Effects of pentoxifylline and tocopherol on a rat-irradiated jaw model using micro-CT cortical bone analysis

A combination of pentoxifylline (PTX) and tocopherol (TP) is believed to reduce chronic fibrosis and induce bone healing in osteoradionecrosis (ORN) of the mandible, but evidence of its therapeutic effectiveness for cortical bone is lacking. This study was designed to determine the effect of combined PTX and TP (PTX + TP) on mandibular cortical bone remodeling in a rat model of ORN, using micro-CT and histological analysis.

Forty-eight 8-week-old male Sprague-Dawley rats were randomly divided into irradiated (n = 40) and non-irradiated (n = 8) groups. Animals in the irradiated group were divided into four sub-groups, including PTX, TP, PTX + TP, and normal saline. Three weeks after irradiation, mandibular posterior tooth extraction was performed, and animals were sacrificed 7 weeks after irradiation. The mandibles were analyzed using micro-CT and histological evaluation.

The alveolar bone height, cortical bone thickness, cortical bone volume, and total cortical bone surface of the PTX + TP group were significantly greater than those of other irradiated groups (p < 0.05). In 3D reconstructed images, the residual volumes of cortical and cancellous bone were inadequate in the irradiated groups.

We found that a combination of PTX and TP improved quality and quantity of cortical bone in irradiated rat mandibles, thus providing supporting evidence of its utility as a treatment and prophylactic agent in ORN. We observed inadequate volumes of cortical and cancellous bone in ORN mandibles, suggesting that cortical bone could play an important role in further ORN studies.