Influence of static forces on the expression of selected parameters of inflammation in periodontal ligament cells and alveolar bone cells in a co-culture in vitro model

Abstract

Objective: Aim of this study was to investigate the impact of human PDL-derived fibroblasts (HPDF) and human alveolar bone-derived osteoblasts (HABO) co-culture on the expression of cytokines involved in tissue remodeling using an in vitro compressive force (CF) model. Materials and methods: Static compressive force (CF) of 47.4 g/cm 2 was applied on mono- and co-cultured HPDFs and HABOs for 1, 2, or 4 h at 30 °C. TNFA, PTGS2, and IL6 gene expressions were determined by quantitative real-time polymerase chain reaction. TNF, PGE 2 , and IL6 concentrations were measured using enzyme-linked immunosorbent assay. Results: In mono-culture, TNFA, PTGS2, and IL6 gene expressions were upregulated under CF as compared to controls for each time period in both cell types. PGE 2 increased at 1 and 2 h in both cell types, and IL6 increased only at 2 and 4 h in HPDFs. Co-culture alleviated the force-induced increase of the expression of TNFA, PTGS2, IL6, PGE2, and IL6 in HPDFs at any time point. In HABOs, co-cultivation decreased the expression of PGE 2 after 1 h and 4 h, and that of IL6 after 1 h compared to mono-culture. Conclusions: CF application on co-cultures of HPDFs and HABOs causes significant changes of TNFA, PTGS2, and IL6 gene expressions and PGE 2 and IL6 production in comparison to mono-culture indicating intercellular communication. Clinical relevance: Mechanical stimulation of HPDFs and HABOs in co-culture induces a different gene expression pattern than stimulation of individual cell types alone. Co-culture might therefore be a relevant method to elucidate periodontal regeneration during orthodontic therapy.