Objective To construct nucleotide-binding oligomerization domain-like receptor protein 3(NLRP3)knockout mice in order to investigate the effects of NLRP3 knockout on radiation-induced acute pneumonitis and pulmonary fibrosis.Methods Nlrp3+/+and Nlrp3-/-mice were randomly divided into the control group and irradiation group.To induce radiation-caused acute pneumonitis,the control group was exposed to sham irradiation while the irradiation group was exposed to 60Co γ-rays at a dose of 22 Gy at a dose rate of 184.30 R/min.At 14 days post-irradiation,the body weight of each mouse and the wet weight of its lung tissue were measured separately using an analytical balance to calculate the lung coefficient.Quantitative real-time PCR(qPCR)and cytometric bead array(CBA)were used to detect inflammatory responses in lung tissues and serum.Hematoxylin-eosin(HE)staining and F4/80 immunohistochemical staining were used to assess pathological changes and inflammatory cell infiltration in lung tissues.Cysteinyl aspartate specific proteinase-1(caspase-1)activation was analyzed by Western blotting.To establish a model of radiation-induced pulmonary fibrosis,mice were irradiated with 60Co γ-rays at a dose of 18 Gy at a dose rate of 174.67 R/min.At 24 weeks post-irradiation,HE staining and Masson staining were performed to evaluate pulmonary fibrosis.Results NLRP3 knockout inhibited caspase-1 activation,reduced inflammatory responses in lung tissues and serum,suppressed macrophage infiltration,alleviated pulmonary edema,and thereby protected against acute radiation-induced lung injury.Additionally,NLRP3 knockout significantly ameliorated late-stage radiation-induced pulmonary fibrosis.Conclusion NLRP3 knockout can mitigate both early radiation-induced pneumonia and lateradiation-induced pulmonary fibrosis.

Objective To explore the role of dapansutrile(OLT1177)in radiation-induced intestinal injury and the mechanism.Methods C57BL/6J mice were locally irradiated in the abdomen with 60Co to induce a model of radiation-induced intestinal injury.OLT1177 was intraperitoneally injected at a dose of 100 mg/kg 2 hours before irradiation and 6 hours after irradiation before the drug was administered once a day.At 12 hours after irradiation,intestinal tissues were taken for terminal deoxynucleotidyl transferase mediated nick end labeling(TUNEL)staining to detect apoptosis in intestinal tissues.At 4 days after irradiation,mouse serum was collected to detect the levels of inflammatory factors in the serum.Hematoxylin-eosin(HE)stainingwas used for the evaluation of the damage to the intestinal villus structure.Immunohistochemical staining was adopted to detect the changes in crypt proliferation in intestinal tissues.Finally,proteins were isolated from intestinal tissues,and Western blotting was employed to evaluate the activation of nucleotide-binding oligomerization domain-like receptor protein 3(NLRP3)inflammasome.Results After irradiation,the intestinal villi in mice were shortened.Meanwhile,there was a notable declinein the number of cells that were proliferating in the crypts,a surge in the number of apoptotic cells,and a significant spike in the overall inflammatory level.However,administration of OLT1177 inhibited the activation of the NLRP3 inflammasome,reduced apoptosis and pyroptosis,decreased the inflammatory level,and thus improved radiation-induced intestinal injury.Conclusion Administration of OLT1177 can significantly mitigate radiation-induced intestinal injury.

Objective To investigate the therapeutic effect and mechanism of NLRP3 inflammasome inhibitor-dapansutrile(OLT1177)-against acute radiation lung injury.Methods Mice were divided into the control group,OLT1177 injection group,irradiation group,and irradiation+OLT1177 injection group.A single dose of 22 Gy whole-lung 60Co radiation was used to establish a model of acute radiation lung injury.After 6 h of radiation,OLT1177(100mg/kg,once daily)was administered intraperitoneally.After 14 consecutive days of administration,lung tissues were collected and weighed while the lung coefficient was calculated.Hematoxylin-eosin(HE)staining and F4/80 immuno-histochemical staining were used to observe the pathological changes and inflammatory cell infiltration in lung tissues.Real-time quantitative PCR(qPCR)was used to detect the transcription levels of NLRP3,IL-1β,and other mRNAs in lung tissues.Serum cytokines such as TNF-α and IL-6 were measured by cytometric bead array(CBA).The activation of Caspase-1 and IL-18 was detected by Western blotting.Results Radiation caused acute inflammation in the lung tissues of mice,manifested as edema in the lung tissues and destruction of the alveolar structure,increased macrophage infiltration,and elevated expressions of inflammatory genes NLRP3,IL-1β,TNF-α,and IL-6 in the lung tissues and higher serum levels of TNF-α,IL-6.Treatment with OLT1177 significantly improved the above symptoms induced by radiation.OLT1177 inhibited the activation of NLRP3 inflammasome downstream Caspase-1 and IL-18 induced by radiation.Conclusion OLT1177 can significantly alleviate acute radiation lung injury in mice,which may be due to its inhibition of NLRP3 inflammasome activation induced by radiation.