小鼠CD11c+树突状细胞破骨向分化的实验研究OA

Objective:To investigate the in vivo and in vitro transdifferentiation capacity of murine CD11c-positive dendritic cells(CD11c+DCs)into osteoclasts,and to compare their osteoclastogenic differentiation potential with that of CD11b-positive monocytes(CD11b+MNs)and bone marrow monocytes(BMMs).Methods:A periodontitis model was established in C57BL/6 mice using silk ligation.Immunofluorescence staining was performed to examine the expression of CD11c and CD11b on cathepsin K(CTSK)-positive multinucleated cells in alveolar bone tissue on days 1,3,and 7 post-surgery.Primary murine CD11c+DCs and CD11b+MNs were isolated using immunomagnetic beads,and the expression of relevant cell surface markers was detected by flow cytometry.CD11c+DCs,CD11b+MNs,and BMMs were separately cultured and induced to differentiate into osteoclasts.Tartrate-resistant acid phosphatase(TRAP)staining and real-time quantitative polymerase chain reaction(RT-qPCR)were employed to assess the number of osteoclasts formed and the mRNA expression levels of osteoclast-related genes(Ctsk,Mmp9,Trap,and Nfatc1).Results:Immunofluorescence showed that CD11c expression was significantly upregulated in alveolar bone following periodontitis surgery,with a faster rate and greater trend of upregulation compared to CD11b.On day 7 post-surgery,the proportion of CD11c+CTSK+multinucleated cells among CTSK+multinucleated cells was significantly higher than that of CD11b+CTSK+multinucleated cells.Flow cytometry revealed that sorted CD11c+DCs exhibited low expression of CD80,CD86,and MHC-Ⅱ,while CD11b+MNs highly expressed Ly6C and F4/80 and did not express B220.In vitro experiments demonstrated that CD11c+DCs formed a significantly greater number of TRAP-positive multinucleated cells compared to CD11b+MNs and BMMs,with significantly elevated mRNA expression levels of osteoclast-related genes,including Ctsk,Mmp9,and Trap.Conclusion:Murine CD11c+DCs possess significant osteoclastogenic differentiation capacity and participate in the formation of CTSK+multinucleated cells in periodontitis.