Radiation-induced acute intestinal injury is a common and serious occurrence following abdominal and pelvic irradiation. The Nod-like receptor protein 3 (NLRP3)-dependant inflammasome and inflammation activation is crucial in this process. In a pre-experimental design of radiation-induced intestinal injury, we found that rosiglitazone inhibited caspase-1 which is a key marker of inflammasome activation. The purpose of the present study was to clarify the inhibitory effect of rosiglitazone on the NLRP3 inflammasome both in vivo and in vitro. Radiation-induced intestinal injury after rosiglitazone treatment, and the expression of interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), caspase-1 and NLRP3 in a radiation-induced intestinal injury model in a rat and macrophages were observed. We found that rosiglitazone ameliorated radiation-induced intestinal injury in rats by suppressing the expression of caspase-1, NLRP3, IL-1β and TNF-α. Treatment with rosiglitazone in vitro reduced the expression of NLRP3, and the NLRP3 activator monosodium urate (MSU) reversed the inhibition of IL-1β and TNF-α by rosiglitazone in macrophages. MSU reversed the protective effect of rosiglitazone on radiation-induced intestinal injury in rats by reversing the rosiglitazone-induced inhibition of IL-1β and TNF-α. Taken together, these findings indicate that the peroxisome proliferator-activated receptor gamma (PPARγ) agonist, rosiglitazone, ameliorates radiation-induced intestine inflammation in rats via inhibiting the induction of the NLRP3-dependent inflammasome in macrophages.
Keywords: Rosiglitazone; TNF-α; inflammasome; inflammation; radiation-induced intestinal injury.
© The Author(s) 2020. Published by Oxford University Press on behalf of The Japanese Radiation Research Society and Japanese Society for Radiation Oncology.