Mechanism of Huanglian Wendan Decoction in intervening IGT IR based on liver cell pyroptosis

Abstract

To investigate the mechanism of Huanglian Wendan Decoction in intervening impaired glucose tolerance( IGT) rat insulin resistance( IR) based on the pyroptosis pathway of liver cells. The IGT rat model was established by high-fat diet( 20 weeks) combined with high temperature,humidity environment and inactive lifestyle. The experiment was divided into blank group,model group,metformin hydrochloride group( positive group)( 0. 05 g·kg~(-1)·d~(-1)) and Huanglian Wendan Decoction group( 7. 8 g·kg~(-1)·d~(-1)). After continuous intragastric administration for 4 weeks,the body weight,body length and abdominal circumferences of all the rats were measured,the Lee' s obesity indexes was calculated,and the levels of fasting plasma glucose( FPG) and 2-hour plasma glucose( 2 hPG) in each group were measured. Serum insulin levels( FINS) and tumour necrosis factor-α( TNF-α) levels were detected by ELISA,and insulin sensitivity index( ISI) and insulin resistance index( IRI) values were calculated. The expressions of cysteinyl aspartate specific proteinase-1( caspase-1),gasdermin D( GSDMD),interleukin-1β( IL-1β) and interleukin-18( IL-18) m RNA and proteins in liver tissues were detected by Real-time PCR and Western blot. Immunofluorescence was used to detect the expressions of caspase-1 and GSDMD protein in liver tissues. Huanglian Wendan Decoction could effectively reduce the weight of model rats,improve abdominal obesity,FINS,IRI and ISI indexes and correct 2 hPG levels. Compared with blank group,TNF-α levels in serum and caspase-1,GSDMD,IL-1β and IL-18 expressions in liver tissue of model control group were increased significantly. Huanglian Wendan Decoction could effectively reduce TNF-α level in serum,regulate the expressions of caspase-1,GSDMD,IL-1β and IL-18 genes and proteins in liver tissues of IGT rats. The above results showed that the occurrence and development of " obesity-IR-abnormal glucose metabolism-type 2 diabetes mellitus" was closely related to inflammatory response and the classical pyroptosis pathway mediated by caspase-1/GSDMD. The mechanism of Huanglian Wendan Decoction in improving IR may be correlated with reduction of the level of inflammatory factors and the alleviation of the state of pyroptosis,and thus reverse the course of IGT.