Spheroid Formation by Human Periodontium-Derived Cells: Characterization of Human Periodontal Ligament Fibroblast (HPLF) in Spheroid Formation

We previously reported that periodontium-derived cells could form spheroids and that the spheroids could be used for periodontal reconstructive therapy because they contained cells with proliferative activity and which produce extracellular matrix. In this study, we performed an immunohistochemical study on spheroids formed by human periodontal ligament fibroblasts (HPLFs), which play an important role in periodontal reconstruction, using the antibodies against osteocalcin (OC) and fibroblast growth factor (FGF). The results showed that HPLF could produce OC in the spheroid environment. Much more OC expression was observed on day 40 after spheroid formation, than on day 7. FGFs, which maintain tissue construction, and growth factor for mesenchymal cells, were also observed. We investigated the viability of the cells in the spheroids by using a fluorescent material fluorescein diacetate-propidium iodide; FD (A-PI), and found that almost all cells survived and that no dead colonies were observed. The finding that, HPLF in spheroids can express OC in vitro, and that OC expression appears to be affected by the spheroid environment. FGFs were also contained in the spheroids, so spheroids may be capable of being applied to periodontal reconstructive therapy.