Cytokine Release from Human Dentine

Human dentine contains a cocktail of growth factors and other bio-active molecules. Data indicate that when these molecules are released due to either disease or restorative processes they subsequently stimulate pulpal defence and repair mechanisms that involve cellular recruitment and activation. Little data currently however exists on cytokine/chemokine content of dentine. Objectives: To examine the cytokine/chemokine content of human dentine, obtained by extraction with EDTA, lactic acid and calcium hydroxide solutions, using antibody array technology. Methods: Dissected, powdered sound human dentine was extracted with solutions of 0.02M calcium hydroxide, pH 11.7, 0.1M lactic acid pH 4.0 or 10% EDTA, pH 7.2 for 14 days. Solubilised material was dialysed against water and lyophilised. Dentine matrix components were rehydrated and cytokine content was determined using both the qualitative ProVision^™ (Schleicher and Schuell, Germany) and quantitative Proteoplex^™ (Merck Biosciences, UK) human cytokine antibody array systems. Results: The ProVision^™ system detected the presence of angiogenin, IL-8, ICAM-1, IL-10, IL-1b, TGF-b1, IL-6, TNF-a, TNF-RII and VEGF in dentine matrix components obtained using all solutions although detection was less consistent in calcium hydroxide extracts. Analysis using Proteoplex^™ antibody arrays detected the presence of IL-1a, IL-1b, IL-4, IL-6, IL-8, IL-12 and GM-CSF. Highest levels of detection were found for IL-8 which was present in all extracted dentine matrix components (range: 20-99 pg/mg). All other detected cytokines were found to be present at less than 20 pg/mg and also exhibited variable levels within the different extracts. Conclusions: The release of cytokines during the dental disease process or due to restorative procedures may modulate the complexity of tissue events which occur during tissue injury and repair in the dentine-pulp complex.