Azilsartan Ameliorates Diabetic Kidney Disease Through Modulation of Inflammation, Pyroptosis, and Mitochondrial...

To investigate the protective effects of Azilsartan (AZL) on kidney injury in diabetic nephropathy (DKD) mice and high glucose (HG)-induced mesangial cell damage, and to clarify whether these effects are mediated through the regulation of mitochondrial reactive oxygen species (mtROS) and NLRP3 inflammasome-mediated pyroptosis.

SPF male C57BL/6 mice, aged 6-8 weeks, were adapted for 1 week and randomly divided into a control group and a DKD group. The DKD model was established through right nephrectomy combined with a high-fat diet and intraperitoneal injection of streptozotocin (STZ, 50 mg/kg). After successful modeling, the two groups were further divided into a saline subgroup and an AZL intervention subgroup, with continuous intervention for 8 weeks. In vitro, mesangial cells from mice during the logarithmic growth phase were divided into normal glucose (NG) and HG groups, further setting up saline control and AZL intervention subgroups. MitoQ, a mitochondrial-targeted antioxidant, was used to verify the role of mtROS. Parameters including systolic blood pressure, blood glucose, serum creatinine, and urinary albumin-to-creatinine ratio (UACR) were measured in mice. Kidney pathology was observed by PAS staining. Western blotting was used to detect the expression of NLRP3, cleaved-Caspase1, GSDMD-N, and other pyroptosis-related proteins in kidney tissues and mesangial cells. ELISA was used to measure the concentration of IL-1β in serum and cell supernatants. Mitochondrial morphology, membrane potential, and mtROS levels in mesangial cells were observed using laser confocal microscopy. ATP content in cells was measured by chemiluminescence, and cell injury was assessed by LDH assay.

In vivo, compared to the control group, the DKD+Saline group showed significantly increased systolic blood pressure, blood glucose, serum creatinine, and UACR, with evident mesangial matrix expansion and enhanced activation of the NLRP3 inflammasome and pyroptosis. AZL intervention significantly improved these abnormalities. In vitro, HG induced mitochondrial structural damage, decreased membrane potential, reduced ATP generation, and increased mtROS levels in mesangial cells while also activating NLRP3 inflammasome-mediated pyroptosis. AZL intervention significantly reversed these changes, and MitoQ, by inhibiting mtROS, mimicked the protective effects of AZL.

AZL improves renal function and pathology in DKD mice, potentially through both hemodynamic (blood pressure lowering) and nonhemodynamic mechanisms. In vitro evidence indicates that AZL suppresses HG-induced mesangial cell pyroptosis by inhibiting mtROS generation and NLRP3 inflammasome activation.