Taken together, the upregulated osteo-chondrogenesis and downregulated tenogenic differentiation potential of TDSCs in DM tendons might be contributed to the increased expression of OPN, OCN, Col II, and SOX9 and decreased expression of Col I and TNMD in diabetes tendons with IHC staining and further resulted in the decreased mechanical properties and degenerative changes, even characteristic tendinopathy alternations in DM tendons. Here, SOX9 is linked to diabetes mellitus.