Analysis Of ?MSCs On The Regulation Of Neutrophil Migration And Cytokine Secretion In The Early Stage Of Myocardial Infarction

Objective:The object of this study was to investigate the effects of MSCs pretreated by IFN-?(yMSCs)on neutrophil migration and the secreted cytokines in vivo and in vitro one day after myocardial infarction,and to provide a theoretical basis and a feasible approach for stem cell treatment of myocardial infarction.Methods:In vivo:C57 female mice were selected as the experimental subjects,which entered the thoracic cavity through intercostal thoracotomy.And then we ligated the end of left anterior descending coronary artery(LAD)using 7-0 prolene suture,to establish the myocardial infarction model.MSCs pretreated with IFN-y were intramyocardial injected.We then observe the level of neutrophil infiltration in the myocardial infarction area of the mouse one day after myocardial infarction,and the Ly6G expression analysis was performed on the myocardial infarction tissue.At the same time,collagenase was used to digest the myocardial tissues and then through magnetic beads sorting.We then obtained and counted the individual neutrophils.In vitro:We first co-cultured bone marrow neutrophils with MSCs pretreated by IFN-?,and then placed the co-cultured neutrophils in chemotaxis medium to test for chemotactic ability.Western bolt was conducted on neutrophil to detect the expression level of TLR4,which was related to chemotaxis of neutrophil.RT-qPCR test was performed on neutrophils after co-culture to detect the expression level of pro-inflammatory and anti-inflammatory cytokines.Results:The Ly6G+neutrophils in cardiac tissues were significantly reduced by the MSCs pretreated with IFN-y in vivo.What's more,the single neutrophil was got through magnetic beads sorting and the number of neutrophils was in comparable with the immunofluorescence results.At the same time,RT-qPCR results showed that the expression level of Ly6G,a specific gene of neutrophils,was also reduced.In vitro co-culture results showed that IFN-y pretreated MSCs can reduce the ability of neutrophils to migrate to chemotactic media.In addition,the expression of TLR4 and proinflammatory cytokines expressed by neutrophils after co-culture is reduced by MSCs,while the expression of anti-inflammatory cytokines increased.Conclusions:In summary,we found that yMSCs can reduce the chemotaxis of neutrophils to myocardial infarction sites in vivo.At the same time,yMSCs can reduce the expression of neutrophil chemotactic receptors TLR4 and proinflammatory cytokines,and increase anti-inflammatory cytokines.Thus,we provided new ideas and approaches for clinical usage of MSCs in the treatment of myocardial infarction.