ACEMANNAN-CONTAINING WOUND DRESSING GEL REDUCES RADIATION-INDUCED SKIN REACTIONS IN C3H MICE

Purpose: To determine (a) whether a wound dressing gel that contains a cemannan extracted from aloe leaves affects the severity of radiation- induced acute skin reactions in C3H mice; (b) if so, whether other com mercially available gels such as a personal lubricating jelly and a he aling ointment have similar effects; and (c) when the wound dressing g el should be applied for maximum effect.Methods and Materials: Male C3 H mice received graded single doses of gamma radiation ranging from 30 to 47.5 Gy to the right leg, In most experiments, the gel was applied daily beginning immediately after irradiation, To determine timing of application for best effect, gel was applied beginning on day -7, 0, or +7 relative to the day of irradiation (day 0) and continuing for 1, 2, 3, 4, or 5 weeks, The right inner thigh of each mouse was scored o n a scale of 0 to 3.5 for severity of radiation reaction from the seve nth to the 35th day after irradiation, Dose-response curves were obtai ned by plotting the percentage of mice that reached or exceeded a give n peak skin reaction as a function of dose, Curves were fitted by legi t analysis and ED(50) values, and 95% confidence limits were obtained. Results: The average peak skin reactions of the wound dressing gel-tr eated mice were lower than those of the untreated mice at all radiatio n doses tested, The ED(50) values for skin reactions of 2.0-2.75 were approximately 7 Gy higher in the wound dressing gel-treated mice. The average peak skin reactions and the ED(50) values for mice treated wit h personal lubricating jelly or healing ointment were similar to irrad iated control values, Reduction in the percentage of mice with skin re actions of 2.5 or more was greatest in the groups that received wound dressing gel for at least 2 weeks beginning immediately after irradiat ion, There was no effect if gel was applied only before irradiation or beginning 1 week after irradiation. Conclusion: Wound dressing gel, b ut not personal lubricating jelly or healing ointment, reduces acute r adiation-induced skin reactions in C3H mice if applied daily for at le ast 2 weeks beginning immediately after irradiation.