Experimental Study Of Injectable Conductive Material Combined With Cardiomyocytes Derived From Endometrial Mesenchymal Stem Cells To Repair Myocardial Infarction In Rats

Objective:To investigate the efficacy of injecting polypyrrole-chitosan（Ppy-Chi）combin ed with Human endometrial mesenchymal stem cells derived cardiac myocytes（h E MSCs-CMs）in treating chronic left ventricular myocardial infarction in rats.Methods:Using Fe Cl₃as the redox agent,a one-step redox method was used to graft polypyrrole onto biomaterial chitosan to construct a Ppy-Chi conductive composite material,and glutaraldehyde was used as a crosslinking agent to agglomerate to f orm a hydrogel.In vitro,scanning electron microscope observation of the surface particle size and porous structure;cyclic voltammetry to detect the electrical cond uctivity of composite materials;through co-cultivation of endometrial mesenchymal stem cells to study their biocompatibility;The agglutination and degradation char acteristics were studied by in vitro agglutination time and mass loss with time.Th e EMSCs were separated by a complex enzymatic hydrolysis method,Enzymolysis was used to isolate endometrium-derived mesenchymal stem cells,and the cells were subcultured.Use flow cytometry to detect its surface markers;The multidire ctional differentiation of endometrium-derived mesenchymal stem cells（MSCs）was detected by induction differentiation assay.In vivo,the left anterior descending b ranch of the rat heart was ligated to prepare a myocardial infarction model,electr ocardiogram and PET-CT were used to evaluate whether the model was successful ly prepared.Four weeks after the preparation of myocardial infarction model,inje ction therapy was performed.The animals were randomly divided into 4 groups（P py-Chi-EMSCs-CMs,Ppy-Chi,EMSCs-CMs,control group）,the above materials w ere injected into the myocardial infarction area and the surrounding area of the ra ts respectively,and the cardiac function of the rats was evaluated by ultrasound.Results:In this study,Ppy-Chi conductive hydrogel was successfully constructed.Comp ared with the control group Chi hydrogel,Ppy-Chi hydrogel has a porous structur e,its surface is rough and granular,and it has good electrical conductivity.Both P py-Chi and Chi hydrogels can support the growth and proliferation of cells,and t he materials have good biocompatibility.These results indicate that the newly const ructed composite material is an ideal cell carrier.Compared with Chi hydrogel,Pp y-Chi hydrogel is more stable,which is conducive to its long-term function in the body.Enzymatic hydrolysis method can be used to isolate endometrium-derived m esenchymal stem cells successfully,and the cells can be subcultured.The endometri um-derived mesenchymal stem cells showed adherent growth.Flow cytometry sho wed high expression of CD44,CD73,CD90,and CD105 on the cell surface（>95%）,while low expression of CD11b,CD34,CD45,and HLA-DR（<5%）,indica ting that the stem cells used in this study were uterine mesenchymal stem cells with high purity.In addition,it was proved that endometrium-derived mesenchymal stem cells have good differentiation potential in the detection of multidirectional cell type differentiation.In vivo experiments,the present study successfully establis hed a rat model of myocardial infarction,and the electrocardiogram showed patho logical Q waves after ligation of the left anterior descending coronary artery.When Ppy-Chi-EMSCS-CMs myocardial tissue was used for the treatment of myocardia l infarction in rats,echocardiography showed that ejection fraction and FS%were improved.Preliminary exploration of the ¹⁸F-FDG Micro PET/CT showed that it co uld visually observe the area of myocardial infarction.Conclusion:Ppy-Chi combined with EMSCS-CMs can enhance the recovery of cardiac fu nction after myocardial infarction,providing a new treatment strategy for ischemic cardiomyopathy.