Astragaloside IV Protects Against Diabetic Nephropathy by Inhibiting Pyroptosis Based on NOX4/TXNIP/NLRP3 Pathway

Background and Purpose: Diabetic nephropathy (DN) is a common and severe chronic complication in diabetes mellitus. The purpose of this study was to explore the effect and mechanism of Astragaloside IV (AS-IV) on renal pyroptosis in DN. Experimental Approach: High-fat diet and a small dose of streptozotocin were used to establish the DN model. Rats were treated with vehicle or AS-IV (20-, 40- and 80-mg/kg/day) or valsartan (30mg/kg/day) by gavage. After 12 weeks, animals were euthanized; samples of urine and blood were collected to examine biochemical indicators, advanced glycation end products (AGEs), inflammatory cytokines; kidney tissues were collected for histological observation, TUNEL staining, AGEs, inflammatory cytokines, redox indicators, western blot, and immunohistochemistry. Key Results: Biochemical results showed that AS-IV could significantly alleviate the degree of clinical symptoms and the levels of blood glucose, HbA1C, TG, MDA, AGEs, Interleukin (IL)-1β, and IL-18 while improving the activity of SOD and the secretion and sensitivity of insulin. Histological examination and TUNEL staining indicated that AS-IV attenuated the damage of tissues and cells in the kidney from DN rats. Western blot results revealed that AS-IV relieved the activation of NOX4/TXNIP/NLRP3 pathway and the expression of collagen IV and fibronectin in DN rats. Immunohistochemistry results showed that AS-IV attenuated collagen IV and fibronectin in the kidney from DN rats. Conclusion and Implications: The NOX4/TXNIP/NLRP3 pathway mediated renal pyroptosis could play a crucial role in kidney damage and DN development in rats. Restoration of renal pyroptosis by AS-IV be a potential therapeutic strategy against DN.