OBJECTIVES: To investigate the regulatory role of the NLRP3 signaling pathway in hepatocyte pyroptosis in nonalcoholic steatohepatitis (NASH) under hypoxia. METHODS: Twenty-four male C57BL/6 mice were randomized equally into hypoxic control (A), hypoxic NASH model (B), hypoxic NASH+NLRP3 inhibitor (C), and hypoxic NASH+caspase-1 inhibitor (D) groups. In groups B-D, the mice were fed a methionine choline-deficient (MCD) diet under hypoxic conditions (to simulate a 5000 m altitude) for 6 weeks; the mice in groups C and D received intraperitoneal injections of the respective inhibitors every other day. RESULTS: Compared with those in group A, the mice in group B showed significantly elevated serum levels of FBG, TC, TG, ALT and AST, increased liver lipid content, inflammatory cell infiltration and collagen fiber deposition, and enhanced hepatic expressions of NLRP3, caspase-1, IL-1β and GSDMD proteins, with obvious swelling, cristae breakage, vacuolization, and outer membrane disruption of the mitochondria, ribosome loss in the cytoplasm, destruction of the nuclear membrane, and pathological changes of the rough endoplasmic reticulum. Treatment with NLRP3 inhibitor and caspase-1 inhibitor both significantly lowered serum levels of TC, TG, ALT and AST (but without significantly affecting FBG) in the mouse models, and reduced liver lipid content, inflammatory cell infiltration, collagen deposition, and expression levels of NLRP3, caspase-1, GSDMD and IL-1β. The treatments also significantly improved pathological changes in the mitochondria, ribosomes and endoplasmic reticulum in liver tissues of the mice. CONCLUSIONS NLRP3 signaling pathway plays a key role in promoting hepatocyte pyroptosis in NASH mice under hypoxic condition, and inhibiting this pathway can effectively reduce liver inflammation, suggesting its potential as a therapeutic target for NASH treatment.
Animals ; Non-alcoholic Fatty Liver Disease/metabolism* ; NLR Family, Pyrin Domain-Containing 3 Protein/metabolism* ; Pyroptosis ; Mice, Inbred C57BL ; Male ; Hepatocytes/pathology* ; Signal Transduction ; Mice ; Hypoxia/metabolism* ; Caspase 1/metabolism* ; Interleukin-1beta/metabolism* ; Liver/metabolism*

Objective : To investigate the effects of hypoxia , high glucose single factor and hypoxia high glucose compound factors on the pyroptosis of rat glomerular podocytes . Methods : Rat glomerular podocytes were cultured in vitro and randomly divided into control group , high glucose group , hypoxia group and hypoxia high glucose group , EdU method was used to detect the cell proliferation , transmission electron microscope was used to observe the morphology and size changes of nucleus and mitochondria , and Western blot was used to detect pyroptosis related proteins nucleotide⁃binding oligomerization domain⁃like receptor protein 3(NLRP3) , Cysteinyl aspartate specific proteinase⁃1(Caspase⁃1) , gasdermin( GSDMD) and inflammatory factor pro⁃interleukin⁃1β( Pro⁃IL⁃1β) , interleukin(IL) Ⅳ1β , IL⁃18 . The effect of hypoxia and high glucose on the pyroptosis of rat glomerular podocytes was analyzed . Results : EdU results showed that hypoxia and high glucose inhibited the proliferation ability of rat glomerlar podocytes (P < 0. 05) . The results of transmission electron microscopy suggested that hypoxia and high glucose promoted the occurrence of pyroptosis of rat glomerular podocytes . Western blot showed that hypoxia and high glucose promoted pyroptosis of rat glomerular podocytes , and increased the expression of pyroptosis related proteins NLRP3 , Caspase⁃1 and GSDMD , among which the expression of pyroptosis protein increased most significantly in hypoxia and high glucose group (P < 0. 05) . At the same time , it also increased the expression of pro⁃inflammatory factor Pro⁃IL⁃1β , IL⁃1β and IL⁃18 (P < 0. 05) . Conclusion hypoxia and high glucose can induce pyroptosis of rat glomerular podocytes , one of the mechanisms may be through affecting NLRP3 ⁃Caspase⁃1 ⁃GSDMD and its down⁃ stream inflammatory factors .