Effects of samarium-153-ethylenediaminetetramethylene phosphonate on physeal and articular cartilage in juvenile rabbits

Previous studies have reported that the radiopharmaceutical, 153Samarium-EDTMP is an effective component of multi-modality therapy for treatment of primary bone tumors. Therefore, 153Sm-EDTMP may prove to be an integral component of therapy for treatment of juvenile osteosarcoma. The purpose of this study was to determine the effects of intravenous administration of 153Sm-EDTMP on the developing physeal and articular cartilage of healthy, juvenile rabbits. In this study sixteen healthy 8-week-old male New Zealand white rabbits were assigned to one of two groups: Treatment (n = 12), Control (n = 4). 37 MBq/kg (1 mCi/kg) of 153Samarium-EDTMP was administered to the treatment group. The animals were sacrificed at 16 weeks of age and physeal cartilage of multiple bones was evaluated using histology, immunohistochemistry and histomorphometry. Overall change in length of the radius and tibia between control and treatment groups was calculated and compared. Measurement data were combined for each group and means ± SEM were determined. Significant differences in radial bone growth were present between groups. Histologically, the physes of the treatment group were disrupted and chaotic in appearance. Significant differences in immunoreactivity of collagen Type X and MMP-13 were seen between the groups, as these markers were positively expressed in the zone of hypertrophy of the control rabbits. In conclusion, clinically significant damage to the developing physeal cartilage may occur as the result of intravenous administration of 153Samarium-EDTMP at the dosage studied.