Does chitosan modify immune response against fibrin hydrogel in dental pulp?

Objectives: One of the most significant challenge in modern dentistry is the maintenance of vital dental-pulp (DP). LBTI in Lyon developed a new fibrin-chitosan hydrogel that may support the proliferation and differentiation of dental pulp cells toward the functional regeneration of the pulp-dentin-complex after pulpotomy. Fibrin is a natural polymer offering many advantages like cytocompatibility and neutral immune response. However, its absence of antimicrobial activity may not resolve dental pulp infection. Chitosan, a natural polysaccharide obtained by partial deacetylation of chitin, has been shown to possess antimicrobial activity against a variety of bacteria present in the infected root canal. Chitosan is also known to modify immune response according to its acetylation degree. A moderate immune response is expected after biomaterials engraftment to manage healing/regeneration process. Thereby, we have evaluated whether chitosan modifies the immunogenic properties of fibrin-hydrogel in murine pulpotomy model.
Le nom du labo de JC Farge
Methods: Hydrogel with fibrin alone and fibrin-chitosan were injected in pulpal cavity realized in rat incisors. Gene expression of inflammatory mediators (IL-1β, TNF-α, IL-6, NOS2, IL-10, Arg1 and CCL2) were evaluated by qPCR 3h after engraftment. Cells recruitment was quantified by FACS analyses 1day after engraftment. Immuno-histo-labelling was realized 1, 3 and 7 days after engraftment.
Results: QPCR evaluations show that engraftment induced a moderate inflammation, only IL-6 expression was increased compared with control group. Chitosan did not modify genes expression of inflammatory mediators. FACS analyses showed the same modification of sub-population of leucocytes with fibrin and chitosan-fibrin compared with healthy pulp. The presence of M2 macrophage observed with immuno-histo-labelling nearby hydrogels was not influenced by chitosan.
Conclusions: Taken together, our data demonstrate that chitosan did not modify moderate inflammation induced by hydrogel, its allow us to consider evaluating this new biomaterial to regenerate dental pulp after pulpotomy