Methylsulfonylmethane Induces Dentinogenesis via a Canonical Pathway in Rat Dental Pulp Cells

Background/Objectives: Methylsulfonylmethane (MSM) is found in natural foods and used as a dietary supplement due to its anti-oxidant and anti-inflammatory properties. We hypothesized that MSM can induce dentin formation in dental pulp tissue, and this study evaluated the potential of MSM to induce dentin formation. The effect of MSM on mineralized dentin formation was examined using cultured dental pulp cells. Methods: Dental pulp cells were isolated from rat lower incisors using sequential enzymatic treatment and cultured with 25 mmol/l MSM (MSM group) for 14 days. Cells cultured without MSM were examined as a control (Cont) group. Cells were stained with alizarin red (AR). Total RNA was isolated from cells for analysis of Alp, Dentin sialophosphoprotein (Dspp), Bone Gla protein (Bgp), Wnt10a, Wnt6, Axin2, and Runx2 mRNA expression using real-time polymerase chain reaction (PCR). Results: On day 14 of culture, formation of mineralized nodules was detected in cell layers using AR, and the staining intensity in the MSM group was much higher than that in the Cont group throughout the culture period. Compared with the Cont group, MSM also stimulated mRNA expression of the Alp, Dspp, and Bgp genes, which are associated with odontoblast differentiation. Similarly, Wnt10a, Wnt6, and Axin2 expression was also much higher in the MSM group than in the Cont group. Conclusions: These results indicate that MSM activates the Wnt canonical pathway and stimulates odontoblast differentiation of rat dental pulp cells, ultimately resulting in dentin-like nodule formation. The results of the present study suggest an application for MSM as a new biomaterial for vital pulp therapy.