Cellular Heterogeneity And Spatial-Temporal Landscapes In Mouse Condylar Cartilage

To explore the cell composition and spatial distribution characteristics of mouse condylar cartilage at different ages by single-cell sequencing technology. C57BL/6J wild-type mice(3 days, 3 weeks, 8 weeks, and 16 months); Single-cell digestion and sequencing; Cluster generation and labeling; Cell–cell interaction analysis; Pseudotime analysis; Movat Pentachrome stain; Fluorescence in situ hybridization (FISH); Isolation and Culture of CD168+ Progenitor Cells and CD90+ Mural Cells from Condylar Cartilage; Magnetic Bead Sorting of CD90+ Mural Cells from Condylar Cartilage 5-Ethynyl-2′-deoxyuridine (EdU) labeling assay; Colony formation assay; Multilineage differentiation Mouse condylar chondrocytes can be characterized using three markers, Sfrp2, Acta2 and Chad, where the Sfrp2+ cells located in the superficial layer, the Acta2+ cells located in the proliferative layer and some superficial layers, and the number of cells decreased gradually with aging, while the Chad+ cells located in the mature layer showed an opposite trend. In parallel, we identified a population of progenitor cells that specifically highly expressed Birc5 which Cell cycle analysis showed were in mitotic phase. BIRC5+ progenitor cells persist throughout the lifespan, albeit with a decline in number with age, remaining primarily localized in the fibrous and proliferative layers of the middle and posterior regions of the condylar cartilage. The subtypes of mouse condylar chondrocytes change with age, and the number of progenitor cells decreases with age.