Single-Cell Transcriptomics Analysis of the Pathogenesis of Tendon Injury.

Tendon injury repair has been a clinical challenge, and little is known about tendon healing scar generation, repair, and regeneration mechanisms. To explore the cellular composition of tendon tissue and analyze cell populations and signaling pathways associated with tendon repair, in this paper, single-cell sequencing data was used for data mining and seven cell subsets were annotated in the tendon tissue, including fibroblasts, tenocytes, smooth muscle cells, endothelial cells, macrophages, T cells, and plasma cells. According to cell group interaction network analysis, pattern 4 composed of macrophages was an important communication pattern in tendon injury. Furthermore, the heterogeneity of M1 macrophages in tendons, the correlation of KEGG enriched pathway with inflammatory response, and the core regulatory role of the transcription factor NFKB and REL were observed; in addition, the heterogeneity of T cell isoforms in tendons was found and indicated that different isotypes of T cells involve in different roles of tendon injury and repair. This study demonstrated the heterogeneity of M1 macrophages and T cells in the tendon tissue, being involved in different physiological processes such as tendon injury and healing, providing new thinking insights and basis for subsequent clinical treatment of tendon injury.