Anti-inflammatory and immunomodulatory effects of Biodentine on human periapical lesion cells in culture

Abstract

Aim: To evaluate the effect of Biodentine eluate on cytotoxicity and production of pro- and anti-inflammatory cytokines and osteodestructive/osteoprotective cytokines in cultures of human periapical lesion cells.

Methodology: Conditioned Biodentine Medium (CBM) was prepared according to ISO 10993-12, by incubating Biodentine in RPMI medium (0.2 g mL^-1 ) for 3 days at 37 °C. CBM contained both released microparticles and leachable soluble components. Inflammatory cells were isolated from 22 human periapical lesions after apicectomy or tooth extraction, by collagenase/DNase digestion, and cultured in several dilutions of CBM. The composition of periapical lesion cells was determined by morphological criteria, cytotoxicity was quantified by MTT and flow cytometric apoptosis/necrosis assays, whereas the levels of produced cytokines in cell culture supernatants were measured by flow cytometry and ELISA. Student t-test and Friedman test with Dunn's post-test were used for comparison of parametric and nonparametric variables, respectively.

Results: Undiluted (100%), 75% and 50% CBM were cytotoxic for periapical lesion cells due to induction of both necrosis (100% CBM) and apoptosis (75% and 50% CBM). Noncytotoxic concentrations of CBM (25%) inhibited the production of pro-inflammatory cytokines: TNF-α, (P < 0.005); IL-1β (P < 0.01); IL-6 (P < 0.005) and chemokines IL-8: (P < 0.005); MCP-1 (P < 0.005), stimulated the production of anti-inflammatory cytokine (IL-10; P < 0.005), Th2 cytokines: IL-4, IL-5 and IL-33 (all P < 0.01), and IL-17A (P < 0.01). The concentration of CBM (12.5%) inhibited the production of IL-6 (P < 0.05), IL-8 (P < 0.01) and MCP-1 (P < 0.005) and augmented the production of IL-10 (P < 0.05). No significant effects on Th1-related cytokines (IFN-γ and IL-12) and IL-23 were detected with 25% and 12.5% CBM concentrations. Both CBM concentrations inhibited the production of osteolytic receptor activator of nuclear factor kappa-Β ligand (RANKL), dose dependently (P < 0.005 and P < 0.01, respectively). Higher CBM concentrations decreased RANKL/osteoprotegerin (OPG) ratio (P < 0.05), without significant influence on the levels of osteoprotective OPG.

Conclusion: Biodentine possesses immunomodulatory properties by suppressing pro-inflammatory and augmenting anti-inflammatory cytokines. Together with the reduction of osteodestructive mediators, this novel root-end filling cement could be beneficial for healing and bone reparation after the surgical treatment of periapical lesions.

Keywords: Biodentine; cell culture; cytokines; cytotoxicity; periapical lesion.