The effect a single injection of irinotecan on the development of enamel in the Wistar rats

Objectives: Cancer is the second most frequent cause of death in children. Because the prognosis for childhood malignancies has improved, attention has now focused on long-term consequences of cancer treatment. The immediate effects of chemotherapy on soft tissues have been well described, however there is less information about long-term effects of chemotherapy on the development of dental tissues.
Methods: To test the association between the effect of chemotherapy on enamel development, we examined two groups of rats; one that had received an intraperitoneal dose of 200mg/kg of irinotecan, whereas the other (control) group had received vehicle only. Rats were killed at 6, 48 and 96h following administration of irinotecan or control. The mandibles were dissected out and fixed for histological evaluation and scanned for mineralization defects by MicroCT.
Results: Our results showed structural changes in the ameloblast layer along with a significant reduction in mineralization and thickness of enamel at 96h after chemotherapy.
Conclusions: These data demonstrate that irinotecan induces structural changes in forming enamel that become apparent after treatment.

To our knowledge this is the first report showing changes in ameloblast morphology and function as a result of administration of a chemotherapy drug. This may account for the dental anomalies that have been described in children who have undergone chemotherapy treatment.