The Mechanism Of Tricalcium Phosphate And Platelet-rich Fibrin Regulating Macrophage Polarization & Case Report

Part 1 Tricalcium phosphate promotes bone defect repair mechanism by regulating macrophage polarizationObjectives:In this paper,the polarization of osteogenesis of macrophages induced by TCP is studied.The role of TCP in polarizing macrophages is studied,and the role of EZH1 downregulation in macrophage-mediated TCP's promotion of bone defect repair is further investigated.Materials and methods:A mouse femur defect model was constructed in vivo.The experimental group was implanted with biological material TCP at the defect site,and samples were taken at one day and eight weeks.Sectional staining was used to observe the macrophage infiltration around the material and TCP bone defect repair after eight weeks.Thp1 was stimulated with TCP in vitro to detect macrophage polarization and EZH1 expression,and Thp1 supernatant was used to stimulate human osteoblasts to detect the promotion of osteogenic differentiation.Furthermore,siRNA knockdown EZH1 was used to detect the regulation of TCP on macrophage polarization and its osteoblast differentiation.Results:This study found that histone methyltransferase EZH1 was significantly down-regulated in TCP-stimulated Thp1,suggesting that EZH1 may be involved in macrophage polarization and osteogenic differentiation of hBMSCs.The experimental results also show that the NF-?B pathway also shows activation inhibition under the stimulation of TCP,indicating that there is an interaction between EZH1 and the NF-?B pathway.We have found that down-regulation of EZH1 can induce polarization of M2 macrophages,but does not directly lead to inhibition of NF-?B pathway activation.With the inhibition of the NF-?B pathway,the expression of EZH1 was significantly down-regulated,indicating that the inhibition of EZH1 is regulated by the NF-?B pathway.These findings reveal the role of epigenetics in immune osteogenesis and provide new ideas for macrophage polarization and microenvironment regulation of bone defect repair.Conclusion:TCP can inhibit the activation of NF-?B pathway,and then down-regulate the expression of EZH1.The down-regulation of EZH1 reduces the expression of macrophage M1 to marker genes,which can build a microenvironment with reduced expression of proinflammatory factors,which is more conducive to tissue regeneration and repair of bone defects.Part 2 Platelet-rich fibrin regulates macrophage polarization and its preparation improvementObjectives:The purpose of this study was to investigate the effect of platelet-rich fibrin on the proliferation,migration and polarization of macrophages.Materials and Methods:The PRF was prepared using a fixed angle and horizontal centrifugation scheme,and the appearance and quality of the prepared product were evaluated.Observe the PRF fiber results under a scanning electron microscope to observe the density of the fiber network.Whole blood was used as a control group,and PRF extract was used to stimulate Thp1 macrophages,CCK8 was used to detect Thp1 proliferation,Transwell experiment was used to detect Thp1 proliferation,RT-PCR was used to detect macrophages M1,M2 to surface markers Biological transcription to study the proliferation,migration,and polarization of macrophages under different stimuli.Results:The PRF prepared by the horizontal centrifugation scheme is heavier and larger in size,and the density of the fiber network is also higher,which facilitates the aggregation of more cells and cytokines.The results show that PRF promotes the proliferation and recruitment of surrounding macrophages,can significantly induce macrophages to M1 polarization which is beneficial to early antibacterial,and compared with PRF prepared by fixed-angle centrifugation scheme,horizontal centrifugation scheme The prepared PRF has greater potential in the proliferation and recruitment of macrophages,and can better induce the polarization of macrophages M1.Conclusion:This paper studies the effects of platelet-rich fibrin on the proliferation,migration and polarization of macrophages,and finds that platelet-rich fibrin can significantly promote the proliferation and migration of macrophages and can induce macrophages to microorganisms in the early stage of tissue repair.The defensive M1 is polarized.The cytokines,transcription factors or epigenetic modifiers induced by PRF and the specific mechanisms of macrophage polarization remain to be further studied.