Lansoprazole and zoledronate delays hard tissue healing of tooth extraction sockets in dexamethasone-treated mice.

Proton pump inhibitors (PPIs) are among the most commonly prescribed medicines for the management of acid-related gastrointestinal diseases. Osteonecrosis of the jaw (ONJ) is a serious adverse event that is associated with the use of antiresorptive and antiangiogenic agents. According to previous clinical reports, the use of PPIs contributes to the pathogenesis of severe ONJ that requires surgery. Here, we investigated the effects of lansoprazole (LP) or LP in combination with zoledronate (ZOL) on ONJ development in mice. C57BL/6J mice were administered ZOL (125 μg/kg intravenously, twice weekly) and/or LP (10 mg/kg intraperitoneally; 3 weeks of 3 consecutive days followed by 1 day off). One week after initiation of the study, the first molar was atraumatically extracted. Concurrently with ZOL administration, dexamethasone (Dex) was administered (5 mg/kg intraperitoneally, twice weekly). Micro-computed tomography and histological evaluation were performed to characterize femoral structures, tooth extraction sockets, and osteonecrosis areas. The results showed that ZOL/Dex significantly increased bone mass compared to saline/Dex, while the simultaneous administration of LP and ZOL/Dex diminished the ZOL-induced enhancement of bone mass. In the alveolar bone around the tooth extraction socket, necrotic bone was significantly increased in the LP/Dex group compared to the saline/Dex group. However, no signs of more severe ONJ-like lesions were observed following combined administration of LP and ZOL/Dex, other than an increase in the number of non-attached TRAP-positive cells. Our findings in a mouse model suggest that LP use can be a risk factor for the development of ONJ.