Investigating the Attenuating Effect of Telmisartan against Radiation-Induced Intestinal Injury Using 18F-FDG micro-PET Imaging

Abstract

Background and Objective The present study was aimed to investigate the ability of 18F-Fluro-deoxy-glucose (18F-FDG) based micro-positron emission tomography (microPET) imaging to evaluate the efficacy of telmisartan, a highly selective angiotensin II receptor antagonist (ARA), in intestinal tissue recovery process after in vivo irradiation. Methods Male Balb/c mice were randomly divided into four groups of control, telmisartan, irradiation, and telmisartan + irradiation. A solution of telmisartan in phosphate buffered saline (PBS) was administered orally at 12 mg/kg body weight for seven consecutive days prior to whole body exposing to a single sub-lethal dose of 5Gy X-rays. The mice were imaged using 18F-FDG microPET at 9 and 30 days post-irradiation. The 18F-FDG uptake in jejunum was determined according to the mean standardized uptake value (SUVmean) index. Tissues were also processed in similar time points for histological analysis. Results The 18F-FDG microPET imaging confirmed efficacy of telmisartan as a potent attenuating agent for ionizing radiation-induced injury of intestine in mice model. The results were also in line with the histological analysis indicating that pre-treatment with telmisartan reduced damage to the villi, crypts, and intestinal mucosa compared to irradiated and non-treated group from day 9 to 30 after irradiation. Conclusion The results revealed that 18F-FDG microPET imaging could be a good candidate to replace time-consuming and invasive biological techniques for screening of radioprotective agents. These findings were also confirmed by histological examinations which indicated that telmisartan can effectively attenuates radiation injury caused by ionizing-irradiation.