The Role Of Oxidative Stress And Endoplasmic Reticulum Stress On Apoptosis In Neonatal Rat Cadiocyte Induced By High Glucose

ObjectiveUsing cultured cardiomyocytes of neonatal Sprague-Dawley rats as a model,To explore the effects of the different glucose concentration and the relationship between oxidative stree and endoplasmic reticulum stress by reactive oxygen species on high glucose-induced apoptosis in neonatal rat cardiomyocytes. This study demonstrated that Oxidative stree and the endoplasmic reticulum stress contributes to cardiomyocyte apoptosis.Methods1. Neonatal Sprague-Dawley rats'cardiac myocytes were isolated by co-digestion of dispaseâ…¡and collagenaseâ…¡, and then cultured in vitro. The cardiac myocytes of rat were devided into six groups as below: group A (5.6 mmol/L); group B (16.7mmol/L); group C (25mmol/L); group D (33.3mmol/L); groupE (50mmol/L).Aapoptosis of neonatal rat cardiac myocytes was detected by flow cytometry and MTT.Observe the effects of different concentrations of glucose on cell apoptosis.2. Using cadiocyte of induced by high glucose as a model, groups were divided into: control group (glucose: 5.6 mmol/L); high glucose group (glucose: 25mmol/L); the antioxidant group. Oxidative stress was evaluated by detecting levels of ROS and SOD in the supernatant of culture media. The mRNA expression of GRP78 and CHOP and Caspase-12 was used to determine by RT-PCR and immunocytochemical method in the cardiac myocytes of rat. Results1. Compared with group A, group B had no significant cardiomyocyte apoptosis and cytoactive.The apoptosis rate and cytoactive of group C increased (P<0.05), but group D and E had significant insreased (P<0.01), Cardiomyocytes cultured in different glucose level showed an increased the apoptosis rate and decreased cytoactive consistent with the increased glucose levels.2. The study showed significant increase of ROS levels (P<0.01) and decrease of SOD activity (P<0.01) in the high glucose group compared with the control group. However in the antioxidant group ROS levels decreased significantly (P<0.01)and SOD activity increased (P<0.05) compared with the high-glucose group. Simultaneously the higher expression of GRP78,CHOP and Caspase-12 mRNA compared with the control group(P<0.01). The antioxidant(NAC) could partly reverse these changes induced by high glucose level(P<0.01).Conclusion1.High glucose can induce in vitro neonatal rat cardiomyocyte apoptosis.2.The antioxidant (NAC) may inhibit high glucose-induced apoptosis via blocking oxidatie stress and endoplasmic reticulum stress pathway by decrease ROS in the process of myocardial cell apoptosis.3.The ROS by can target the endoplasmic reticulum stress of oxidative stress release,they are joint participation in the process of myocardial cell apoptosis by induced of high glucose.