Adipose Mesenchymal Stem Cell Exosome Relieving Acute Myocardial Injury Induced By Doxorubicin

Background:Anthracyclines are common clinical chemotherapeutic drugs.Myocardial injury is the main injury caused by anthracyclines,and it is also an important factor limiting their application.Therefore,how to alleviate the myocardial injury caused by anthracycline drugs is an urgent problem to be solved.In the study of tissue injury,stem cells and their derived exosomes(EXO)have been found to be promising targets for the treatment of tissue and organ injury in recent years,and the understanding of adult mesenchymal stem cells has greatly expanded the source of EXO.It has been reported that EXO can not only play a protective role similar to stem cells in tissue injury,but also has more biological safety advantages,but its specific mechanism is still under discussion.Current studies suggest that stem cell EXO may play a therapeutic role by participating in the regulation of microenvironment.The aim of this study was to explore the protective effect and possible mechanism of EXO derived from adipose stem cells on myocardial damage induced by anthracyclines.Objective:The aim of this study was to investigate the mitigation effect of EXO derived from adipose-derived mesenchymal stem cells(ADSCs)on acute myocardial injury induced by doxorubicin(DOX)and its molecular mechanism,so as to provide reference for its application in clinical cardiac injury induced by anthracycline drugs.Methods:Adipose tissue was isolated from axillary part of C57BL/6 mice aged 2-3 weeks for primary isolation of adipose stem cells.Flow cytometry was used to identify the expression of protein on the surface of isolated cells(CD29,CD34,CD44,CD45,CD90,CD105).Three lines(adipogenic,osteogenic and chondrogenic)were used to identify the differentiation ability of isolated cells.EXO Obtained by Differential and Ultra-Speed Centrifugation Particle size was measured by light scattering method,morphology was observed by fluoroscopy and electron microscopy,and protein markers(CD9,CD63,CD81,TSG101)were detected by immunoblotting.DOX-induced myocardial injury model of C57BL/6 mice was divided into PBS group,DOX group and(DOX+EXO)group.The protective effect of adipose stem cell-derived EXO on DOX-induced acute myocardial injury was verified by detecting the changes of electrocardiogram and myocardial marker proteins in different groups of mice.Myocardial cell(H9C2)experiment: To explore the molecular mechanism of adipose stem cell EXO in alleviating DOX-induced acute myocardial injury by detecting ROS levels,apoptotic differences,MDA and LDH levels in different groups.Results: 1.The separated cells showed regional whirlpool morphology when they were full-grown;adipose droplets,bone tissue and cartilage tissue could be formed by differentiation induction;CD29,CD90,CD105 and CD44 were positive on the cell surface,while CD34 and CD45 were negative,which proved that the separated cells were adipose-derived mesenchymal stem cells.2.Fluoroscopy electron microscopy showed that the separated vesicles were cup-shaped with one side depressed;light scattering detection showed that the size distribution of these vesicles was 50-200 nanometers wide;immunoblotting detection showed that CD9,CD63,CD81,TSG101 were positive,which accorded with the characteristics of EXO described in the literature.3.In animal experiments,the right atrial pressure of mice in the(DOX + EXO)group was significantly lower than that in the DOX group(P < 0.05),QRS and QTcB decreased to some extent,but there was no statistical difference;the cTnT of mice in the(DOX + EXO)group was lower than that in the DOX group(P < 0.05);HE staining,TUNEL staining and caspase-3 immunohistochemical staining showed that the(DOX + EXO)group had some relief compared with the DOX group.4.Cell experiments showed that EXO could be ingested by cardiomyocytes,and moderate amount of EXO could reduce ROS production and apoptosis of cardiomyocytes induced by DOX to a certain extent.Conclusions: Appropriate EXO can alleviate DOX-induced acute myocardial injury in mice to some extent,alleviate arrhythmia and protect cardiac function.Its possible molecular mechanism is to alleviate myocardial inflammation and cell apoptosis and necrosis caused by oxidative stress,which has potential clinical application value.