Dose-Dependent Effects of ZnO Nanoparticles on the Osteogenic Differentiation Potential of Rat-Derived MSCs

Zinc oxide nanoparticles (ZnO NPs) have shown promise in bone tissue engineering applications due to their osteogenic properties. The purpose of this research was to analyze how varying doses of ZnO NPs modulate the in vitro rats bone marrow-sourced mesenchymal stem cells (MSCs) undergoing osteogenic conversion (OD). Sol-gel technique was employed to synthesize ZnO NPs, which were then analyzed using FTIR, XRD, and TEM. MSCs obtained from rat bone marrow were maintained in osteogenic medium containing ZnO NPs at 0, 10, 25, and 50 μg/mL concentrations. Assessment of cell viability was carried out using the MTT assay. OD was assessed by analyzing osteogenic marker gene expression (Runx2, OSX, and OCN), calcium deposition, and the alkaline phosphatase (ALP) activity, using real-time PCR. ZnO NPs were successfully synthesized and characterized, exhibiting a rod-shaped morphology with an average length of 50 nm. ZnO NPs at concentrations up to 25 μg/mL did not significantly affect cell viability. Calcium deposition and ALP activity were significantly enhanced in MSCs exposed to ZnO NPs at 10 and 25 μg/mL concentrations relative to the control. The expression of OCN, OSX, and Runx2 was significantly upregulated in a manner that is dependent on the dosage in ZnO NP-treated MSCs, with the highest expression levels observed at 25 μg/mL. ZnO NPs at concentrations up to 25 μg/mL enhance the OD of rat bone marrow-derived MSCs in vitro, as demonstrated by the escalation in calcium deposition, ALP activity, and upregulation of osteogenic marker genes. These findings indicate that ZnO NPs could serve as a promising bioactive agent in bone tissue engineering scaffolds to promote bone regeneration. To better understand the fundamental mechanisms and assess the in vivo performance of scaffolds containing ZnO NPs, further investigations are necessary.