Modification of oral mucositis by keratinocyte growth factor: single radiation exposure

PURPOSE: The aim was to quantify the effect of recombinant human keratinocyte growth factor (rhKGF) on acute oral mucositis induced by a single radiation dose, simulating accidental radiation exposure. MATERIAL AND METHODS: Tongue epithelium of the C3H/Neu mouse was irradiated with graded single doses of 25 kV X-rays to a 3 x 3 mm2 area in the centre of the lower tongue surface. Acute mucosal ulceration, as a clinically relevant reaction, was used as the quantal endpoint for dose response analyses by probit analysis. As a secondary endpoint the time-course, i.e. time to first diagnosis of ulcer (latent time) and individual ulcer duration, was analysed. KGF was applied before, after or in combination before and after radiation exposure. RESULTS: Administration of KGF in all protocols resulted in a significant reduction of the incidence of oral mucosal ulceration, as illustrated by an increase in iso-effective dose from 10.9 to 24.9 Gy; the corresponding dose-modification factors ranged between 1.7 and 2.3. The effect was most pronounced when KGF was applied after irradiation. In all protocols where KGF was given after irradiation, a significant shortening of the latent time to ulceration from 11 to 6-8 days was observed. CONCLUSIONS: The mechanisms underlying the amelioration of the oral mucosal response to single-dose irradiation remain unclear. However, KGF represents a promising approach for the effective management of acute radiation reactions in oral, gastrointestinal and cutaneous epithelia after radiation exposure.