Hydroxyapatite Scaffolds with Mesenchymal Stem Cell-Conditioned Medium Enhance Bone Regeneration: Comprehensive In Vitro and In Vivo Validation.

Through the combination of cell-based therapies and 3-dimensional scaffolds, bone tissue engineering presents promising options for treatment of bone defects. In this study, we used an animal model to investigate the regenerative potential of hydroxyapatite scaffolds treated with mesenchymal stem cells-conditioned medium on bone tissue engineering (bone defect repair). Stem cells were cultured and identified by flow cytometry, which confirmed the high expression of mesenchymal markers (CD146, CD90, CD105) and minimal expression of the CD31 and CD45 hematopoietic markers. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay revealed that 3T3 cells in scaffolds treated with a conditioned medium were more viable than untreated controls. Scratch test revealed that cell migration in the treated scaffolds was significantly improved. Histological staining and histomorphometric analysis in a rat model with calvaria defects verified that the treated scaffolds significantly promoted bone regeneration. These findings highlight the potential of these hybrid scaffolds as effective and biocompatible strategy to advance bone tissue regeneration in clinical applications.