However, pulpal injuries caused by events, such as trauma and chronic inflammatory processes,

could activate odontoclast differentiation and induce a resorptive process in dentin, ultimately causing the release of these drugs to interact with the pulp tissue.5 Another hypothesis of the action of bisphosphonates on the pulp tissue would be their cytotoxicity at the moment of infusion. Selleck Veliparib However, it is suggested that, the limited drug concentration at the moment of infusion would not be sufficient to produce a cytotoxic effects to the pulp cells.5 Recent studies have shown that bisphosphonates are cytotoxic to different cell types.5, 9, 10 and 11 Therefore, the release of this drug to the pulp tissue could promote cytotoxic effects to the pulp cells, reducing the reparative capacity of this tissue.

In mammalian teeth, odontoblasts are organized in a monolayer that underlies the coronal and root dentin, and thus these peripheral pulp cells would be the first to get in contact with bisphosphonates released from dentin.12 and 13 Therefore, the aim of this study was to evaluate the effects of zoledronic acid (ZOL), a highly potent, heterocyclic nitrogen-containing bisphosphonate, on odontoblast-like MDPC-23 cells by evaluating succinic dehydrogenase (SDH) enzyme production (cell viability – MTT assay), total protein (TP) production, alkaline phosphatase (ALP) GSK2118436 cell line activity, reverse transcriptase polymerase chain reaction (qPCR) for collagen type I (Col-I) and ALP, and morphology (scanning electron microscopy – SEM). The odontoblast-like cells MDPC-23 used in this study were cultivated Low-density-lipoprotein receptor kinase in Dulbecco’s Modified Eagle’s Medium (DMEM; Sigma Aldrich Corp., St. Louis, MO, USA) supplemented with 10% fetal bovine serum (FBS; Gibco, Grand Island, NY, USA) and containing 100 IU/mL penicillin, 100 μg/mL streptomycin

and 2 mmol/L glutamine (Gibco) in an humidified incubator with 5% CO2 and 95% air at 37 °C (Isotemp Fisher Scientific, Pittsburgh, PA, USA). The MDPC-23 cells in DMEM containing 10% FBS were sub-cultured at every 2 days until an adequate number of cells were obtained for the study, and then plated (1.5 × 104 cells/cm2) onto sterile 24-well plates (Costar Corp., Cambridge, MA, USA), which were maintained in the humidified incubator with 5% CO2 and 95% air at 37 °C for 48 h. Three groups were then established: one control group, which received no treatment, and two experimental groups, which were treated with ZOL at concentrations of 1 μM and 5 μM. Zoledronic acid (ZOL) was selected for investigation in the present study because it is a high potent bisphosphonate and, according to recent studies,14 and 15 is one of the most frequently prescribed bisphosphonates. In addition, several workers reported that this nitrogen containing bisphosphonate may cause intense cytotoxic effects in different types of cell cultures, including pulp cells.