Supernumerary Incisors in CB6F1 Mice Conditioned with Chemotherapy and Total Body Irradiation before Bone Marrow Transplantation

Abstract

Multiple adult female CB6F1 mice presented with supernumerary incisors after preconditioning with chemotherapy and total body irradiation for bone marrow transplantation (BMT). Mice received nonmyeloablative total body irradiation (3 Gy) and either cyclophosphamide or bendamustine, followed by BMT and posttransplantation cyclophosphamide or bendamustine. Here we describe the clinical presentation, μCT findings, and histopathologic evaluation of the affected mice. These analyses confirmed the gross diagnosis and revealed details of the abnormal tooth morphology. We surmise that the combination of total body irradiation and chemotherapy resulted in the abnormal formation of supernumerary incisors. Supernumerary teeth should be considered as a potential confounding factor in tracking weight loss after BMT. These conditions can be managed to allow animals to reach their intended scientific endpoint.

Figure 1.

Supernumerary lower incisors in mouse 1.

Figure 2.

μCT image of mouse 1.

Figure 3.

Unilateral cross-section through the mandible showing an abnormal supernumerary tooth (arrow) medial to the normal mandibular incisor. As compared with the normal incisor, the supernumerary incisor has an irregular circumferential border; dental tubules (clear spaces within the incisor) are less frequent and poorly organized; and mineralization (deep basophilic staining) is present. Hematoxylin and eosin stain; magnification, 10×.