| The outbreak of COVID-19 in China has been brought under control.Through follow-up of cured patients,it is found that most patients have different degrees of pulmonary fibrosis after discharge.Among them,severely ill patients have severe pulmonary fibrosis,which is characterized by idiopathic pulmonary fibrosis.IPF is a chronic,progressive and fibrotic lung disease,with the disease confined to the lungs.Mesenchymal stem cells have high differentiation potential and low immunogenicity,which can limit the development of lung inflammation.MSCs have been used in the treatment of various lung diseases,so in this experiment we continue to use MSCs to treat IPF.Studies have confirmed that one of the therapeutic mechanisms of MSCs is paracrine.The exosomes released by MSCs are one of the important components of paracrine factors.Some EXOs can replace the MSCs from which they are derived to perform similar functions in the treatment of certain diseases.IPF pathogenesis is confined to the lungs.In order to enhance the targeting of EXOs therapy,we use Fe3O4@PDA to magnetize EXOs,and apply an external magnetic field to attract EXOs to enrich at the targeted site.We first identified the characterization of h UCMSCs and EXOs,and determined that the separated and purified substances were h UCMSC-EXOs.We used TGF-β1 to induce A549 cells and Bleomyces-induced mice to build IPF in vitro and in vivo models.The results show that early infusion of Fe3O4@PDA magnetized h UCMSC-EXOs can alleviate the experimental IPF induced by bleomycin.The therapeutic effect of the in vivo model is better than h UCMSC-EXOs.Indirectly proves that MSCs treatment of IPF not only promotes tissue repair through direct differentiation,but also non-cellular direct action-paracrine also plays a vital role.This study enhanced the targeting of MSC-EXOs by magnetic targeting technology,providing a new strategy for IPF treatment and a new idea for cell-free biotherapy. |
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