Animal model of radiogenic bone damage to study mandibular osteoradionecrosis.
OBJECTIVE
The objective of the study was to create an animal model to study mandibular osteoradionecrosis (ORN) using high-dose rate (HDR) brachytherapy.


METHODS
Ten Sprague-Dawley male rats were used in this study. Six rats received a single dose of 30 Gy using an HDR remote afterloading machine via a brachytherapy catheter placed along the left hemimandible. The remaining 4 rats served as controls with catheter placement without radiation (sham). On the day following irradiation or sham, all 3 left mandibular molars were atraumatically extracted. Twenty-eight days after irradiation, mandibles were examined using nondecalcified histology with sequential fluorochrome labeling, decalcified histology, and micro-computed tomography scanning.


RESULTS
Irradiated rats demonstrated exposed bone at the extraction sockets, whereas the control animals had complete mucosalization. Alopecia was also seen in the irradiated group. Both histologic and radiologic analyses of the mandible specimens demonstrated a reduction in bone formation in the radiated mandibles as compared with controls.


CONCLUSIONS
Our HDR brachytherapy model incorporating postradiation dental extractions has successfully demonstrated reproducible radiogenic mandibular bone damage analogous to the clinical ORN. Although clinical criteria continue to be used today in describing ORN, this model can serve as a platform for future studies to define ORN and delineate its pathogenesis.
Cohen
Marc
M
Division of Head and Neck Surgery, David Geffen School of Medicine at UCLA, University of California-Los Angeles, 10833 LeConte Avenue, Los Angeles, CA 90095, USA.
Nishimura
Ichiro
I
Tamplen
Matthew
M
Hokugo
Akishige
A
Beumer
John
J
Steinberg
Michael L
ML
Suh
Jeffrey D
JD
Abemayor
Elliot
E
Nabili
Vishad
V
D000818:Animals; D008297:Male; D008334:Mandible; D010025:Osteoradionecrosis / Q000175:diagnosis*; D011833:Radiation Injuries, Experimental / Q000473:pathology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D055114:X-Ray Microtomography / Q000379:methods*