Decellularized tendon scaffold seeded with adipose-derived MSCs and supplemented with G-CSF injection promotes tendon repair in a rat model

Background Tendon injuries cause pain and functional limitations, posing a clinical burden due to poor healing and recurrence. Combining mesenchymal stem cells (MSCs), tissue-specific extracellular matrix (ECM) scaffolds, and bioactive factors may enhance tendon regeneration. This study investigated integrating adipose-derived MSCs (AD-MSCs) seeded on a decellularized tendon scaffold (DTS) with G-CSF injection for tendon repair. Methods DTS was prepared from rat Achilles tendons through freeze-thaw cycles and sodium dodecyl sulfate decellularization, preserving ECM structure. In vitro , AD-MSC viability, tenogenic gene expression, and scratch wound closure were assessed in response to G-CSF ± DTS. In vivo , a rat Achilles tendon defect model included: control (CTL), DTS, DTS with G-CSF, and DTS and AD-MSCs with G-CSF. After 6 weeks, histology, immunohistochemistry, collagen quantification, gene expression, and immunofluorescence analyses were performed. Results DTS maintained AD-MSC viability and tenogenic differentiation in vitro by upregulating SCX , COL1 , and TN-C . G-CSF (1000 ng/mL) enhanced AD-MSC-mediated wound closure in the presence of DTS extract. In vivo , DTS with AD-MSCs and G-CSF showed organized collagen alignment, reduced cellularity and inflammation, increased collagen deposition, and the highest total collagen content. Furthermore, it exhibited upregulation of SCX, TN-C, COL1 , THBS-4 , and DCN , an improved COL1/COL3 ratio, reduced IL-6 , MMP3 , and MMP13 , and increased IL-10 , CXCR4 , SDF-1 , CD34 , and CD31 compared with other groups. Conclusion DTS combined with AD-MSCs and G-CSF injection demonstrated the most favorable histological and molecular tendon repair profile, including enhanced tenogenic marker expression, improved ECM remodeling, increased homing- and vascular-associated marker expression, and modulation of inflammatory responses.