Effects of heat shock protein 70 on myocardial cell apoptosis and expression of nitric oxide and nitric oxide synthnase in isolated rat heart

Abstract

Objective To investigate the effects of heat shock protein 70 (HSP70) on myocardial cell apoptosis,expression of nitric oxide(NO)and nitric oxide synthnase(NOS).Methods Eighteen Wistar rats were randomly divided into two groups.In experiment group (E),norepinephrine was injected intraperitioneally,and 24 h later isolated hearts were stored in 4℃ for 3 h with Histidine-trytophan-ketoglurate(HTK),and then perfused with Krebs-Henseleit solution for 2 h by Langendorff model. In control group(C),normal saline(0.5 ml)was injected intraperitioneally,and 24 h later isolated hearts were stored in 4℃ for 3 h with HTK solutions.and then perfused with Krebs-Henseleit solution for 2 h by Langendorff model .The myocardial HSP70 content,myocardial apoptosis index and the expression of NO and NOS were detected.Results HSP70,NO and NOS contents in E group were higher than in C group.The myocardial apoptosis index in E group was lower than in C group.The HSP70 content had a positive correlation with NO (r=0.887,P<0.01) and NOS(r=0.953,P<0.01)contents,and a negative correlation with myocardial apoptosis index (r=-0.946,P<0.01).Conclusion HSP70 can obviously decrease myocardial cell apoptosis and increase the expression of NO,and NOS in isolated rat hearts. Key words: Heat-shock protein 70; Apoptosis; Nitric oxide; Nitric-oxide synthase; Myocardium