S-nitrosoglutathione protects lipopolysaccharide-induced acute kidney injury by inhibiting toll-like receptor 4-nuclear factor-κB signal pathway

Study on the therapeutic effect of glucocorticoids on acute kidney injury in rats exposed to diquat

AIMS

To preliminarily explore, whether glucocorticoids have a therapeutic effect on diquat-induced acute kidney injury in rats.

METHOD

150 Wistar rats were randomly divided into six groups: exposure model group (DQ group), dexamethasone control group (GC group), blank control group (Ctrl group), dexamethasone 2.1 mg/kg dose group (DQ+L-GC group), dexamethasone 4.2 mg/kg dose group (DQ+M-GC group), and dexamethasone 8.4 mg/kg dose group (DQ+H-GC group), with 25 rats in each group. Each group was further divided into five subgroups, 24 h, 3 d, 7 d, 14 d, and 21 d after exposure, according to the feeding time and the course of treatment, with five animals in each subgroup. The rats in DQ, DQ+L-GC, DQ+M-GC, and DQ+H-GC groups were administered 115.5 mg/kg diquat by gavage, respectively. Moreover, 30 min after gavage, rats in DQ+L-GC group, DQ+M-GC group, DQ+H-GC group and GC group were intragastric administered dexamethasone 2.1 mg/kg, 4.2 mg/kg, 8.4 mg/kg and 8.4 mg/kg, respectively. After 7 days, the intraperitoneal injection of dexamethasone was changed to 6.3 mg/kg prednisone by intragastric administration. Subsequently, 7 days later, it was changed to 3.15 mg/kg prednisone by intragastric administration until the end of the experiment on 21 days. After the start of the experiment, changes in the conditions of the rats in each group were observed at a fixed time every day, changes in the body weight of the rats were monitored at the same time, and the death of the rats was recorded at 24 h, 3 d, 7 d, 14 d, and 21 d after exposure. The rats were sacrificed by an intraperitoneal injection of 100 mg/kg sodium pentobarbital overdose. Blood was collected by puncture of the inferior vena cava, used to determine Cr and BUN. The upper segment of the left kidney was collected for histopathological examination. Elisa was used to detect neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1) in the lower segment of left kidney. TLR4, Myd88, and NF-κB were detected in the right kidney.

RESULTS

(1) After exposure, most rats in DQ group, DQ+L-GC group, DQ+M-GC group and DQ+H-GC group showed shortness of breath, oliguria, diarrhea, yellow hair and other symptoms. No symptoms and related signs were observed in Ctrl group and GC group. (2) The weight of rats in the Ctrl group and the GC group increased slowly during the test. the body weight of the rats in the DQ, DQ+L-GC, DQ+M-GC, and DQ+H-GC groups continued to decrease after self-infection. Body weight dropped to the lowest point at approximately 7 d, and gradually increased from 7 d to 21 d. (3) A small amount of capillary congestion in the medulla was observed after 7 days in the GC group. The DQ group showed tubular atrophy, edema of the epithelial cells, and over time, the tubules were seen dilated and became irregular in shape; large amount of capillary congestion was also observed in the renal cortex and medulla. The renal injury in the DQ+L-GC group was less than that in the DQ group. DQ+H-GC group had no obvious injury before 7 d, but more renal tubules were seen in the DQ+H-GC group from 7 d to 14 d. (4) Compared with the DQ group, there was no difference before 14 d, and at 14 d-21 d, DQ+L-GC group, DQ+M-GC group, DQ+H-GC group all had different degrees of decline. NGAL content: Compared with the DQ group, the content of NGAL and KIM-1 in kidney tissue of the DQ+L-GC, DQ+M-GC, and DQ+H-GC groups decreased compared with the DQ group at each time node. (5) Compared with the Ctrl group, the expression of TNF-α, TLR4, MyD88, NF-κB in the DQ, DQ+L-GC, DQ+M-GC, and DQ+H-GC groups at each time node increased in the renal tissue. The content of TNF-α, TLR4, MyD88, NF-κB in kidney tissue of the DQ+L-GC, DQ+M-GC, and DQ+H-GC groups at each time node was lower than that in the DQ group.

CONCLUSION

(1) Diquat can cause kidney damage in rats, mainly manifested as renal tubular atrophy, epithelial cell edema, capillary congestion and dilation, and the renal function damage indicators have been improved to varying degrees. (2) Glucocorticoids have therapeutic effects on acute kidney injury in rats exposed to diquat. During the treatment, the efficacy of glucocorticoids did not increase with increasing doses after reaching a dose of 4.2 mg/kg. (3) TLR4 receptor-mediated TLR4/Myd88/NF-κB signaling pathway is involved in the inflammatory response of acute kidney injury in diquat poisoning rats. Glucocorticoids can inhibit the inflammatory response, thereby affecting the expression of TLR4/Myd88/NF-κB signaling pathway-related proteins.

Salidroside Protects Acute Kidney Injury in Septic Rats by Inhibiting Inflammation and Apoptosis

Purpose

To clarify the protective effect and mechanism of salidroside (SLDS) on acute kidney injury (AKI) in septic rats.

Methods

We pretreated rats with different doses of SLDS and analyzed the impact of SLDS on the survival of septic rats. We evaluated the levels of inflammatory factors in rats, the expression of NF-ƙB p65 in the kidney, and the apoptosis of kidney tubular epithelial cells (KTECs).

Results

SLDS significantly decreased the mortality of septic rats, and it reduced the levels of TNF-α, IL-1β, and IL-17A in plasma and kidneys and decreased the levels of serum creatinine, plasma renal injury molecule-1 and plasma neutrophil gelatin-associated lipocalin. Moreover, SLDS could significantly decrease the expression of NF-ƙB p65 in kidney tissues and the apoptotic number of KETCs, while reducing the mRNA levels of Caspase-3 and Bax mRNA, and increasing the level of Bcl-2 mRNA.

Conclusion

SLDS pretreatment protects against AKI in septic rats by inhibiting the inflammation of kidney and the apoptosis of KTECs.

Diagnostic value of miR-155 for acute lung injury/acute respiratory distress syndrome in patients with sepsis

Objective

We aimed to investigate the diagnostic value of microRNA-155 (miR-155) for acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) in patients with sepsis.

Methods

In this prospective study, we used Spearman correlation analysis to investigate relationships between miR-155 expression and inflammatory factors, oxygenation ratio (PaO₂/FiO₂), and ALI/ARDS score, and used area under the receiver operating characteristic curve (AU-ROC) to evaluate miR-155's diagnostic accuracy for ALI/ARDS in patients with sepsis.

Results

In total, 156 patients with sepsis were enrolled in our study, of which 41 had ALI and 32 had ARDS. miR-155 expression in plasma of patients with sepsis and ALI/ARDS was significantly higher than that of patients with sepsis but no ALI/ARDS. The miR-155 level in patients with sepsis and ALI/ARDS was positively correlated with interleukin (IL)-1β and tumor necrosis factor (TNF)-α levels and ALI/ARDS score, but negatively correlated with PaO₂/FiO₂. The AU-ROC of plasma miR-155 for diagnosis of sepsis with ALI/ARDS was 0.87, and plasma miR-155, IL-1β, and TNF-α had high sensitivity and specificity for the diagnosis of sepsis with ALI/ARDS.

Conclusion

miR-155 is highly expressed in plasma of patients with septic ALI/ARDS; it is positively correlated with lung function and can be used for early diagnosis.

Pretreatment with S-Nitrosoglutathione Attenuates Septic Acute Kidney Injury in Rats by Inhibiting Inflammation, Oxidation, and Apoptosis

Objective

We aimed to investigate the protective effect of s-nitrosoglutathione (SNG) pretreatment on acute kidney injury (AKI) in septic rats.

Methods

We constructed a rat model of sepsis by cecal ligation and puncture and observed the survival of the rats. We obtained kidney and blood samples from rats, observed the pathological damage to the kidney tissues, and evaluated kidney function and the expression levels of inflammatory factors. We also detected the expression of induced nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in the kidneys by immunohistochemistry and evaluated the apoptosis of kidney tubular epithelial cells (KTEC) by TUNEL.

Results

Pretreatment with SNG significantly reduced the mortality of septic rats, attenuated kidney pathological damage, and decreased the levels of serum creatinine, plasma neutrophil gelatinase-associated lipocalin, and plasma kidney injury molecule-1. Moreover, SNG pretreatment decreased the levels of TNF-α and IL-1β in serum and kidney and reduced the expressions of NO, iNOS, PGE2, and COX-2 in the kidneys. Furthermore, pretreatment with SNG significantly reduced the apoptotic rate of KTEC and decreased the levels of caspase-3 and Bax mRNA, but increased the level of Bcl-2 mRNA.

Conclusion

Pretreatment with SNG has a protective effect on AKI in septic rats, and the specific mechanisms are related to inhibition of inflammation, oxidation, and apoptosis.

Protective Effect of N-Acetylcysteine Pretreatment on Acute Kidney Injury in Septic Rats

BACKGROUND

The aim of this study is to investigate the protective effect of N-acetylcysteine (NAC) pretreatment on acute kidney injury in septic rats.

METHODS

We constructed a septic rat model by cecal ligation and perforation (CLP) and assessed kidney tissue pathologic damage, renal function changes, and inflammatory factor levels. Meanwhile, we also assessed oxide and antioxidant enzyme levels in kidney tissues, observed apoptosis of kidney tissues, and evaluated mitochondrial membrane activity in renal cortical cells.

RESULTS

Pretreatment of NAC significantly alleviated pathologic damage of kidney tissues in septic rats; decreased the levels of serum creatinine, blood urea nitrogen, plasma neutrophil gelatinase-associated lipocalin, and kidney injury molecule-1; and reduced the expression of tumor necrosis factor a, interleukin [IL]-1β, IL-6, and IL-8. Furthermore, NAC pretreatment reduced the level of protein-nitrotyrosine adducts and malondialdehyde in CLP-induced kidney tissues, while elevated the levels of superoxide dismutase, glutathione peroxidase, and catalase. Moreover, pretreatment of NAC reduced the number of apoptosis in kidney tissues induced by CLP, decreased the mRNA levels of caspase-3, caspase-9, cytochrome c, and poly ADP-ribose polymerase, and increased mitochondrial membrane activity in renal cortical cells (complex I/II/III/IV).

CONCLUSIONS

NAC pretreatment has protective effects on acute kidney injury induced by CLP, and its mechanism is closely related to anti-inflammatory, antioxidation, antiapoptosis, and regulation of mitochondrial function.

The therapeutic effect of dexmedetomidine on protection from renal failure via inhibiting KDM5A in lipopolysaccharide-induced sepsis of mice

BACKGROUND

Sepsis is an inflammatory response undergoing the complicate pathophysiological changes for host defense against pathogens. Previous studies suggested that dexmedetomidine (DEX) was served to controlling the over-reactive inflammatory effects to protect from the sepsis-induced organ failure via modulating histone methylation. However, the genome-wide changes of histone methylations upon DEX for sepsis treatment were poorly explored.

MATERIALS AND METHODS

The acute kidney injury (AKI) mouse model were induced by lipopolysaccharide (LPS). DEX and KDM5 (H3K4 demethylases) inhibitors were used to add additionally. H3K4me3 antibody was used to conduct the ChIP-seq assay in renal cortex tissues.

RESULTS

We observed that the overall H3K4me3 levels were obviously declined in AKI group compared to the normal control. We further observed that the therapeutic effect of DEX was basically equal with CPI-455 and KDM5A-IN-1 but better than PBIT. The overall H3K4me3 level was reduced in AKI group compared to DEX (p = 0.008), and KDM5A-IN-1 groups (p = 0.022). The H3K4me3 enrichment of the multiple genes associated with inflammatory cytokines such as TNF-α, NOS2 and CCL2 increased in AKI model, but decreased upon DEX or KDM5A-IN-1 treatment. Consistently, transcription and protein levels of genes such as TLR4, MYD88, MTA1, PTGS2, CASP3 associated with NF-κB signaling pathway were all compromising after treated with DEX or KDM5A-IN-1 groups compared to AKI group.

CONCLUSION

Taken together, our data determined that DEX could attenuate AKI through KDM5A inhibition in sepsis.