Establishment of an ex vivo pulpitis model by co‐culturing immortalized dental pulp cells and macrophages

Yonehiro J, Yamashita A, Yoshida Y, Yoshizawa S, Ohta K, Kamata N, Okihara T, Nishimura F. Establishment of an ex vivo pulpitis model by co‐culturing immortalized dental pulp cells and macrophages. International Endodontic Journal. Abstract Aim To establish an ex vivo pulpitis model by co‐culturing dental pulp cells with macrophages. Methodology As dental pulp cells, immortalized human dental pulp cells, named DP‐1, were used, whilst as macrophage cell lines, the differentiated human monocytic cell line, THP‐1, was used. In some experiments, primary dental pulp cells were isolated and used to confirm the results obtained in the experiments using immortalized cells. Co‐culturing was performed using transwell systems. Inflammatory responses were evaluated by measuring cytokines produced by the cells. Results Co‐culturing both cell types markedly up‐regulated inflammatory cytokine production as compared with the cells cultured independently, suggesting that both cell types interact with each other to synergistically produce higher amounts of inflammatory cytokines. Interestingly, both DP‐1 and primary dental pulp cells appeared to produce molecules stimulating macrophages to produce tumour necrosis factor‐α‐. Conclusion Co‐culturing immortalized dental pulp cells and macrophages may be a new ex vivo model for studying the pathophysiology of reversible pulpitis.