Expression of Osteoclastogenesis Inducers in a Tissue Model of Periodontal Ligament under Compression

There is increasing interest in the development of new in vitro tissue models. In this study, a tissue model of periodontal ligament (PDL) was established by 3-D-culturing human PDL cells in a thin sheet of porous poly (lactic-co-glycolic acid) scaffold. Growth of the model was evidenced by MTT assay and various microscopies. After being subjected to static compression of 5 ~ 35 g/cm 2 for 6 hrs, the RANKL mRNA expression was significantly up-regulated by force ≥ 25 g/cm 2 in the model. After being subjected to static compression of 25 g/cm 2 for 6 ~ 72 hrs, the mRNA expression of PTHrP, IL-11, IL-8, and FGF-2, potential osteoclastogenesis inducers, was significantly up-regulated in the model, which was further verified by the compression of human PDL in vivo. However, when human gingival fibroblasts were substituted for PDL cells in the model, almost no osteoclastogenesis inducers were up-regulated by compression. This tissue model can serve as an effective tool for the study of PDL mechanoresponse. Abbreviations: periodontal ligament, PDL; periodontal ligament cells, PDLCs; poly (lactic-co-glycolic acid), PLGA; orthodontic tooth movement, OTM; extracellular matrix, ECM.