We hypothesized that fracture fixation with a smaller pin would permit greater interfragmentary strain resulting in increased total amount of vascular endothelial growth factor within the callus and greater angiogenesis compared to fixation with a larger pin.
Real-time and Fluorescence- Activated Cell Sorting (FACS) results demonstrated that standard Thymoquinone and callus extracts down-regulated the VEGF-A gene expression, and all three induced apoptosis in the AGS cell line.
Within 7 days postfracture, treatment with STO-609 resulted in enhanced Indian hedgehog signaling, paired-related homeobox (PRX1)-positive mesenchymal stem cell (MSC) recruitment, and chondrocyte differentiation and hypertrophy, along with elevated expression of osterix, vascular endothelial growth factor, and type 1 collagen at the fracture callus.
Compared to the control, ADSC<sup>bFGF</sup> treatment increased VEGF expression at the periosteal region of the callus, remodeling of collagen into mineralized callus and bone strength.
Based on our data, local administration of VEGF in the callus to stimulate revascularization, or transplantation of stem cells to enhance bone turnover represent potentially feasible approaches to improve outcomes in clinical practice.
Furthermore, qRT-PCR analysis showed a 1-fold upregulation in mRNA levels of transforming growth factor beta and roughly 6-fold increases in vascular endothelial growth factor mRNA expression in calluses from the tanshinol groups.