ESTRO 2024 - Abstract Book

S5305 ESTRO 2024 4. Girst, S. et al. Proton Minibeam Radiation Therapy Reduces Side Effects in an In Vivo Mouse Ear Model. International Journal of Radiation Oncology*Biology*Physics 95, 234–241 (2016). Radiobiology - Normal tissue radiobiology

5. Lamirault, C. et al. Short and long-term evaluation of the impact of proton minibeam radiation therapy on motor, emotional and cognitive functions. Sci Rep 10, 13511 (2020).

6. Reaz, F., Sitarz, M. K., Traneus, E. & Bassler, N. Parameters for proton minibeam radiotherapy using a clinical scanning beam system. Acta Oncologica 0, 1–5 (2023).

7. Singers Sørensen, B. et al. In vivo validation and tissue sparing factor for acute damage of pencil beam scanning proton FLASH. Radiotherapy and Oncology 167, 109–115 (2022).

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Digital Poster

Radiation induced intestinal resident macrophage turnover is regulated by microbiota

Zihao Wang 1 , Jie Xiao 1 , Jie Yao 2 , Minmin Cao 3 , Binghua Xiang 1 , Dongmei Hu 1 , Wenjun Liao 4 , Shichuan Zhang 4 , Jinyi Lang 4 , Yiling Wang 5 , Yue Zhao 5 1 University of Electronic Science and Technology of China, School of Medicine, Chengdu, China. 2 Sichuan Clinical Research Center for Cancer, Sichuan Cancer Hospital & Institute, Sichuan Cancer Center, Affiliated Cancer Hospital of University of Electronic Science and Technology of China, Basic Research Center, Chengdu, China. 3 Chengdu University of Traditional Chinese Medicine, School of Basic Medical Sciences, Chengdu, China. 4 Sichuan Clinical Research Center for Cancer, Sichuan Cancer Hospital & Institute, Sichuan Cancer Center, Affiliated Cancer Hospital of University of Electronic Science and Technology of China, Department of Radiation Oncology, Radiation Oncology Key Laboratory of Sichuan Province,, Chengdu, China. 5 Sichuan Clinical Research Center for Cancer, Sichuan Cancer Hospital & Institute, Sichuan Cancer Center, Affiliated Cancer Hospital of University of Electronic Science and Technology of China, Department of Radiation Oncology, Radiation Oncology Key Laboratory of Sichuan Province, Chengdu, China

Purpose/Objective:

Intestinal resident CX3CR1 + macrophages are derived from embryos and replenished from peripheral circulating monocytes through a "monocyte waterfall" process depending on CCL2/CCR2 axis. The turnover kinetics and function of intestinal resident macrophage subpopulations during radiation and the underlying mechanisms remains poorly defined. Herein, we used genetic modified mouse Ccr2 RFP/+ Cx3cr1 GFP/+ (R2X3), Ccr2 RFP/RFP Cx3cr1 +/+ (R2-KO) and Ccr2 +/+ Cx3cr1 GFP/GFP (X3-KO) mice were used for cell tracking and to dissect chemokine receptor CCR2 and CX3CR1 function in murine radiation enteritis model.

Material/Methods:

Mice were exposed to abdominal radiation of 13 Gy to induce radiation enteritis. Number of crypts, epithelial thickness and intestine length were compared among groups (R2X3, R2-KO and X3-KO). Lamina propria immune cells were analyzed by flowcytometry. broad-spectrum antibiotics model (Abx model: ampicilin, neomycin, vancomycin and metronidazole) were used to investigate the functions of microbiota in regulating radiation enteritis.