Biodentine™ reduces TNF-α induced TRPA1 expression in odontoblasts

Objectives: Members of the transient receptor potential (TRP) family of ion channels have emerged as important cellular sensors. Amongst the TRP channels, TRPA1 plays a central role in nociception, and is considered the gate keeper of inflammation. TRPA1 has previously been identified in human odontoblasts and has been suggested to mediate odontoblast sensory function. Biodentine^™ is a calcium silicate cement with promising regenerative potential and is proposed for use in pulp capping. Emerging clinical observations after Biodentine^™ application as a restorative material have shown absence of post-operative sensitivity and pain relief effect in cases of symptomatic pulpitis. However the mechanism by which Biodentine^™ induces this pain relief effect is not known
Objectives: To investigate the effect of Biodentine^™ on cytokine-induced TRPA1 expression and function in odontoblasts
Methods: Odontoblasts were differentiated form dental pulp stem cells grown in osteogenic media. TRPA1 expression was determined with immunohistochemistry, qPCR and Western blotting in dental pulp and odontoblasts. The functionality of the channel was confirmed by ratiometric calcium imaging
Results: Immunohistochemistry showed TRPA1 is expressed in odontoblasts and staining intensity was increased in the odontoblast layer of carious compared to intact teeth. In vitro simulation of caries induced inflammation, by treatment of odontoblasts with TNFα, confirmed TRPA1 up regulation at gene and protein level. Calcium imaging confirmed increased channel activity following TNFα treatment. On the other hand treatment with Biodentine^™ significantly reduced TNFα-induced TRPA1 expression while Biodntine^™ was shown to have no effect on basal expression or activity of the channel.
Conclusions: Modulation of TRPA1 expression and activity in odontoblasts may provide an explanation for the anti-inflammatory and pain relief effects of Biodentine^™ observed in the clinic.