Hydrogen peroxide-induced oxidative stress impairs the calcification ability of human dental pulp cells

Abstract The present study was conducted to investigate the effect of hydrogen peroxide (H2O2) as an inducer of oxidative stress on the calcification ability of human dental pulp cells (hDPCs) and the involvement of inositol 1, 4, 5-trisphosphate (IP3). hDPCs were exposed to H2O2. Cell viability and reactive oxygen species (ROS) production were then evaluated. To investigate the effect of H2O2 on the calcification ability of hDPCs, real-time PCR for alkaline phosphatase (ALP) mRNA expression, ALP staining, and Alizarin red staining were performed. Data were compared with those of hDPCs pretreated with 2-aminoethyldiphenylborate (2-APB), which is an IP3 receptor inhibitor. H2O2 at concentrations above 250 µM significantly reduced cell viability. More ROS production occurred in 100 µM H2O2-treated hDPCs than in control cells. H2O2-treated hDPCs showed significant reductions in ALP mRNA expression, ALP activity, and mineralized nodule deposition compared with negative control cells. 2-APB significantly inhibited these reductions. To the best of our knowledge, this is the first study documenting the involvement of IP3 signaling in the calcification ability of human dental pulp cells impaired by H2O2. The results of the present study add molecular insight into internal root resorption and may provide a clue to the development of new therapeutic agents in endodontic therapy.