Objective To evaluate the effect of sufentanil postconditioning on the level of cathepsin B in the myocardium during ischemia-reperfusion (I/R) in the rats.Methods Eighteen healthy adult male Sprague-Dawley rats,weighing 250-300 g,were divided into 3 groups (n=6 each) using a random nunber table:shamn operation group (group S),group I/R and sufentanil postconditioning group (group SP).The rats were anesthetized with intraperitoneal 20％ urethane 5 ml/kg.Myocardial I/R was induced by occlusion of the left anterior descending branch of the coronary artery for 30 min followed by 120 min reperfusion.At 5 min before reperfusion,sufentanil 1.0 μg/kg was intravenously injected in group SP,and the equal volume of normal saline was given instead in S and I/R groups.At the end of reperfusion,blood samples from the abdominal aorta were collected for determination of serum cardiac troponin I (cTnI) and creatine kinase-MB (CK-MB) concentrations,and myocardial specimnens were obtained for examination of the ultrastructure of cardiomyocytes (using transmission electron microscopy) and for determination of Beclin1,microtubule-associated protein 1 light chain 3 Ⅱ (LC3 Ⅱ) and cathepsin B expression (by Western blot) and cathepsin B activity (by fluorometric assay).Results Compared with group S,the serum cTnI and CK-MB concentrations were significantly increased,the expression of Beclin-1,LC3 Ⅱ and cathepsin B was up-regulated,and the activity of cathepsin B was enhanced in I/R and SP groups (P＜0.05).Compared with group I/R,the serum cTnI and CK-MB concentrations were significantly decreased,the expression of Beclin-1 and LC3 Ⅱ was down-regulated,the expression of cathepsin B was up-regulated,and the activity of cathepsin B was enhanced (P＜0.05),the pathological changes of myocardial tissues were signifieantly attenuated,and autophagosomes were reduced in group SP.Conclusion The mechanism by which sufentanil postconditioning inhibits cardiomyocyte autophagy during myocardial I/R is probably related to increased expression and activity of cathepsin B in rats.

OBJECTIVE: To evaluate the effect of curcumin on renal mitochondrial oxidative stress, nuclear factor-κB/NOD-like receptor protein 3 (NF-κB/NLRP3) inflammatory body signaling pathway and tissue cell injury in rats with acute respiratory distress syndrome (ARDS). METHODS: A total of 24 specific pathogen free (SPF)-grade healthy male Sprague-Dawley (SD) rats were randomly divided into control group, ARDS model group, and low-dose and high-dose curcumin groups, with 6 rats in each group. The ARDS rat model was reproduced by intratracheal administration of lipopolysaccharide (LPS) at 4 mg/kg via aerosol inhalation. The control group was given 2 mL/kg of normal saline. The low-dose and high-dose curcumin groups were administered 100 mg/kg or 200 mg/kg curcumin by gavage 24 hours after model reproduction, once a day. The control group and ARDS model group were given an equivalent amount of normal saline. After 7 days, blood samples were collected from the inferior vena cava, and the levels of neutrophil gelatinase-associated lipocalin (NGAL) in serum were determined by enzyme-linked immunosorbent assay (ELISA). The rats were sacrificed, and kidney tissues were collected. Reactive oxygen species (ROS) levels were determined by ELISA, superoxide dismutase (SOD) activity was detected using the xanthine oxidase method, and malondialdehyde (MDA) levels were determined by colorimetric method. The protein expressions of hypoxia-inducible factor-1α (HIF-1α), caspase-3, NF-κB p65, and Toll-like receptor 4 (TLR4) were detected by Western blotting. The mRNA expressions of HIF-1α, NLRP3, and interleukin-1β (IL-1β) were detected by reverse transcription-polymerase chain reaction (RT-PCR). Renal cell apoptosis was detected by TdT-mediated dUTP nick end labeling (TUNEL). The morphological changes in renal tubular epithelial cells and mitochondria were observed under a transmission electron microscope. RESULTS: Compared with the control group, the ARDS model group exhibited kidney oxidative stress and inflammatory response, significantly elevated serum levels of kidney injury biomarker NGAL, activated NF-κB/NLRP3 inflammasome signaling pathway, increased kidney tissue cell apoptosis rate, and renal tubular epithelial cell damage and mitochondrial integrity destruction under transmission electron microscopy, indicating successful induction of kidney injury. Following curcumin intervention, the injury to renal tubular epithelial cells and mitochondria in the rats was significantly mitigated, along with a noticeable reduction in oxidative stress, inhibition of the NF-κB/NLRP3 inflammasome signaling pathway, and a significant decrease in kidney tissue cell apoptosis rate, demonstrating a certain dose-dependency. Compared with the ARDS model group, the high-dose curcumin group exhibited significantly reduced serum NGAL levels and kidney tissue MDA and ROS levels [NGAL (μg/L): 13.8±1.7 vs. 29.6±2.7, MDA (nmol/g): 115±18 vs. 300±47, ROS (kU/L): 75±19 vs. 260±15, all P < 0.05], significantly down-regulated protein expressions of HIF-1α, caspase-3, NF-κB p65, and TLR4 in the kidney tissue [HIF-1α protein (HIF-1α/β-actin): 0.515±0.064 vs. 0.888±0.055, caspase-3 protein (caspase-3/β-actin): 0.549±0.105 vs. 0.958±0.054, NF-κB p65 protein (NF-κB p65/β-actin): 0.428±0.166 vs. 0.900±0.059, TLR4 protein (TLR4/β-actin): 0.683±0.048 vs. 1.093±0.097, all P < 0.05], and significantly down-regulated mRNA expressions of HIF-1α, NLRP3, and IL-1β [HIF-1α mRNA (2^-ΔΔCt): 2.90±0.39 vs. 9.49±1.87, NLRP3 mRNA (2^-ΔΔCt): 2.07±0.21 vs. 6.13±1.32, IL-1β mRNA (2^-ΔΔCt): 1.43±0.24 vs. 3.95±0.51, all P < 0.05], and significantly decreased kidney tissue cell apoptosis rate [(4.36±0.92)% vs. (27.75±8.31)%, P < 0.05], and significantly increased SOD activity (kU/g: 648±34 vs. 430±47, P < 0.05). CONCLUSIONS Curcumin can alleviate kidney injury in ARDS rats, and its mechanism may be related to the increasing in SOD activity, reduction of oxidative stress, and inhibition of the activation of the NF-κB/NLRP3 inflammasome signaling pathway.
Male ; Rats ; Animals ; Rats, Sprague-Dawley ; NF-kappa B ; Actins ; Caspase 3 ; Curcumin ; Lipocalin-2 ; Toll-Like Receptor 4 ; Inflammasomes ; NLR Family, Pyrin Domain-Containing 3 Protein ; Reactive Oxygen Species ; Saline Solution ; Kidney ; Superoxide Dismutase