Protective Effect Of Novel Synthetic Compound DIMO Postconditioning On Myocardial Ischemia-reperfusion Injury In Rats

ObjectiveTo investigate whether DIMO played a protective role on myocardial ischemia-reperfusion injury, and to try to explore its possible mechanism.MethodsEighty-six male rats were established acute myocardial I/R injury model in vivo. All rats were randomly divided to four groups: Sham group, I/R group, DIMO-1 group, DIMO-2 group. All rats except Sham group received left anterior descending coronary artery occlusion followedby 4 hours reperfusion in vivo. At the end of reperfusion, infarction was analyzed with TTC histology, cardiac microtubule-associated protein 1 light chain 3(LC3) I and II, Cathepsin B, Cathepsin L, P62 and Beclin-1 were determined. Western blot and Co-Immunoprecipitation were used to analyse the expression of RIP1 K protein. In vitro, oxygen and glucose deprivation(OGD) was used to establish the cardiomyocytes ischemia model. The cardiomyocytes were divided to four groups: non-OGD group, non-OGD+DIMO group, OGD/R group, OGD/R+DIMO group. After OGD 3 h, then reoxygenation 12 h. LDH leakage and Annexin-V/propidium iodide(PI) staining were detected to measure the cell injure. LC3, Cathepsin B, Cathepsin L, P62 and Beclin-1 were detected by western blot.ResultsVivo experiments:Compared with the Sham group, infarct size was increased, pathological damage was aggravated, the expression of Cathepsin B, Cathepsin L, Beclin-1, LC3 II/I and P62 were up-regulated(P< 0.05), and the expression of RIP1 K was up-regulated(P< 0.05).Compared with the I/R group, infarct size was decreased, pathological damage was alleviated, the expression of Cathepsin B, Cathepsin L, Beclin-1, LC3 II/I and P62 were down-regulated in the DIMO-1 and DIMO-2 groups(P< 0.05), the expression of RIP1 K was down-regulated(P< 0.05).Vitro experiments:Compared with the non-OGD group, the expression of Cathepsin B, Cathepsin L, Beclin-1, LC3 II/I and P62 were up-regulated(P< 0.05), and the expression of RIP1 K was up-regulated(P< 0.05) in the OGD/R group, and the LDH leakage and the number of necrosis and apoptotic cells were increased(P< 0.05).Compared with the OGD/R group,the expression of Cathepsin B, Cathepsin L, Beclin-1, LC3 II/I and P62 were down-regulated(P< 0.05), and the expression of RIP1 K was down-regulated(P< 0.05) in the OGD/R+DIMO group, and the LDH leakage and the number of necrosis and apoptotic cells were decreased(P< 0.05).ConclusionDIMO has protective effect in cardiomyocyte IR injury, which may be through decreasing necroptosis and autophagy in myocardial tissues.