Isolation and Characterization of hUMSCs

hUMSCs were extracted using the tissue block culture attachment method, as previously reported [19 (link),20 (link)]. The preparation of P5 hUMSCs was conducted in a GMP facility following good clinical practice (GCP) guidelines. The identification of hUMSCs was detected by flow cytometry (BD Biosciences, FACSAria2, USA). The antibodies used in this experiment included CD73-BV421 (cat.562430, BD Biosciences, USA), CD105-APC (cat. 562408, BD Biosciences, USA), CD90-FITC (cat.555595, BD Biosciences, USA), HLA-DR-PE (cat. 555812, BD Biosciences, USA), CD34-PerCP-Cy™5.5 (cat. 347203; BD Biosciences, USA), and CD45-FITC (cat.555482; BD Biosciences, USA). Osteogenic differentiation medium (catalog#05465, STEMCELL Technologies, China), adipogenic differentiation medium (catalog#05412, STEMCELL Technologies, China), and chondrogenic differentiation medium (catalog#05455, STEMCELL Technologies, China) were used to assess the osteogenic, adipogenic, and chondrogenic differentiation potential of hUMSCs, following the manufacturer’s instructions. Oil Red O solution (O1391, Sigma-Aldrich, USA), Alizarin Red S (A5533, Sigma-Aldrich, USA), and Alcian Blue staining solution (TMS-010-C, Sigma-Aldrich, USA) were used for adipogenic, osteogenic, and chondrogenic staining, respectively, according to the manufacturer’s instructions.