Supplementary Material for: Induction of Radiodermatitis in Nude Mouse Model using Gamma Irradiator IBL 637

Introduction: Acute radiodermatitis is a common, though severe, side effect of radiotherapy against cancer that may lead to an interruption or even abortion of the radiotherapy. Mouse models provide an excellent tool to study pathomechanisms of a radiation-induced dermatitis as well as to test and develop novel innovative treatment strategies. Objective: The aim of this study is to provide an overview of different mouse models and irradiation devices that have been used so far and to describe the process of the induction of a radiation dermatitis in an immune proficient nude mouse model (SKH1-Hrhr) using a IBL 637 Cesium-137γ-ray machine. Methods: This process includes the construction of a radiation shielding chamber, restricting the radiation to the right hind leg of the mouse, a dosimetry and a dose finding study to identify the appropriate irradiation dose to induce a moderate radiation dermatitis. Results: A radiation shielding chamber was successfully constructed allowing selective irradiation of the right hind leg. A moderate radiodermatitis is induced with irradiation doses in the range of 60 – 70 Gy under the here described conditions. Symptoms peak about eight days after irradiation and decrease relatively quickly thereafter. Histological analyses confirmed typical signs of inflammation. Conclusion: This study describes for the first time a protocol to induce a moderate radiodermatitis in the nude mouse model SKH1-Hrhr using a IBL 637 gamma irradiator. This protocol will allow researchers to study novel treatment strategies to alleviate the burden of a radiodermatitis as a side effect of cancer treatment.