Histopathologic grading of oral mucositis.

OBJECTIVE

Oral mucositis is a common adverse effect of cytotoxic chemotherapy and radiation, and it causes debilitating morbidity that may necessitate interruptions in cancer treatment. Animal models of oral mucositis are invaluable tools for testing novel therapeutics, but grading of lesions based on subjective assessments makes conformism between studies difficult. A standardized scoring system that can objectively and reproducibly grade the severity of oral mucositis is critical in comparing and validating efficacies of developing therapeutics.

MATERIALS AND

METHODS

The head region of male Balb/C animals was exposed to collimated radiation delivered as fractions of 8 Gy on three consecutive days, or as a single large dose of 22.5 Gy. The development of oral toxicity was assessed by histologic analysis of the tongue at various days postradiation.

RESULTS

After fractionated radiation, early epithelial atypia of basal cell layer disorganization and nuclear aberrations was evident by day 6. The disease displayed moderate changes of epithelial atrophy and dyskeratosis by day 7.5 with subsequent epithelial breakdown and ulceration by day 9. In contrast, exposure to a single large-dose radiation resulted in bulla formation by day 9 in most animals.

CONCLUSIONS

An oral mucositis grading system based on histopathologic scoring of tissues is proposed.