Photobiostimulation Enhances the Osteogenic Differentiation of Gingival-Derived Stem Cells Seeded on Nanocomposite Scaffolds

Purpose

This study was conducted to evaluate the effect of low-level laser therapy (LLLT) and cross-linked, nanofibrous, polycaprolactone/alginate scaffolds (PCL-NFs/Alg) on osteogenic differentiation of gingival mesenchymal stem cells (GMSCs) to develop a cell delivery system capable of enhancing bone regeneration.

Methods

Rat GMSCs were isolated, and scaffolds were fabricated. A four-group study was designed; negative control (GMSCs + complete media), positive control (GMSCs + osteogenic supplement (OS)), scaffold (GMSCs/scaffold + OS), and scaffold/LLLT groups (GMSCs/scaffold + OS + LLLT). Diode laser LLLT was performed every 48 h. Samples were evaluated after 7 or 14 days. Cell proliferation was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Mineralization and osteogenesis were evaluated by alizarin red S (ARS) and Von Kossa staining, beside real-time quantitative polymerase chain reaction (RT-qPCR), followed by statistical analysis.

Results

For scaffold characterization, scanning electron microscopy confirmed the nanofibrous structure, EDX analysis showed signals of relevant elements, and FTIR spectrometry revealed the characteristic peaks of the polymeric constituents. Mechanical and water contact angle measurements reported improved results compared to the non-coated scaffolds. MTT assay revealed statistically significant increase in cell proliferation in scaffold/LLLT group. ARS and Von Kossa staining revealed the highest mineralization in scaffold/LLLT group. RT-qPCR showed significant increase in OCN, ALP, and RUNX-2 expression in positive control, scaffold, and scaffold/LLLT groups respectively. However, OPN and COL1a1 showed low expression levels.

Conclusion

GMSCs have high osteogenic differentiation potential. Fabricated scaffolds possess good osteoconductive properties. LLLT significantly enhances cellular proliferation, and osteoblastic differentiation. Therefore, GMSCs-PCL/Alg-LLLT model can represent a promising choice for bone tissue engineering.

Lay Summary and Future Works

A tissue engineering triad composed of GMSCs and nanofibrous PCL/Alg scaffold together with LLLT proved high potential for promoting cell proliferation, osteogenesis, and tissue mineralization in vitro. Experimental trials on animal bone defect models are required in future studies as a translational step towards clinical application of the constructed model.

Graphical Abstract