Effect of cerium oxide nanoparticles preconditioning on ischemia-reperfusion injury of rat cardiomyocyte apoptosis

Objective To investigate the effect of cerium oxide (CeO2) nanoparticles on cardiomyocyte apoptosis,and expression of B lymphocytes/leukemia-2 (bcl-2),bcl-2 associated X protein (bax) and Caspase-3 mRNA following myocardial ischemia-reperfusion injury (MIRI) in rats.Methods Forty health male Sprague-Dawley rats were randomly divided into five groups:sham group,I/R group,I/R + CeO2 preconditioning groups with three diverse nano size (1-10,10-25,50 nm).The MIRI model of rats in vivo was established successfully.Hematoxylin-eosin staining (HE) method was used to identify the pathologic changes of myocardial tissue.The apoptotic cardiomyocytes were detected by in situ TdT-media-ted dUTP nick end labeling (TUNEL) method,and the mRNA expression levels of bcl-2,bax and Caspase-3 were detected by using reverse transcription polymerase chain reaction (RT-PCR).Results Compared with the sham group,myocardial ischemia and myocardial infarction areas were significantly increased in I/R group and I/R + CeO2 preconditioning groups.The apoptosis rate of cardiomyocytes in I/R + CeO2 (10-25 nm) group was significantly decreased (P ＜ 0.01 or P ＜ 0.05) as compared other groups except the Sham group.Compared with the I/R group,the mRNA expression level of bcl-2 was increased (P ＜0.01) and that of bax and Caspase-3 was significantly decreased (P ＜ 0.01) in the I/R + CeO2 precondi-tioning groups.Conclusion CeO2 nanoparticles can inhibit the apoptosis of myocardium induced by MIRI,probably through the mechanisms of up-regulating the expression of bcl-2 and down-regulating the expression of bax and Caspase-3.The 10-25 nm CeO2 nanoparticles show the most significant myocardial protective effect. Key words: Cerium oxide ;  Myocardial ischemia;  Reperfusion injury ;  Apoptosis