Seeding Osteoblasts onto Osteocytes: An In Vitro 3D Study

Understanding the mechanisms by which bone cells communicate is vital in exploring diseases characterized by bone degeneration, namely, osteoporosis. Cell seeding has been used in two dimensional (2D) cell cultures to study how bone cells interact with one another, specifically, to prove the existence of gap junctions between osteocytes and osteoblasts. However, the natural three dimensional (3D) state of bone tissue requires examining it in 3D. Accordingly, the cell seeding procedure was tested on trabecular bone core explants to ascertain whether it is useful in 3D studies as well. When the dye concentrations taken from past 2D experiments were used, Day 1 showed many osteoblasts, but by Day 2 the cells were not visible. The dye concentrations were then doubled to determine if the osteoblasts were still seeded onto the bone cores and viable but not visible, or if they had actually died. With these dye concentrations, the stained osteoblasts were still visible on the second day after seeding, indicating that the cells were seeded and living. According to these results, it is evident that with minor modifications of the 2D procedure, it is possible to seed osteoblasts onto osteocytes in 3D, making this a credible test for the presence of gap junctions in 3D bone tissue.