Mechanism of Buzhong Yiqitang Intervening in Pyroptosis of AIT in NOD.H-2h4 Mice Based on NLRP3/Caspase-1/GSDMD Pathway / 中国实验方剂学杂志

ABSTRACT

ObjectiveTo explore the mechanism of Buzhong Yiqitang on pyroptosis in autoimmune thyroiditis （AIT） mice based on the NOD-like receptor hot protein domain related protein 3 （NLRP3）/cysteinyl aspartate specific proteinase-1（Caspase-1）/Gasdermin D （GSDMD） pathway. MethodSixty NOD.H-2h4 mice were divided into normal group， model group， low， medium， and high dose groups （4.10， 8.19， 16.38 g·kg-1）of Buzhong Yiqitang， and selenium yeast tablet group （0.26 mg·kg-1）， with 10 mice in each group. Except for the normal group， all other groups were given 0.05% NaI by gavage for eight weeks to establish a model and then received the drug treatment for eight weeks. The serum levels of thyroid peroxidase antibody （TPO-Ab） and thyroglobulin antibody （TgAb） were detected using enzyme-linked immunosorbent assay （ELISA） method. Hematoxylin-eosin （HE） staining was used to observe the pathological changes in mouse thyroid tissue. The immunohistochemical method was used to detect the protein expression of NLRP3， Caspase-1， interleukin-1β （IL-1β）， and interleukin-18 （IL-18）. Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） was used to detect the mRNA expression of NLRP3， Caspase-1， IL-1β， and IL-18. Western blot was used to detect the levels of pyroptosis-related proteins in thyroid tissue. ResultCompared with the normal group， the serum levels of TPO-Ab and TgAb in the model group were significantly increased （P<0.01）. Thyroid follicles either increased in a cubic shape or were damaged and atrophied， with a large number of lymphocytes infiltrating around the follicles. Compared with the model group， the levels of TPO-Ab and TgAb in other groups were significantly reduced （P<0.01）， and the morphology and structure of follicles were improved. The degree of lymphocyte infiltration was reduced. Among them， the medium dose group of Buzhong Yiqitang had the most significant reduction and improvement effect. Compared with the normal group， the positive products and mRNA expression of NLRP3， Caspase-1， IL-1β， and IL-18 proteins in the thyroid tissue of the model group significantly increased （P<0.01）， and the protein expression levels of NLRP3， cleaved Caspase-1， IL-1β， IL-18， and GSDMD-N were significantly increased （P<0.05， P<0.01）. Compared with the model group， the positive products and mRNA expression of NLRP3， Caspase-1， IL-1β， and IL-18 proteins in other groups were significantly reduced （P<0.05， P<0.01）， with the most significant reduction effect in the medium dose group of Buzhong Yiqitang. The protein expression levels of NLRP3， cleaved Caspase-1， IL-1β， IL-18， and GSDMD-N were significantly reduced （P<0.05， P<0.01）. ConclusionBuzhong Yiqitang can improve AIT， and its mechanism may be achieved by regulating the NLRP3/Caspase-1/GSDMD signaling pathway to inhibit pyroptosis.