Abstract: Objective To explore the effect of RNA interferring programmed cell death 4(PDCD4) expression on apoptosis of hypoxia/reoxygenation（H/R） H9C2 cardiomyocytes and its mechanism.Methods H9C2 cardiomyocytes were divided into control group,H/R group,H/R+NC group and H/R+siPDCD4 group.Levels of PDCD4 mRNA and protein of H9C2 cardiomyocytes in 4 groups were detected by reverse transcription-polymerase chain reaction(RT-PCR) and Western blotting respectively.Apoptosis rates of them were detected by flow cytometry.Levels of malondialdehyde(MDA),superoxide dismutase(SOD) and lactate dehydrogenase(LDH) in supernatant of H9C2 cardiomyocytes were measured by enzyme Linked immunosorbnent assay(ELISA).Levels of the phosphatidylinositol-3-kinase(PI3K)/protein kinase B(AKT) signaling pathway related proteins were examined by Western blotting.Results Levels of PDCD4 mRNA and protein,activated Caspase-3,Bcl-2 related X(Bax) protein,LDH,MDA and apoptosis rate of H9C2 cardiomyocytes in H/R group were higher than those in control group,while levels of SOD in supernatant and Bcl-2 and p-AKT protein in H9C2 cardiomyocytes were lower than those in control group(P<0.05).Levels of PDCD4 mRNA and protein,activated Caspase-3,Bax protein,LDH,MDA and apoptosis rate of H9C2 cardiomyocytes in H/R+siPDCD4 group were lower than those in H/R group,while levels of SOD in supernatant,Bcl-2 and p-AKT protein in H9C2 cardiomyocytes were higher than those in H/R group(P<0.05).Conclusion RNA interferring PDCD4 expression can inhibit H/R induced H9C2 cardiomyocyte apoptosis,and its mechanism may be related with the activation of PI3K/AKT signaling pathway to reduce oxidative stress.

Key words: Hypoxia reoxygenation, Programmed cell death 4, Cardiomyocyte apoptosis, Phospoinositide-3-kinase/protein kinase B signaling pathway, Oxidative stress