Development of a 3D human osteoblast cell culture model for studying mechanobiology in orthodontics

Mechanobiology phenomena constitute a major element of the cellular and tissue response during orthodontic treatment and the implantation of a biomaterial. Better understanding these phenomena will improve the effectiveness of our treatments. The objective of this work is to validate a model of three-dimensional (3D) culture of osteoblasts to study mechanobiology.

The hFOB 1.19 cell line was cultured either traditionally on a flat surface or in aggregates called spheroids. They were embedded in 0.8% low-melting agarose type VII and placed in a polyethylene terephthalate transwell insert. Compressive forces of 1 and 4 g/cm2 were applied with an adjustable weight. Proliferation was evaluated by measuring diameters, monitoring glucose levels, and conducting Hoechst/propidium iodide staining. Enzyme-linked immunosorbent assays focusing on the pro-inflammatory mediators interleukin (IL)-6 and IL-8 and bone remodelling factor osteoprotegerin were performed to evaluate soluble factor synthesis. quantitative reverse transcription-polymerase chain reaction was performed to evaluate bone marker transcription.

The 3D model shows good cell viability and permits IL dosing. Additionally, three gene expression profiles are analysable.

The model allows analysis of conventional markers; larger exploration is needed for better understanding osteoblast mechanobiology. However, it only allows an analysis over 3 days.

The results obtained by applying constant compressive forces to 3D osteoblastic cultures validate this model system for exploring biomolecule release and analysing gene transcription. In particular, it highlights a disturbance in the expression of markers of osteogenesis.