Abstract:This paper examined the impact and mechanism of aqueous extract of Puerariae thomsonii Radix（PTR）on inflammatory damage of islet cells in type 2 diabetic db/db mice. Six db/m mice were selected as the normal group and thirty db/db mice were randomly assigned to the model group，high-，medium-，low-dose PTR aqueous extract groups，and metformin group. Eight weeks after administration，the change in body weight of the mice，the pancreas-to-weight ratio，fasting serum insulin（FINS），fasting blood glucose（FBG），glycosylated serum protein（GSP），and homeostasis model assessment for insulin resistance（HOMA-IR）were determined. Hematoxylin-eosin（HE）staining was used to observe the histopathological changes in pancreas.The protein expressions of tumor necrosis factor-α（TNF-α），nuclear factor kappa-Bp65（NF-κBp65）and interleukin - 18（IL - 18）in islet cells were detected by immunohistochemistry（IHC）. Western blot was conducted to identify the expressions of NOD-like receptor thermoprotein domain 3（NLRP3），apoptosis-associated speck-like protein containing a caspase recruitment domain（ASC），cystein-asparate protease 1（caspase-1），interleukin-1β（IL-1β），and IL-18 in pancreatic tissue，and the expression of NLRP3 was observed by immunofluorescence（IF）. The results showed that，compared with the normal group，the model group had increased body weight，pancreas-to-weight ratio，GSP，FBG，FINS，and HOMA-IR，distorted and inflammatoryinfiltrated islet cells，and unclear boundary between islet cells and acinus cells. There was a significant rise in the protein expressions of TNF-α，NF-κBp65 and IL-18，and the expression of related proteins in pancreatic tissue was markedly elevated. Compared with the conditions in the model group，the body weight，pancreas-toweight ratio，GSP，FBG，and FINS were significantly lowered in the metformin group and PTR aqueous extract groups. Additionally，more islet cells were intact，with obvious boundaries and greatly reduced inflammatory infiltration，and the protein expressions of TNF-α，NF-κBp65，and IL-18 as well as the expression of related proteins in pancreatic tissue dropped in the administration groups compared with those in the model group. In conclusion，PTR aqueous extract can lessen the inflammatory damage of islet cells，decrease insulin resistance，and alleviate the symptoms of type 2 diabetes mellitus. The mechanism may be related to the suppression of the NLRP3 inflammasome pathway and the release of the downstream inflammatory cytokines IL-1β and IL-18.