Objective

2

To explore the effect and possible molecular mechanism of

Qinghua Yichang Formula

（清化益肠方， QYF） in treating acute radiation-induced intestinal injury mice via NOD-like receptor thermal protein domain associated protein 3 （NLRP3）.

Methods

2

Sixty C57BL/6J mice were randomly divided into control group， model group， pre-modeling medication group， post-modeling medication group， inhibitor group， and QYF plus inhibitor group， with 10 mice in each group.Except for the control group， the other five groups were irradiated with a single full dose to establish the acute radiation-induced intestinal injury mice model. The pre-modeling medication group and the QYF plus inhibitor group were continuously given 4 g/ml of QYF decoction by gavage before modeling， 0.2 ml each ti

me， once a day for 7 days. The post-modeling medication group， pre-modeling medication group and QYF plus inhibitor group were given 4 g/ml of QYF decoction for 14 days after modeling. The control group， model group and inhibitor group were given 0.2 ml of normal saline once a day for 14 consecutive days. Two hours after irradiation， the inhibitor group and the QYF plus inhibitor group were given an intraperitoneal injection of 0.2 ml of the NLRP3 inhibitor MCC950 （concentration： 10 mg/kg）， once every two days. To observe the pathological changes in intestinal tissues， hematoxylin-eosin （HE） staining was used. Western blotting and RT-qPCR were used to detect the protein and mRNA expression levels of NLRP3 in intestinal tissues. Immunohistochemistry was used to detect the expression level of NLRP3， Caspase-1 and GSDMD in intestinal tissues. The proportion of CD4

+

and CD8

+

T cells in the spleens of mice were detected by flow cytometry. ELISA was used to determine the levels of IFN-γ， IL-18， and IL-1β in mice serum.

Results

2

HE staining showed no lesions in the intestinal tissue of mice in the control group. The mice in the model group had shortened intestinal villi， thinned mucosal layers， multifocal mucosal necrosis in the lamina propria， and local neutrophil infiltration. The pathological damage of intestinal tissue of mice in each medication group was improved to varied degrees， among which the QYF plus inhibitor group showed most obvious improvement. Compared to those in the control group， the protein and mRNA expression levels of NLRP3 in the intestinal tissue of mice in the model group significantly increased， with higher NLRP3， Caspase-1， and GSDMD protein expression in the intestinal tissue， increased proportion of CD4

+

T cells in spleen， decreased proportion of CD8

+

T cells， and increased levels of IFN-γ， IL-18 and IL-1β in serum （

P

＜0.05）. Compared to those in the model group， the above indicators in the other medica

tion groups were all improved （

P

＜0.05）.The NLRP3， Caspase-1， and GSDMD proteins in the pre-modeling medication group were lower than those in the post-modeling medication group （

P

＜0.05）； and the NLRP3 mRNA level in the QYF plus inhibitor group was lower than that in the inhibitor group （

P

＜0.05）.

Conclusion

2

QYF may play a role in preventing and treating acute radiation-induced intestinal injury by inhibiting the expression of NLRP3.