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.

Objective: To evaluate the effect of intraperitoneally injected dexmedetomidine on abdominal adhesions in rats and the role of cholinergic anti-inflammatory pathway. Methods: Forty clean-grade healthy adult male Sprague-Dawley rats, weighing 220-250 g, were divided into 4 groups (n = 10 each) using a random number table method: sham operation group (Sham group), abdominal adhesion group (AA group), dexmedetomidine group (DEX group) and dexmedetomidine plus methyllycaconitine group (DEX-M group). The rat model of abdominal adhesions was established by cecal friction method.In Sham group, abdominal cavity was only opened and then sutured.Normal saline 2 ml was injected into the abdominal cavity and tail vein in group AA.In DEX and DEX-M groups, normal saline 2 ml and α7 nicotinic acetylcholine receptor antagonist methyllycaconitine 2.4 μg/g (dissolved in 2 ml normal saline) were injected, respectively, and dexmedetomidine 10 μg/kg (dissolved in 2 ml normal saline) was intraperitoneally injected at the same time.The abdominal incision was opened under anesthesia at 7 days after establishing the model to observe the formation of abdominal adhesion, Phillips method was used for scoring, and enzyme-linked immunosorbent assay was used to determine the transforming growth factor-beta1 (TGF-β1) concentrations in ascites and tumor necrosis factor-alpha (TNF-α) concentrations in serum.The rats were then sacrificed, and the caecum tissue and its contralateral peritoneum and adhesion fibrous strips were obtained for examination of the pathological changes with a light microscope. Results: Compared with group Sham, the abdominal adhesion score and serum TNF-α concentrations were significantly increased in AA and DEX-M groups, and the TGF-β1 concentration in ascites was significantly increased in AA, DEX and DEX-M groups (P<0.05). Compared with group AA, the serum TNF-α concentrations and TGF-β1 concentration in ascites were significantly decreased in group DEX-M, and the abdominal adhesion score was significantly decreased (P<0.05), and the pathological changes of caecum tissue, contralateral peritoneum and adhesion fibrous strips were significantly attenuated in group DEX.Compared with group DEX-M, the serum TNF-α concentrations were significantly increased (P<0.05), no significant change was found in TGF-β1 concentration in ascites (P>0.05), and the pathological changes of caecum tissue, contralateral peritoneum and adhesion fibrous strips were accentuated in group DEX. Conclusion Intraperitoneally injected dexmedetomidine can mitigate abdominal adhesions, and the mechanism is related to activating cholinergic anti-inflammatory pathway and reducing systemic inflammatory response in rats.