Effect Of Gold Nanoparticle On Autophagy Flux And Exosomes Secrete Of Mesenchymal Stem Cells

Objective: Autophagy and exosomes are ubiquitous biological phenomena in cells.Autophagy of bone marrow mesenchymal stem cells plays an important role in maintaining stem cells differentiation and cell anti-stress ability,and exosome secreted by bone marrow mesenchymal stem cells is involved in many physiological activities such as tissue damage repair and inflammation mediation.Nanomaterials are widely used in the field of biomedicine,such as bone marrow mesenchymal stem.However,the effect of spherical gold nanoparticles on autophagy and the secretion of stem cell exosomes remains unclear.Therefore,it is further clarified that the effect of gold nanoparticles on autophagy and the secretion of stem cell exosomes plays an important role in the biomedical applications of gold nanoparticles and in the study of stem cell exosomes.Methods: The Citric acid deoxidization method was used to reduce tetrachloroaurate by sodium citrate to synthesize spherical gold nanoparticles.The size of the nanoparticles was observed by using an electron microscope and the absorption peak of the UV-Vis spectrum of the nanoparticles was detected.Bone marrow mesenchymal stem cells(MSCs)were extracted,and 20 nm spherical gold nanoparticles were added into the stem cells.The effects of gold nanoparticles on the proliferation of stem cells were detected by CCK-8.Supernatants were harvested,exosomes were extracted by ultracentrifugation and subjected to transmission electron microscopy and nanoparticle tracking analyzer.Western Blot was used to detect the effect of gold nanoparticle on autophagy of stem cells.RFP-GFP-LC3 lentivirus was used to detect autophagy.Lysosomal acidity and alkalinity were detected by lysosome probe,and the change of intracellular endosome system was observed by electron microscope.Results: 1.The spherical gold nanoparticles synthesized by the Citric acid deoxidization method were uniform in size and spherical in shape,and the UV absorption peak was about 540 nm.The gold nanoparticles had good biocompatibility.The concentration of less than 30 ?g / ml had no obvious effect on the proliferation and morphology of stem cells influences.2.The amount of exosome secreted by the spherical gold nanoparticle-treated stem cells was significantly increased in the untreated group.A large number of nano-particles gathered in the multivesicles.3.Spherical gold nanoparticles after lysosomal alkaline treatment,autophagosomes with lysosomal fusion blocked.Conclusion: Spherical gold nanoparticles can block cell autophagy flow and effectively promote rat bone marrow mesenchymal stem cell secretion of exosomes.