Role Of Glycine Receptor In Anoxia/reoxygenation Injury In Cardiomyocytes

ObjectivesWe have demonstrated that glycine receptor exists in rat cardiomyocytes and glycine has a protective effect against anoxia/reoxygenation injury in the cardiomyocytes, but the mechanism is still unclear. The aim of this study was to investigate the role of glycine receptor action in anoxia/reoxygenation injury in cardiomyocytes with respect to oxygen free radical metabolism, apoptosis and intracellar calcium oveload.MethodsThe neonatal rat cardiomyocytes were cultured and exposed to anoxia and reoxygenation (A/R).The cultured cardiomyocytes were divided into 9 groups and treated as follows: (1)contorl (2)glycine (3)strychine (4)free chlorine medium (5)A/R (6)glycine+A/R (7)strychine+A/R (8)glycine+strychine+A/R, and free chlorine medium+A/R group. The superoxide dismutase(SOD) activity, the contents of malondialdehyde(MDA) and nitric oxide(NO) in the cardiomyocytes were determined.In addition, the cardiomyocyte survival rate was examined, the intracellular free calcium concentration was detected by using Flou-3/AM staining, and the apoptotic rate was also determined by using annexin V-FITC/PI staining in Flow cytometry.Results(1)SOD activity, NO content in cardiomyocytes were less, but MDA content was higher in A/R group than those in control. Pretreatment with glycine inhibited the above changes caused by A/R, which was reversed by strychnine treatment and in the free chloride medium.(2) A/R resulted in increase in intracellular free calcium concentration and apoptotic rate in cardiomyocytes, which was inhabited by pretreatment with glycine.