Objective To investigate the effect of mitochondria-targeted 2,2,6,6-tetramethylpiperidin-1-oxyl-4-ylamino(mitoTEMPO)on podocyte injury in rat models with chronic kidney disease(CKD)and its related molecular mechanisms.Methods A total of 18 healthy SD rats were randomly divided into control group,model group(CKD group),and mitoTEMPO group,with 6 rats in each group.Renal function was measured by a fully automated biochemical analyzer,and hematoxylin eosin staining was used to detect renal pathological structure.Immunohistochemical staining was used to detect the expression of desmin and podocin in the renal muscle.Transmission electron microscopy was used to detect the ultrastructure of foot cells.Immunofluorescence co staining was used to detect mitochondrial autophagy in podocytes.Real time fluorescence quantitative PCR was used to detect the expression of renal inflammatory factors.Protein immunoblotting was used to detect the expression of Nod-like receptor protein 3(NLRP3)inflammatory bodies,autophagy,and Parkin/PTEN induced putative kinase 1(PINK1)pathway related proteins.Results Compared with the control group,the levels of 24h urinary protein(84.89±8.98 mg/24h vs 5.79±1.39 mg/24h),serum creatinine(Scr)(75.10±10.46 μmol/L vs 38.57±4.89 μmol/L)and blood urea nitrogen(BUN)(8.96±1.07 mmol/L vs 2.73±0.43mmol/L)in CKD group were increased,with significant differences(t=21.322,7.749,13.233,all P＜0.001).The CKD group showed an increase in glomerular volume,mesangial proliferation,and extensive infiltration of inflammatory cells in rats.The foot processes of podocytes in the CKD group were fused,the basement membrane was thickened,and mitochondrial cristae were fractured and vacuolated.Compared with the control group,the positive area of desmin in the CKD group was increased,while the positive area of podocin was decreased,with significant differences(t=9.903,7.651,all P＜0.001).Meanwhile,p62 and desmin were co-localized in the CKD group.In addition,the protein expressions of LC3 Ⅱ/Ⅰ,PINK1 and Parkin in the CKD group were decreased(t=16.984,15.105,11.390),while the expression of IL-1β,TNF-α,NLRP3,cleaved caspase-1 and p62 protein was increased(t=5.700～21.571),and the differences were significant(all P＜0.001),respectively.Compared with CKD group,the levels of 24h urinary protein,Scr and BUN in mitoTEMPO group were decreased,and the differences were significant(t=12.508,4.712,7.338,all P＜).001).Renal pathological damage and podocyte condition of mitoTEMPO group were improved,while mitoTEMPO group showed decreased desmin-positive area and increased podocin-positive area(t=6.649,7.686,all P＜0.001),and colocalization of LC3 and COX Ⅳ was observed in mitoTEMPO group.In addition,the protein expressions ofLC3 Ⅱ/Ⅰ,PINK1 and Parkin in mitoTEMPO group were increased(t=15.481,20.469,5.801),while IL-1 β,TNF-α,NLRP3,cleaved caspase-l,and p62 protein were decreased(t=3.477～9.681),and the differences were significant(all P＜0.001),respectively.Conclusion The mitoTEMPO can be protective against CKD podocyte injury,and the mechanism may be related to the activation of PINK1/parkin pathway-mediated mitochondrial autophagy to inhibit NLRP3 inflammasome.