Topical Suramin Diminishes Radiation-induced Oral Mucositis

Objectives: Oral mucositis (OM) is a painful ulceration of the oral and is the most common debilitating side effect of radiation treatment. To date, there is no therapy to prevent or reduce the severity and duration of radiation-induced oral mucositis. Suramin, a polysulfonated naphthyl-urea, was originally designed and used as a treatment for African trypanosomiasis, but has also been shown to enhance wound healing and possess antineoplastic activity. The objective of this study was to evaluate the potential of suramin to prevent radiation-induced OM.

Methods: The head and neck region of six-week-old male and female C57BL/6J mice (4-5 mice/group/sex) were exposed to collimated fractionated radiation (8 Gy on 5 consecutive days). Topically applied suramin (50mg/ml solution) was applied on day 1 of radiation by intraoral swab and twice daily throughout the experimental period. On day 7, all mice were euthanized and tongues were assessed for development and extent of oral mucositis ulceration on the dorsal surface of the tongue using 1% toluidine blue. Epithelial erosion and ulceration were visible as a deep blue color and ulceration area was measured using NIH Image J software. Histopathological grading (0-4 scale) using an established scale was used to assess OM staging and epithelial thinning.

Results: When applied topically, suramin reduced the extent and severity of oral mucositis as measured by the area of toluidine blue stained on the tongue dorsum by ~50% (p<0.05; unpaired Student’s t-test) and the extent and severity of histopathological scoring of OM by ~30% (p<0.001; 2-way ANOVA).

Conclusions: This proof-of-concept study provides evidence that suramin may be clinically useful to prevent oral radiation-induced oral mucositis.