RANKL inhibition induces osteonecrosis of the jaw-like lesions in mice
Objective: Drug-induced osteonecrosis of the jaw (ONJ), clinically defined as exposed necrotic bone with delayed oral mucosal healing for at least 8 weeks after dental-related traumas, is a devastating side effect in the patients undergoing long-term treatment with bisphosphonates (BPs) and denosumab (Dmab) for their bone-associated diseases. Although there are several animal models for BP-related ONJ (BRONJ), there are no animal models for Dmab-related ONJ (DRONJ). Here, we aimed to establish the mouse model for DRONJ.
Method: Eight weeks old female C57BL/6 mice (n=20 per group) were intravenously injected with 250 µg of anti-mouse RANKL or anti-rat IgG antibodies (Ab) biweekly for 4 weeks. At week 1, the maxillary first molar was extracted, and at week 4, the mice were sacrificed to obtain femurs to evaluate bone architectures, maxillae to analyze for the microCT and histology, and blood to examine amount of TRAP 5b in sera. The sectioned slides were stained for tartrate-resistant acid phosphatase (TRAP)+ osteoclasts, K14+ keratinocytes, and CD31+ endothelial cells. Masson’s Trichrome staining was also used to evaluated for collagen.
Result: Anti-RANKL Ab treatment caused improved bone architectures but exhibited delayed wound healing. Histological analysis revealed 50% of the mice treated with anti-RANKL Ab developed ONJ-like lesions as determined by increased numbers of empty lacunae (7.7±3.7 vs. 80.9±31.7 #/mm2) and necrotic bone (0.2±0.3 vs. 13.2±5.0%). TRAP staining and TRAP 5b ELISA assay revealed complete abrogation of osteoclasts and their markers in the serum. Immunohistochemical (IHC) staining with K14 and CD31 showed breached oral mucosal epithelium but increased vasculatures, respectively. Masson’s Trichrome staining showed the lack of connective tissues at the denuded bone areas.
Conclusion: ONJ-like lesions in anti-RANKL Ab-treated mice is associated with the bone necrosis and impaired oral mucosal wound healing. Our newly established mouse model for DRONJ would be instrumental in studying the pathophysiology of drug-induced ONJ.
Division: IADR/AADR/CADR General Session
Meeting:2013 IADR/AADR/CADR General Session (Seattle, Washington) Location: Seattle, Washington
Year: 2013 Final Presentation ID:67 Abstract Category|Abstract Category(s):Mineralized Tissue
Authors
Williams, Drake
( University of California - Los Angeles, Los Angeles, CA, USA
)
Kang, Mo
( University of California - Los Angeles, Los Angeles, CA, USA
)
Park, No-hee
( University of California - Los Angeles, Los Angeles, CA, USA
)
Kim, Reuben
( University of California - Los Angeles, Los Angeles, CA, USA
)
Lee, Cindy
( University of California - Los Angeles, Los Angeles, CA, USA
)
Kim, Terresa
( University of California - Los Angeles, Los Angeles, CA, USA
)
Wu, Hongkun
( Sichuan University, Sichuan, N/A, China
)
Yagita, Hideo
( Juntendo University, Tokyo, N/A, Japan
)
Park, Sil
( University of California - Los Angeles, Los Angeles, CA, USA
)
Yang, Paul
( University of California - Los Angeles, Los Angeles, CA, USA
)
Shi, Songtao
( University of Southern California, Los Angeles, CA, USA
)
Shin, Ki-hyuk
( University of California - Los Angeles, Los Angeles, CA, USA
)