| Objective: Myocardial ischemia-reperfusion injury(MI/RI)is the further injury of myocardial tissue caused by the recanalization of coronary artery occlusion.The occurrence of MI/RI reduces the therapeutic effect of ischemic heart disease and myocardial infarction.It is found that the autophagy of MI/RI is closely related.Paeoniflorin(PF)is an effective monomer component in Paeonia lactiflora,which has a wide range of pharmacological activities.Our previous research shows that PF has a certain protective effect on myocardial ischemia-reperfusion injury in rats.On the basis of previous studies,this study further studied its effect on myocardial autophagy in MI/RI,and explored its signal pathway of regulating autophagy,revealing the mechanism of PF against MI/RI.Methods: 1.The effect of paeoniflorin on autophagy of myocardial cells after ischemia-reperfusion injury in rats.SD rats were randomly divided into Sham operation group,I/R group and I/R+PF group.In I/R+PF group,paeoniflorin(120mg/kg)was injected intraperitoneally once a day for three consecutive days.Sham group and I/R group were given the same amount of normal saline.I/R injury model was established by ligating the left anterior descending coronary artery for 30 min after the last administration and reperfusion for 120 min.Blood was collected from abdominal aorta for myocardial enzyme detection(CK-MB,LDH).The expression of LC3 in myocardial cells was observed by immunofluorescence,apoptosis was detected by TUNEL staining,ultrastructure of myocardium was observed by transmission electron microscope,the activity of Cathepsin B in lysosomes was detected by ELISA,and the expressions of p62,Beclin-1,LC3I/LC3 II,PINK1 and Parkin protein were detected by Western blot.2.The effect of paeoniflorin on autophagy of myocardial cells in H/R group.The experiment was divided into Control group,Control+PF group,H/R group and H/R+PF group.The model of H/R injury of H9C2 cardiomyocytes was established,the ultrastructure of cardiomyocytes was observed by transmission electron microscope,the m PTP opening degree of mitochondria was detected by immunofluorescence,and the expressions of p62,Beclin-1,LC3I/LC3 II,PINK1 and Parkin protein in cardiomyocytes were detected by Western blot.Results: 1.Compared with Sham group,the activities of CK-MB,LDH and apoptosis rate of myocardial enzymes in I/R group increased significantly,the expression of LC3 protein increased significantly,the content of Cathepsin B increased significantly,the expressions of LC3I/LC3 II,p62 decreased significantly,and the expressions of Beclin-1,Parkin and PINK1 protein increased significantly.Compared with I/R group,PF can significantly reduce myocardial enzyme content,inhibit myocardial apoptosis,reduce myocardial ultrastructural damage,inhibit the expression of autophagy protein LC3,Cathepsin B,Beclin-1,Parkin and PINK1,and up-regulate the expression of p62,LC3I/LC3 II.2.Compared with the Control group,the cell ultrastructure of H/R group was damaged,the m PTP opening degree was significantly increased,the expressions of p62,LC3I/LC3 II were significantly decreased,and the expressions of Beclin-1,Parkin and PINK1 were significantly increased.PF can obviously improve the ultrastructural damage of myocardial cells after H/R,inhibit the opening of mitochondrial m PTP,reduce the expressions of Beclin-1,Parkin and PINK1,up-regulate the expressions of p62,LC3I/LC3 II,and inhibit autophagy of myocardial cells.Conclusion: 1.PF can alleviate myocardial ultrastructural damage caused by myocardial I/R,inhibit the opening of m PTP,protect mitochondria,inhibit the expression of autophagy protein LC3,Beclin-1 and Cathepsin B,up-regulate the expression of p62,LC3I/LC3 II,inhibit autophagy of myocardial cells and inhibit the release of myocardial enzymes,thus playing a role in protecting myocardium.2.PF can inhibit the high expression of PINK1 and Parkin,inhibit the over-activation of PINK1/Parkin pathway,reduce mitochondrial autophagy,protect mitochondria and play a protective role in myocardium. |
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