High-throughput sequencing for analysis of macropahges from old and young mice.

Immune cells are essential for proper fracture healing. The goal of this study was to compare the transcriptional profiles of the CD45+ immune cells isolated from the healing fracture callus of old (24 month) and young (3 month) mice (C57BL/6). Analysis of all CD45+ cells was completed via single cell RNAseq. Additional analysis of the macrophages involved in fracture healing in old and young mice was performed via bulk RNAseq. We show that there were multiple subpopulations of macrophages that were transcriptionally heterogenous and present simultaneously within the fracture callus tissue. Attenuated healing in the old mice was associated with a transcriptional profile that shifted towards more pro-inflammatory phenotypes. Overall design: Transcriptional profiles of macrophages from the fracture callus of old and young mice