Thymoquinone loading into hydroxyapatite/alginate scaffolds accelerated the osteogenic differentiation of the mesenchymal stem cells

Background: Hydroxyapatite (HA) can be loaded by some osteogenic inducing agents such as thymoquinone (TQ) and alginate. This study was performed to investigate the effect of TQ loading into HA/alginate scaffolds on osteogenic differentiation capability of mesenchymal stem cells. Methods: : HA scaffolds were fabricated by casting and sintering method and impregnated by TQ containing alginate. The stem cells were loaded onto the scaffolds and induced to differentiate into osteoblasts. Alkaline Phosphatase (ALP) activity, Alizarin Red S, Real-Time qRT-PCR, and MTT assessments were done. Finally, the cells were examined with a light microscope, confocal microscope, and SEM. Results: : The results showed that the presence of the alginate decelerates the degradation rate and reinforces the mechanical strength. while the presence of TQ had no significant influence on physical and mechanical properties of the HA/alginate scaffolds, it led to a significant increase in ALP activity and expression of collagen, osteopontin, and osteocalcin at early phase of differentiation. Also, TQ administration had no impact on calcium deposition and proliferation as well as bone-marker expression at long term differentiation. Conclusion: TQ accelerates the differentiation of the stem cells into the osteoblasts without changing the properties of the scaffolds, and the HA/alginate/TQ scaffold can be used as a scaffold with osteogenic properties in bone tissue engineering applications.