ESTRO 2025 - Abstract Book

S3931

Radiobiology - Normal tissue radiobiology

ESTRO 2025

2593

Digital Poster Endogenous hydrogen sulphide-responsive and depleting polyoxometalates alleviates radiation-induced enteritis Jie Zhou, Chenxi Yang Department of Radiation Oncology, Radiation Oncology Key Laboratory of Sichuan Province, Sichuan Cancer Hospital , Afliated Cancer Hospital of University of Electronic Science and Technology of China, Chengdu, China Purpose/Objective: The prevention and treatment of radiation-induced enteritis are still a challenge in clinic 1,2 . Hydrogen sulfide (H 2 S), an important endogenous gaseous transmitter, plays a bifunctional role in inflammation response. Higher concentrations of H 2 S often acts as a pro-inflammatory agent, whereas low concentrations of H 2 S tends to produce cytoprotective, antioxidant-type responses with anti-inflammatory effects 3 . However, whether and how H 2 S interfere radiation-induced intestinal inflammation remains poorly understood. Herein, we aimed to explore the effects of a novel endogenous H 2 S - responsive and depleting polyoxometalates (Mo-POMs) on radiation-induced intestinal damage. Material/Methods: MoO x nanoparticles were prepared by ultrasonic stripping and H 2 O 2 oxidation of Mo 2 C. The UV-vis absorption spectroscopy, X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy were employed to verify that the MoO X nanoparticles can form Mo-POMs upon reaction with H 2 S at room temperature easily. The ability of MoO x nanoparticles to consume H 2 S was detected by WSP-5 probe. The intracellular reactive oxygen species (ROS) levels were monitored with 2,7-dichlor-odihydrofluorescein diacetate (DCFH-DA). The radioprotective effects of Mo-POMs on intestinal epithelial cells were analyzed by live/dead cell assays, cell counting kit -8, and apoptosis detection. By constructing a radiation-induced enteritis model, we also analyze the effect of Mo-POMs (generated by the reaction of MoO X nanoparticles with endogenous H 2 S) on radiation-induced intestinal injury in vivo. Results: Firstly, these results of material characterization confirmed that MoO x nanoparticles can form Mo-POMs upon reaction with H 2 S. During the response, part of the Mo 6+ was reduced to Mo 5+ . Furthermore, the IEC-6 cells (Rat small intestinal epithelial crypt cells) pre-treated with L-Cysteine (H 2 S provider) detected by WSP-5 showed significant green fluorescence which could be effectively inhibited by adding MoO x . Then, the results of live/dead cell assays, cell counting kit -8, and apoptosis detection intuitively suggested that the damage caused by X-ray can be significantly minimized by incubating with MoO x . Moreover, compared to the X-ray group, the intensity of green fluorescence(ROS activated DCFH-DA) in the IEC-6 cells treated with MoO x was diminished. Apart from this, we investigated radioprotective efficacy in vivo. Compared to the X-ray group, the MoOx-treated group, possessed faster recovery of body weight, lower disease activity index, and less release of inflammatory cytokines. Meanwhile, MoO x can be eliminated from the body within approximately 24 hours, demonstrating no significant toxic side effects and exhibiting high safety.