In vitro evaluation of the bioactivity of Hydrogel, a new pulp-capping agent via pulpal stem cells

Objectives: The aim of this study was to evaluate the biocompatibility and osteoinductive properties of a two-component self-cured gel composed of bovine serum albumin and glutaraldehyde (Hydrogel) using the mouse pulp-derived stem cell line A4, which have an osteo/odontogenic potential in vitro and contribute to efficient bone repair in vivo.
Methods: A4 cells were cultured at the stem cell stage in the presence of Hydrogel discs for cell viability evaluations by the MTT assay on days 1, 3, 7 and 10. A4 cells without discs were used as control for MTT test. A4 cells were induced towards osteo/odontogenic differentiation to assess the impact of the Hydrogel on mineralization by Von Kossa and Alizarin red staining and to measure the expression of odontoblast markers (type 1 collagen, DMP1, DSP or BSP) by immunolabeling on days 7 and 14. Steady state A4 cells exposed to hydrogel discs was used as negative control.
Results: Exposure to Hydrogel did not alter the viability and morphology of A4 pulpal cells at the end of 10 days. Hydrogel preserved the intrinsic ability of A4 cells to express type 1 collagen, DMP1, DSP or BSP at the stem cell stage.
Conclusions: Hydrogel exhibited no cytotoxicity after 10 days. It did not recruit the pulpal stem cells towards differentiation but preserve their osteo-odontogenic intrinsic properties.