动物造模,心肌缺血 z-bio 2022-09-30 422

　　Objective To investigate whether exosomes secreted by mesenchymal stem cells regulate cardiac autophagy through miR-21-5p and affect cardiac function in rats with myocardial ischemia.

　　Methods In vitro, the effects of MSCs-Exos on H9C2s stimulated by H2O2 were observed; cell viability was detected by CCK-8 assay; cell apoptosis was detected by flow cytometry; generation of reactive oxygen species (ROS) in cells was detected by fluorescence microscopy ; Western blot analysis of autophagy-related proteins and fluorescent GFP-LC3 to measure autophagosome formation. In the rat MI/RI model, the effects of MSCs-Exos on apoptosis, myocardial LC3B expression and cardiac function were examined by TUNEL assay, immunohistochemical staining and echocardiography, respectively.

　　Results In the in vitro experiments, MSCs-Exos significantly increased the viability of H9C2 cells stimulated by H2O2 (P<0.05), and decreased the production of ROS and the rate of apoptosis (P<0.05). Compared with the H2O2 +MSCs-Exos group, the cell viability of the H2O2 +MSC-ExossimiR-21-5p group was significantly decreased (P<0.01), and the production of ROS and the apoptosis rate were significantly increased (P<0.01). . Western blot analysis showed that compared with the H2O2 group, the expression of LC3B-Ⅱ/LC3B-Ⅰ and LC3B-Ⅱ in the H2O2 +MSCs-Exos group was significantly increased (P<0.01), and the expression of p62 was significantly decreased (P<0.01). 01); compared with the H2O2 +MSCs-Exos group, the expression of LC3B-II/LC3B-I and LC3B-II in the H2O2+MSC-ExossimiR-21-5p group was significantly decreased (P<0.05), and the expression of p62 Significantly enhanced (P<0.05). Autophagy flux results: Compared with the H2O2 group, the number of GFP-LC3 spots in the cells in the H2O2 +MSCs-Exos group increased; The number of GFP-LC3 spots present was significantly reduced (P<0.05). In vivo, RT-qPCR analysis showed that the expression of miR-21-5p was positively correlated in MSCs-Exos and in myocardial tissue after MI/RI. Compared with other groups, the expression of LC3B in MI/RI + MSCs-Exos group was significantly enhanced (P<0.01); cardiomyocyte apoptosis was significantly decreased (P<0.01); fractional shortening rate (FS%) and Left ventricular ejection fraction (LVEF) was significantly increased (P<0.05).

　　Conclusion MSCs-Exos can improve cardiac function in MI/RI rats by regulating myocardial autophagy, and its mechanism may be related to the transfer of miR-21-5p.