The Role Of Dipeptidyl Peptidase Ⅲ In Hypoxia Reoxygenation Injury Of H9c2 Cardiomyocytes

Objective:To explore the role and mechanism of Dipeptidyl peptidase 3 in the hypoxia reoxygenation injury of H9c2 myocardial cells.Methods:In this experiment,H9c2 myocardial cells were divided into four groups:blank control group(Control group),hypoxia reoxygenation group(H/R group),negative transfection control+hypoxia reoxygenation group(NC si RNA+H/R group),and DPP3transfection knockdown+hypoxia reoxygenation group(DPP3 si RNA+H/R group).The morphological changes of myocardial cells in the four groups were observed using an inverted microscope,and the vitality changes of myocardial cells in the four groups were observed through the CCK-8 experiment,RT-qPCR and WB experiments were used to detect the mRNA and protein expression of the target gene DPP3 and KEAP1/Nrf2/HO-1 signaling pathway in four groups of cardiomyocytes,MDA、SOD kits were used to detect the level of oxidative stress in four groups of cardiomyocytes.Result:1.By means of microscopic observation and CCK-8 assay,it was determined that the number of cells in the Control group was(1.267±0.086)×10~6/m L with a cell survival rate of(100.0±1.901)%.The H/R group exhibited a lower cell count of(0.720±0.070)×10~6/m L with a decreased cell survival rate of(78.48±1.188)%.Similarly,the number of cells in the NC si RNA+H/R group was(0.553±0.045)×10~6/m L with a cell survival rate of(64.38±2.831)%,while the DPP3 si RNA+H/R group had the lowest cell count of(0.283±0.025)×10~6/m L with a significantly reduced cell survival rate of(40.31±1.451)%.A statistically significant difference in the degree of cell death was observed between the H/R and Control groups(P<0.005).Furthermore,the DPP3 si RNA+H/R group exhibited a more severe death phenomenon compared to the NC si RNA+H/R group,as evidenced by a further decrease in cell survival rate(P<0.005);2.RT-qPCR and WB and experiments showed that after hypoxia and reoxygenation of cardiomyocytes,the mRNA level and protein expression of the target genes DPP3,Nrf2 and HO-1increased,and the difference was statistically significant compared with the control group(P<0.05).After DPP3 gene knockdown,when cardiomyocytes underwent hypoxia reoxygenation test,the mRNA levels and protein expression of the target genes DPP3,Nrf2 and HO-1 were significantly reduced,and the difference was statistically significant compared with the NC si RNA+H/R group(P<0.05).3.After the hypoxia and reoxygenation test,the expression of MDA will increase,and the expression of SOD will decrease.Compared with the control group,the difference is statistically significant(P<0.05).After H/R,the expression of MDA was further increased,and the expression of SOD was further decreased in the DPP3 knockdown group.Compared with the NC si RNA+H/R group,the difference was statistically significant(P<0.05).Conclusion:1.H9c2 cardiomyocytes undergo significant oxidative stress reactions during hypoxia and reoxygenation experiments,causing cardiomyocyte damage.2.DPP3is a stress protein that participates in the pathological process of hypoxia reoxygenation injury in H9c2 cardiomyocytes.3.DPP3 is involved in the oxidative stress response of H9c2 cardiomyocytes during hypoxia/reoxygenation injury,and its mechanism may be related to the Nrf2/HO-1 signaling pathway.4.DPP3 may reduce the level of oxidative stress in H9c2 cardiomyocytes to reduce cell damage.