reverse the protective effects of simvastatin.4,Simvastatin significantly protects the cardiomyocytes against high glucose inducing oxidative stress damage, probably through downregulation of NADPH oxidase-ROS- p38MAPK signaling pathway and suppression of MVA pathway.