Abstract:

AIM: To explore the relationship between Ero1α expression and ERS and apoptosis in rat hypoxia/reoxygenation cardiomyocyte model.  METHODS: The H9C2 cardiomyocytes were randomly divided into groups: control group, hypoxia /reoxygenation 1 h, 3 h, 6 h, 12 h group (H/R1 group, H/R3 group, H/R6 group, H/R12 group), 4-PBA+H/R6 group. H9C2 cardiomyocytes of control group were cultured under normal condition till the end of experiment. Cardiomyocytes of H/R group underwent hypoxia for 3 hours followed by reoxygenation for 1 h, 3 h, 6 h, 12 h. 4PBA were given 2 hours before hypoxia in the 4PBA+H/R6 group. Hoechst 33258 staining was used to observe the apoptosis of cells under fluorescence microscope. The protein expression of Ero1α, glucose-regulated proteins 78(Grp78), C/EBP homologous protein (CHOP), caspase-12 were detected by Western blot. RESULTS: Compared with the control group, the expression level of Ero1α protein increased with the time of reoxygenation. The expression of Ero1α increased significantly at 3 h after reoxygenation and reached high point at 6 h(compared with the control group, P<0.01).Grp78 increased significantly after hypoxia and reoxygenation (compared with the control group, P<0.01), reached a peak at 3 h after reoxygenation. The apoptosis rate was also significantly increased, of which the most significant was at reoxygenation 6 h. Take hypoxia 3 h reoxygenation 6 h as the observation point, the expression of Ero1α, GRP78, CHOP and Caspase-12 in H/R6 group was significantly higher than that in control group (P<0.01). After administration of 4PBA, Ero1α, GRP78, CHOP, Caspase-12 protein expression was significantly lower than that in H/R6 group (P<0.05, P<0.01). CONCLUSION: Hypoxia/reoxygenation can induce cardiomyocyte apoptosis and endoplasmic reticulum stress. The expression of Ero1α in cardiomyocytes induced by hypoxia/reoxygenation can be changed. The expression of Ero1α is related to apoptosis.

Key words: Ero1α, hypoxia/reoxygenation, endoplasmic reticulum stress, apoptosis, cardiomycytes