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Objective(s): Acute lung injury (ALI) is a common comorbidity in patients with sepsis, and finding drugs that can effectively reduce its mortality is a hot spot in current research. The purpose of this study is to explore the protective mechanism of N-acetylcysteine (NAC) on ALI in septic rats.Materials and Methods: We used NAC to intervene in septic rats to evaluate the plasma inflammatory factors and lung tissue pathological damage. Biochemical methods were used to determine the levels of oxidases in lung tissue, the expression of inducible nitric oxide synthase (iNOS) and endothelial nitric oxide synthase (eNOS) proteins, and observed lung tissue cell apoptosis.Results: NAC pretreatment decreased the mortality of septic rats, improved lung tissue pathological damage, reduced the levels of tumor necrosis factor-α, interleukin-1β, interleukin-6, interleukin-8, and malondialdehyde, and increased activity of superoxide dismutase, glutathione peroxidase, and catalase. Moreover, NAC pretreatment significantly decreased iNOS protein expression and increased eNOS protein expression in lung tissue. Meanwhile, NAC significantly decreased the number of apoptosis and the levels of Bax and Caspase-3 mRNA and increased the level of Bcl-2 mRNA in the lung tissue of septic rats. Conclusion: NAC protects ALI in septic rats by inhibiting inflammation, oxidative stress, and apoptosis.

Objective(s): To explore the regulation mechanism of Sirtuin 3 (SIRT3) on the mitochondrial function and apoptosis of acute kidney injury (AKI) in septic mice.Materials and Methods: The sepsis-induced AKI model was constructed in the wild-type and SIRT3 knockout (KO) mice, and the levels of serum creatinine (Scr) and plasma kidney injury molecule 1 (pKIM-1) in mice were detected by ELISA. The mitochondrial damage of kidney tubular epithelial cells (KTEC) was observed by electron microscopy, the apoptosis of KTEC was detected by TUNEL assay, and the mRNA levels of SIRT3, Bax, Caspase-3, and Bcl-2 were detected by RT-qPCR.Results: SIRT3 KO caused increased expression of Scr, pKIM-1, and inducible nitric oxide synthase protein in the kidneys of septic mice, and decreased the levels of superoxide dismutase, catalase, and mitochondrial complex enzymes I/II/III/IV. SIRT3 deficiency exacerbated histopathological and mitochondrial damage to the proximal tubules of the kidney. In addition, SIRT3 KO resulted in a significantly increased apoptosis of KTEC, increased the mRNA levels of Bax and Caspase-3, and decreased the mRNA levels of Bcl-2. Conclusion: Our study suggests that SIRT3 deficiency promotes sepsis-induced AKI via increasing oxidative stress, mitochondrial dysfunction, and inducing apoptosis.

Objective(s): To investigate the protective effect of N-acetylcysteine (NAC) on septic acute kidney injury (SAKI) via regulating Sirtuin3 (SIRT3)-mediated mitochondrial dysfunction and apoptosis. Materials and Methods: By constructing SIRT3 knockout mice and culturing kidney tubular epithelial cells (KTECs), we assessed the changes of renal function and detected the protein expression of adenine nucleotide translocator (ANT), cyclophilin (CypD) and voltage-dependent anion channel (VDAC) using western-blotting, and simultaneously detected toll-like receptor 4 (TLR4), inhibitor of kappa B kinase (IKKβ), inhibitor of Kappa Bα (IκBα), and p65 protein expression. We observed mitochondrial damage of KTECs using a transmission electron microscope and assessed apoptosis by TdT-mediated dUTP Nick-End Labeling and flow cytometry. Results: SIRT3 deficiency led to the deterioration of renal function, and caused a significant increase in inducible nitric oxide synthase production, a decrease in mitochondrial volume, up-regulation of TLR4, IκBα, IKKβ, and p65 proteins, and up-regulation of ANT, CypD and VDAC proteins. However, NAC significantly improved renal function and down-regulated the expression of TLR4, IκBα, IKKβ, and p65 proteins. Furthermore, SIRT3 deficiency led to a significant increase in KTEC apoptosis, while NAC up-regulated the expression of SIRT3 and inhibited apoptosis. Conclusion: NAC has a significant protective effect on SAKI by inhibiting SIRT3-mediated mitochondrial dysfunction and apoptosis of KTECs. [ABSTRACT FROM AUTHOR]

Objective(s): We aimed to study the effect of S-nitroso glutathione (SNG) on acute kidney injury (AKI) in septic rats by regulating nucleotide oligomerization domain-like receptor protein 3 (NLRP3). Materials and Methods: Sprague Dawley rats were used to construct the AKI model, and biochemical methods were used to detect the levels of inflammatory factors and anti-oxidant enzymes in renal tissue. We observed the ultrastructural changes of renal tissue by transmission electron microscopy and detected the protein and mRNA levels of NLRP3, apoptosis-associated speck-like protein containing a caspase recruitment domain foci (ASC) and caspase-1 by western-blotting and RT-qPCR. Results: Cecal ligation and puncture induced renal tubular epithelial tissue damage in septic rats, resulting in decreased renal function, increased levels of inflammation and decreased levels of antioxidant enzymes in renal tissue, and aggravated mitochondrial damage, significantly decreased mitochondrial density and enzyme complex I/II/III/IV levels (all P<0.001), and increased the protein and mRNA expression of NLRP3, ASC, and caspase-1 (all P<0.001). However, after pretreatment with SNG, the pathological damage of renal tubular epithelial tissue was reduced, the renal function was improved, the level of inflammation in renal tissue decreased and the level of anti-oxidant enzymes increased, the density of mitochondria and the level of enzyme complex I/II/III/IV were significantly increased (all P<0.001), meanwhile the protein and mRNA levels of NLRP3, ASC, and caspase-1 were all decreased significantly (all P<0.05). Conclusion:: SNG protects AKI in septic rats by inhibiting NLRP3 inflammasome activation. [ABSTRACT FROM AUTHOR]