Acute Kidney Injury In Rats Research Articles

Head-to-head comparison of two SGLT-2 inhibitors on AKI outcomes in a rat ischemia-reperfusion model

The CREDENCE trial testing canagliflozin and the EMPA-REG OUTCOME trial testing empagliflozin suggest different effects on acute kidney injury (AKI). AKI diagnosis was mainly made based on changes of serum creatinine (sCr) although this also reflect mode of action of SGLT-2 inhibitors. We analyzed both compounds in a rat AKI model. The renal ischemia-reperfusion injury (I/R) model was used. Four groups were analyzed: sham, I/R+placebo, I/R+canagliflozin (30 mg/kg/day), I/R+ empagliflozin (10 mg/kg/day). Glucose excretion was comparable in both treatment groups indicating comparable SGLT-2 inhibition. Comparing GFR surrogate markers after I/R (sCr and blood urea nitrogen (BUN)), sCr peaked 24 h after I/R, BUN after 48 h, respectively, in the placebo treated I/R group. At all investigated time points after I/R sCr and BUN was higher in the I/R + canagliflozin group as compared to placebo treated rats, whereas the empagliflozin group did not differ from the placebo group. I/R led to tubular dilatation and necrosis. Empagliflozin was able to reduce that finding whereas canagliflozin had no effect. Treatment with empagliflozin also resulted in a significant reduction in an improved inflammatory score (p = 0.006). Renal expression of kidney injury molecule-1 (KIM-1) increased after I/R and empagliflozin but not canagliflozin significantly alleviated KIM-1 expression. I/R reduced urinary miR-26a excretion. Empagliflozin but not canagliflozin was able to restore normal levels of urinary miR-26a. This study in an AKI model confirmed safety data in the EMPA-REG OUTCOME trial suggesting that empagliflozin might reduce AKI risk. The empagliflozin effects on KIM-1 and miR-26a might indicate beneficial regulation of inflammation. These data should stimulate clinical studies with AKI risk as primary endpoint.

Inhibition of Homeobox D10 Alleviates Acute Kidney Injury by Upregulating PI3K/AKT Signaling Proteins

Purpose. To observe the protective effect of homeobox D10 (HOXD10) on acute kidney injury (AKI) by regulating PI3K/AKT signaling pathway is the purpose of this study.Methods. 30 rats were randomly divided into three groups: blank control group, model group, and HOXD10 interference group. The kidney function indexes, HOXD10 protein expression, histopathological features, tubulointerstitial injury, and PI3K and AKT protein expression levels of the three groups were analyzed. Results. Compared with the blank control group, the kidney weight, BUN and SCr in model group increased significantly, and TIL score was higher ( P > 0.05 ). The expression of HOXD10 in model group and HOXD10 interference group were higher than blank control group, and the expression of HOXD10 in HOXD10 interference group was lower than model group ( P < 0.05 ). After we administered HOXD10 blocker to AKI rats, pathological sections by HE staining showed that the kidney tissue damage was significantly reduced compared with the model group, and the expression levels of BUN and SCr in kidney tissue decreased, and the TIL score decreased. The expression of p-PI3K and p-AKT decreased after kidney injury. Compared with the model group, the phosphorylation levels of PI3K and AKT in HOXD10 interference group were significantly increased ( P < 0.05 ). Conclusion. Downregulation of HOXD10 can play a protective role on AKI by activating PI3K/AKT signaling pathway, which can reduce tubulointerstitial injury and improve kidney function.

Panax notoginseng Alleviates Sepsis-Induced Acute Kidney Injury by Reducing Inflammation in Rats.

Background Sepsis is defined as a host inflammatory response to infection that can result in end-organ dysfunction. One of the most common consequences of sepsis is acute kidney injury (AKI). Panax notoginseng powder (PNP) has been previously reported to protect against overactive inflammation process. However, the potential effect of PNP on septic AKI is poorly described. The current study was conducted to investigate the protective effects of PNP in septic AKI rats. Methods A model of septic AKI was established on male SD rats by using the cecal ligation and puncture procedure. PNP was administrated by gavage after the cecal ligation and puncture (CLP) procedure, and the mice were sacrificed at 6, 12, and 72 h after induction of sepsis. The serum and kidney samples were collected and assayed for biochemical tests, histopathological staining, inflammation, and apoptosis-related gene/protein expression. In addition, 15 rats in each group were used to calculate the 7-day survival rate. Results CLP-induced kidney injury was observed by the histopathological score, which markedly was attenuated by PNP treatment. Consistently, PNP intervention significantly alleviated the elevated levels of serum creatinine and blood urea nitrogen in CLP-induced sepsis rats. The CLP procedure also triggered proinflammatory cytokine production and increased the expression of various inflammation-related proteins in the kidneys. However, PNP inhibited the renal expression of IL-18, IL-1β, TNF-α, and IL-6 to substantially improve inflammatory response. Mechanistically, CLP induced the increase of the NF-κB p65 level in the injured kidneys, while PNP notably inhibited the corresponding protein expression. Conclusion PNP attenuated kidney inflammation to protect against CLP-induced septic AKI in rats via inhibiting the NF-κB signaling pathway.

Circ_UBE2D2 Attenuates the Progression of Septic Acute Kidney Injury in Rats by Targeting miR-370-3p/NR4A3 Axis.

As circ_UBE2D2 has been confirmed to have targeted binding sites with multiple miRNAs involved in septic acute kidney injury (SAKI), efforts in this study are directed to unveiling the specific role and relevant mechanism of circ_UBE2D2 in SAKI. HK-2 cells were treated with lipopolysaccharide (LPS) to construct SAKI model in vitro. After sh-circ_UBE2D2 was transfected into cells, the transfection efficiency was detected by qRT-PCR, cell viability and apoptosis were determined by MTT assay and flow cytometry, and expressions of Bcl-2, Bax and Cleaved-caspase 3 were quantified by western blot. Target genes associated with circ_UBE2D2 were predicted using bioinformatics analysis. After the establishment of SAKI rat model, HE staining and TUNEL staining were exploited to observe the effect of circ_UBE2D2 on tissue damage and cell apoptosis. The expression of circ_UBE2D2 was overtly elevated in LPS-induced HK-2 cells. Sh-circ_UBE2D2 can offset the inhibition of cell viability and the promotion of cell apoptosis induced by LPS. Circ_UBE2D2 and miR-370-3p as well as miR-370-3p and NR4A3 have targeted binding sites. MiR-370-3p inhibitor reversed the promoting effect of circ_UB2D2 silencing on viability of LPS-treated cells, but shNR4A3 neutralized the above inhibitory effect of miR-370-3p inhibitor. MiR-370-3p inhibitor weakened the down-regulation of NR4A3, Bax and Cleaved caspase-3 and the up-regulation of Bcl-2 induced by circ_UB2D2 silencing, but these trends were reversed by shNR4A3. In addition, sh-circ_UBE2D2 could alleviate the damage of rat kidney tissue. Circ_UBE2D2 mitigates the progression of SAKI in rats by targeting miR-370-3p/NR4A3 axis.

Ramipril mitigates Glycerol‐induced Acute Kidney Injury in Rats via its Anti‐oxidant, Anti‐renin and Anti‐apoptosis Effects

A sudden decrease in the functionality of the kidney with concomitant structural damage and functional loss is known as acute kidney injury (AKI), with some of the potential causes having to do with a focal mismatch between oxygen and nutrient delivery to the nephrons. Increased energy demands on account of cellular stress is another cause [Kellum et al 2021]. AKI occurs when renal function is acutely decreased, so waste products accumulate within the body, making the body unable to maintain electrolyte, acid‐base, and water balance [Bhatraju et al 2020]. As a result of the decrease in the kidney’s ability to carry out its perfusion activity, the epithelial cells lost the ability to maintain sufficient intracellular ATP for essential processes. This ATP depletion leads to cell injury. Depending on the severity of ATP depletion, cell death by necrosis or apoptosis could occur [Biswas et al 2018]. Studies have actually demonstrated that the pathogenesis of glycerol‐induced AKI involves myoglobin toxicity, reactive oxygen species, inflammation, and redox‐active iron [Al Asmari et al 2017; Wu et al 2017]. Currently, animal models of glycerol‐induced AKI are widely used [Mousleh et al 2018]. Glycerol injection into the muscle causes the release of myoglobin and other muscle contents into the circulation, ultimately resulting in AKI.Twenty animals divided into four groups of five animals per group were used. Group I served as control while group II received glycerol on day 8 only. Groups III and IV were administered with pioglitazone and ramipril for 7 days respectively and on day 8 received glycerol. On day 9 blood samples were collected for serum biochemical analysis of markers of oxidative stress, enzymatic and non‐enzymatic antioxidants, creatinine and blood urea nitrogen. Animals were sacrificed thereafter; and kidney tissues were harvested for histopathology and immunohistochemistry. Expression of caspase 3, renin receptor, NF‐κB, and KIM‐1 were carried out.Results from this study showed that ramipril and pioglitazone significantly inhibited markers of oxidative stress while also significantly increased the levels of enzymatic and non‐enzymatic anti‐oxidant markers. These drugs caused decreased levels of creatinine and BUN. While massive leucocytes infiltration and congestion of the kidney occurred in the toxicant group, it was mild in the ramipril treated group and the two drugs significantly inhibited the expressions of the four proteins, which were highly expressed in the toxicant group.Thus ramipril and pioglitazone have nephroprotective effect and mitigated acute kidney injury through their anti‐inflammatory, anti‐apoptosis, anti‐renin and anti‐oxidant properties.Some ReferencesAl Asmari AK, Al Sadoon KT, Obaid AA, Yesunayagam D, Tariq M. Protective effect of quinacrine against glycerol‐induced acute kidney injury in rats. BMC Nephrol. 2017; 18:41.Kellum JA, Romagnani P, Ashuntantang G, Ronco C, Zarbock A, Hans‐ Joachim A. Acute kidney injury. Disease Primers 2021; 7: 52

Moringa oleifera extract protects against rhabdomyolysis‐induced acute kidney injury

Acute kidney injury (AKI) is a life‐threatening abrupt disruption in kidney function. The pathophysiological mechanisms of AKI are poorly understood. Also, there are currently no effective drugs to treat AKI. Phytochemicals from Moringa oleifera plants exhibit antihypertensive, cholesterol‐lowering, diuretic, and hepatoprotective properties. This study aims to determine if Moringa oleifera extract can ameliorate rhabdomyolysis‐induced AKI and its possible mechanisms of action.Experimental rats were randomly divided into five groups. Rhabdomyolysis was induced by intramuscular glycerol injection. Group A received distilled water only. Group B received distilled water, followed by 50% glycerol on the 8th day. Group C and D received 50 and 100 mg/kg methanol stem extract of Moringa oleifera (orally) for seven days and glycerol on the 8th day. Group E received 100 mg/kg of methanol stem extract of Moringa oleifera alone for seven days and normal saline on the 8th day. Necropsy was performed 24 h after glycerol treatment. Blood and kidneys samples were collected for biochemical, histopathological, and immunohistochemical analyses.Significant decreases in superoxide dismutase, glutathione peroxidase, glutathione S‐transferase, glutathione, protein thiols, and non‐protein thiols were observed in animals treated with only glycerol when compared with the control groups. Glycerol treatment also caused a significant increase in markers of AKI and inflammation, including creatinine, nitric oxide, urea, hydrogen peroxide, malondialdehyde, protein carbonyl, and advanced oxidative protein products. Immunohistochemical staining of renal NF‐ƙβ and KIM‐1 was also elevated in glycerol‐treated rats. Treatment with methanol stem bark extract of Moringa oleifera ameliorated glycerol‐induced oxidative stress, kidney damage, and inflammation.The methanol stem extract of Moringa oleifera alleviated rhabdomyolysis‐induced AKI in rats through its antioxidant and anti‐inflammatory properties.

The Role of the Superior Cervical Sympathetic Ganglion in Ischemia Reperfusion-Induced Acute Kidney Injury in Rats.

Acute kidney injury (AKI) has been found to be a serious clinical problem with high morbidity and mortality, and is associated with acute inflammatory response and sympathetic activation that subsequently play an important role in the development of AKI. It is well known that the sympathetic nervous system (SNS) and immune system intensely interact and mutually control each other in order to maintain homeostasis in response to stress or injury. Evidence has shown that the superior cervical sympathetic ganglion (SCG) participates in the bidirectional network between the immune and the SNS, and that the superior cervical ganglionectomy has protective effect on myocardial infarction, however, the role of the SCG in the setting of renal ischemic reperfusion injury has not been studied. Here, we sought to determine whether or not the SCG modulates renal ischemic reperfusion (IR) injury in rats. Our results showed that bilateral superior cervical ganglionectomy (SCGx) 14 days before IR injury markedly reduced the norepinephrine (NE) in plasma, and down-regulated the increased expression of tyrosine hydroxylase (TH) in the kidney and hypothalamus. Sympathetic denervation by SCGx in the AKI group increased the level of blood urea nitrogen (BUN) and kidney injury molecule-1 (KIM-1), and exacerbated renal pathological damage. Sympathetic denervation by SCGx in the AKI group enhanced the expression of pro-inflammatory cytokines in plasma, kidney and hypothalamus, and increased levels of Bax in denervated rats with IR injury. In addition, the levels of purinergic receptors, P2X3R and P2X7R, in the spinal cord were up-regulated in the denervated rats of the IR group. In conclusion, these results demonstrate that the sympathetic denervation by SCGx aggravated IR-induced AKI in rats via enhancing the inflammatory response, thus, the activated purinergic signaling in the spinal cord might be the potential mechanism in the aggravated renal injury.

Shikonin attenuates kidney tubular epithelial cells apoptosis, oxidative stress, and inflammatory response through nicotinamide adenine dinucleotide phosphate oxidase 4/PTEN pathway in acute kidney injury of sepsis model.

Natural compounds were used in the treatment of acute kidney injury (AKI) caused by sepsis. This study investigated the function of shikonin from the roots of Arnebia purpurea in sepsis-induced AKI model. The target genes of shikonin were predicted by traditional Chinese medicine integrative database (TCMID). The markers of kidney injury, oxidative stress, and inflammatory factors were measured by enzyme-linked immunosorbent assay (ELISA). The pathological changes of kidney tubules were assessed by Hematoxylin and Eosin staining. Apoptosis of kidney tubular epithelial cells (KTECs) was detected by the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling. Protein expression was measured by western blot. Shikonin significantly improved kidney injury induced by cecal ligation and perforation (CLP). Besides, shikonin reduced KTECs apoptosis, malondialdehyde (MDA), reactive oxygen species (ROS), interleukin-1β (IL-1β), IL-6, and tumor necrosis factor-α (TNF-α) levels, while augmented SOD and IL-10 levels. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase4 (NOX4) was predicted a target gene of shikonin. The expression of NOX4 was significantly inhibited in shikonin-treated group and the levels of phosphatidylinositol 3,4,5-trisphosphate 3-phosphate and dual specificity protein phosphate (PTEN) and p-p65 were decreased, while level of p-Akt was elevated. In vitro experiments, shikonin inhibited cell apoptosis, inflammatory, and ROS in human HK-2 cells and rat TECs. Shikonin downregulated expression of NOX4, PTEN and p-p65, and upregulated p-AKT and Bcl-2 expression in HK2 cells treated with lipopolysaccharide (LPS). Moreover, overexpression of NOX4 enhanced the effect of LPS on the expression level of PTEN, p-p65, p-AKT, and Bcl-2, which was reversed by the addition of shikonin. Taken together, shikonin could improve sepsis-induced AKI in rats, and attenuate the LPS induced KTECs apoptosis, oxidative stress, and inflammatory reaction via modulating NOX4/PTEN/AKT pathway.

Inhibition of Circ-Snrk ameliorates apoptosis and inflammation in acute kidney injury by regulating the MAPK pathway

Background Circular RNA (circRNA) is involved in the process of acute kidney injury (AKI), but only a few circRNAs have been reported. In the study, we investigated a new circRNA and its association with AKI. Methods An AKI model was established in Sprague-Dawley rats, followed by serum creatinine and urea nitrogen tests measured by a biochemical analyzer. The pathological changes and apoptosis in the renal tissue were detected by Hematoxylin and Eosin, and TUNEL staining. Then, circRNA expression in AKI was determined by quantitative real-time-PCR (qRT-PCR). NRK-52E cells were induced with hypoxia/reoxygenation (H/R) as in vitro models and the circ-Snrk level was tested by qRT-PCR. The effects of circ-Snrk in H/R-induced NRK-52E cells were assessed by flow cytometry, western blot, and enzyme-linked immunosorbent assay. Finally, RNA sequencing and western blot analysis were used to validate the mRNA profile and pathways involved in circ-Snrk knockdown in H/R-induced NRK-52E. Results A reliable AKI rat model and H/R cell model were established. qRT-PCR demonstrated that circ-Snrk level was upregulated in AKI left kidney tissue and NRK-52E cells with H/R treatment. Circ-Snrk knockdown inhibited apoptosis of NRK-52E cells and secretion of inflammatory factors (IL-6 and TNF-α). RNA sequencing showed that the mRNA profile changed after inhibition of circ-Snrk and differential expression of mRNA mainly enriched various signaling pathways, including MAPK signaling pathway. Furthermore, western blot indicated that circ-Snrk knockdown could inhibit the activation of p-JNK and p-38 transcription factors. Conclusions Circ-Snrk is involved in AKI development and associated with the MAPK signaling pathway in AKI.

Protective effect of tin chloride on rhabdomyolysis-induced acute kidney injury in rats.

The heme component of myoglobin plays a crucial role in the pathogenesis of rhabdomyolysis-associated acute kidney injury (RM-AKI). Heme oxiganenase-1 (HO-1) is the rate-limiting enzyme of heme catabolism, and its metabolites, iron, biliverdin, and carbon monoxide, have antioxidant properties. Tin chloride (SnCl2) is a kidney specific HO-1 inducer. In this study, we examined whether the induction of HO-1 in the kidney by SnCl₂ pretreatment ameliorates RM-AKI in rats and if the effect is due to the degradation of excess renal free heme. We developed an RM-AKI rat (male Sprague-Dawley rats) model by injecting glycerol (Gly) in the hind limbs. RM-AKI rats were pretreated with saline or SnCl₂ or additional SnMP (tin mesoporphyrin, a specific HO inhibitor) followed by Gly treatment. Serum blood urea nitrogen (BUN) and creatinine (Crea) were measured as indicators of renal function. Renal free heme level was assessed based on the levels of δ-aminolevulinate synthase (ALAS1), a heme biosynthetic enzyme, and nuclear BTB and CNC homology 1 (Bach1), an inhibitory transcription factor of HO-1. Elevated free heme levels lead to decreases in ALAS1 and nuclear Bach1. After 24 h of Gly injection, serum BUN and Crea levels in saline-pretreated rats were significantly higher than those in untreated control rats. In contrast, SnCl₂-pretreated rats showed no significant increase in the indices. However, additional treatment of SnMP abolished the beneficial effect of SnCl₂. Renal ALAS1 mRNA levels and renal nuclear Bach1 protein levels in the saline pretreated rats were significantly lower than those in control rats 3 h after Gly injection. In contrast, the levels in SnCl₂-pretreated rats were not altered. The findings indicate that SnCl2 pretreatment confers protection against RM-AKI by virtue of HO-1 induction in the renal system, at least in part through excess free heme degradation.

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

PurposeTo clarify the protective effect and mechanism of salidroside (SLDS) on acute kidney injury (AKI) in septic rats.MethodsWe 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).ResultsSLDS 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.ConclusionSLDS pretreatment protects against AKI in septic rats by inhibiting the inflammation of kidney and the apoptosis of KTECs.

Effect of Dietary Supplementation of Lemon Balm (Melissa officinalis L.) on Acute Kidney Injury in Rats

Effect of Dietary Supplementation of Lemon Balm (Melissa officinalis L.) on Acute Kidney Injury in Rats

Piperazine ferulate attenuates gentamicin-induced acute kidney injury via the NF-κB/NLRP3 pathway

BackgroundPiperazine ferulate (PF) is widely used in chronic nephritis and nephrotic syndrome in clinic. PF can improve diseases related inflammation by inhibiting the activation of nuclear factor kappa-B (NF-κB) signal. Acute kidney injury (AKI) is usually associated with the occurrence and development of renal inflammation. However, the nephroprotective effect and anti-inflammatory mechanisms of PF on AKI are not clear. PurposeThis study aimed to investigate the nephroprotective effects of PF on gentamicin (GM) induced AKI in rats and its potential mechanisms. MethodsMale Sprague Dawley (SD) rats were intraperitoneally injected with GM (100 mg/kg/day) with or without PF (50 and 100 mg/kg/day) for 7 consecutive days. In vitro, the NRK-52e cells were exposed to GM (7 mg/ml) with or without PF (62.5 μg/ml) treatment. The renal injury and cell damage were assessed subsequently. ResultsOur findings showed that PF treatment can significantly improve renal function, reduce renal pathological changes, and attenuate inflammatory response in rats treated with gentamicin. Besides, PF could significantly reduce the cell damage and cellular inflammatory response. In terms of mechanisms, our study revealed that PF can evidently inhibit the activation of NF-κB and nod-like receptor family pyrin domain protein 3 (NLRP3) inflammasome. Meanwhile, it could down regulate the expressions of protein and gene of p-IKKα, p-IKKβ, p-p65, p65, p50, p105, NLRP3 and IL-1β. ConclusionOur findings showed that PF may improve inflammation by inhibiting the NF-κB/NLRP3 pathway, so as to attenuate AKI.

Dexmedetomidine inhibits oxidative stress in sepsis-induced acute kidney injury in rats by regulating GSK-3β/Nrf2/ARE axis

Purpose: To determine the effect of dexmedetomidine on sepsis-mediated acute kidney injury (SAKI) in rats.
 Methods: Twenty-four SD rats were randomly divided into blank untreated control group, model group given lipopolysaccharide at a dose of 10 mg/kg, dexmedetomidine (Dex) group, and glycogen synthase kinase-3 beta (GSK-3β) inhibitor group given sb216763. In addition, Dex and inhibitor groups received the same dose of lipopolysaccharide as model group. There were 10 rats in each group. Pathological changes in kidney tissue, and the levels of related oxidative stress indices were determined.
 Results: Compared with the model group, granular degeneration of renal tubular epithelial cells was significantly reduced in Dex group, and the population of exfoliated cells decreased (p < 0.05). The levels of malondialdehyde (MDA) and reactive oxygen species (ROS) in dexmedetomidine and GSK-3β inhibitor groups were significantly reduced, while superoxide dismutase (SOD), glutathione (GSH) and catalase (CAT) activities were markedly raised, relative to model group (p < 0.05). Protein levels of p- GSK-3β and Nrf2 markedly were raised in dexmedetomidine and GSK-3β inhibitor groups (p < 0.01). After intervention with Dex and GSK-3β inhibitor, there were marked upregulations in mRNA and protein expression levels of heme oxygenase-1 (HO-1), when compared with model group (p < 0.05).
 Conclusion: Dexmedetomidine ameliorates SAKI injury in rats via suppression of oxidative stress. Its mechanism of action may be related to the regulation of GSK-3β/Nrf2/ARE signaling pathway. This finding may be a novel approach to the clinical management of SAKI.

Nigella sativa and its main constituent, thymoquinone protect against glycerol-induced acute kidney injury in rats.

Rhabdomyolysis is a life-threatening disease caused by releasing myoglobin from injured myocytes, which results in acute kidney injury. In this study, the effect of aqueous-alcoholic extract of Nigella sativa (NS) and thymoquinone (TQ) on rhabdomyolysis-induced kidney damage in rats was investigated. There were five groups of rats (n=8): Control, rhabdomyolysis, rhabdomyolysis treated with NS aqueous-alcoholic extract (200 and 400 mg/kg) and TQ (15 mg/kg). Treatments were given for 7 days (two days before and four days after glycerol injection). Glycerol was injected intramuscularly on the third day of the experiment for induction of rhabdomyolysis. Renal function parameters on the first, fourth, and seventh days of the experiment and renal oxidative stress and histological changes at the end of this study were assessed. Glycerol injection caused a significant increase in serum level of urea, creatinine, creatine phosphokinase, urine output and tissue MDA compared to the control animals (p<0.05-0.001). Administration of NS extract and TQ significantly decreased serum urea and creatinine on days 4 and 7, creatine phosphokinase on day 4, and urine output on day 7 compared to the rhabdomyolysis group (p<0.05-0.001). Compared to the rhabdomyolysis group, treatment with NS extract and TQ improved kidney histological abnormalities (p<0.01-0.001). The catalase enzyme activity in the group treated with NS 400 mg/kg and thiol content in the NS 400 mg/kg and TQ groups were significantly higher than those of the rhabdomyolysis group (p<0.05-0.01). NS extract and to some extent TQ protect the kidney from rhabdomyolysis-induced injury.

Identifying of miRNA-mRNA Regulatory Networks Associated with Acute Kidney Injury by Weighted Gene Co-Expression Network Analysis.

BackgroundAcute kidney injury (AKI) is a clinical emergency characterized by a dramatic decline in renal function and the accumulation of metabolic waste products in the body, with a high morbidity and mortality rate. The pathogenesis of AKI remains unclear and there are no effective treatment options.MethodsWe aimed to identify critical genes involved in the pathogenesis of AKI and construct a miRNA–mRNA regulatory network using gene expression data downloaded from Gene Expression Omnibus (GSE85957) for 38 kidneys of AKI and 19 control rats and cisplatin treated kidneys of 3 AKI and 3 control rats. Data in GSE85957 were processed using weighted gene co-expression network analysis (WGCNA), and biological function analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were used to analyze the functions associated with critical genes.ResultsTwenty-eight modules in the GSE85957 dataset were identified by WGCNA, of which 103 genes in the orange module and 30 genes in the black module were closely associated with AKI and dose. Biological function analysis of genes in the orange and black modules revealed that skeletal muscle cell differentiation, tissue development and organ development were involved in the pathological changes of AKI. Combining with our experimentally processed AKI rat kidney data, eight genes (Atf3, Egr1, Egr2, Fos, Fosb, Gdf15, Serpine1 and Nr1d1) were identified as potential biomarkers of AKI, and miRNA–mRNA regulatory networks were constructed based on the above eight critical genes. Further tissue validation revealed that Egr1 and Fos were highly expressed in AKI.ConclusionOur study identified potential biomarkers of AKI and constructed an associated miRNA–mRNA regulatory network, which may provide new insights into the molecular pathogenesis of AKI.

Leonurine Preconditioning Attenuates Ischemic Acute Kidney Injury in Rats by Promoting Nrf2 Nuclear Translocation and Suppressing TLR4/NF-κB Pathway.

Despite the precise mechanisms for renal ischemia/reperfusion (I/R)-induced acute kidney injury (AKI) are poorly understood, nuclear factor erythroid 2 related factor 2 (Nrf2) and Toll-like receptor 4 (TLR4) pathways were considered as the important targets. Leonurine (LEO) is a special alkaloid extracted from Chinese motherwort (Leonurus japonicus Houtt), which has an anti-inflammatory effect and reduces oxidative stress. We conducted the study to explore the efficacy of LEO against I/R-induced AKI in rats and further investigated the underlying mechanisms. Ischemic renal injury was induced by temporary vascular clamping for 45 min. We have measured the levels of inflammation-related biomarkers and antioxidative stress markers. Next, Western blot analysis and Real-time PCR were performed to analyze whether the Nrf2 and TLR4/nuclear factor-kappaB (NF-κB) pathways were involved in this process. We found that LEO pretreatment remarkably decreased serum creatinine and blood urea nitrogen (BUN) in I/R rats and attenuated acute tubular damage. In addition, LEO markedly increased the expression of antioxidant proteins and decreased the levels of inflammatory factors. Further study revealed that LEO promoted Nrf2 into the nucleus, promoted the expression of heme oxygenase-1 (HO-1) and quinone oxidoreductase 1 (NQO-1), and suppressed the TLR4/NF-κB signal pathway in kidney tissues of ischemic AKI rats. The study reveals that LEO has a protective effect to prevent ischemic AKI through activation of Nrf2 nuclear translocation resisting oxidative stress injury and inhibition of the TLR4/NF-κB pathway mediated inflammatory gene expression.

Physalis Alkekengi L. var. Franchetii Calyx Alleviates Gentamicin-Induced Acute Kidney Injury in Rats: Modulation of Oxidative Stress, Inflammation, and Apoptosis

Physalis Alkekengi L. var. Franchetii Calyx Alleviates Gentamicin-Induced Acute Kidney Injury in Rats: Modulation of Oxidative Stress, Inflammation, and Apoptosis

Choline and citicoline ameliorate oxidative stress in acute kidney injury in rats.

The purpose of this study is to investigate the effects of cholinergic anti-inflammatory pathway (CAP)-activating drugs, choline and citicoline (Cytidinediphosphate-choline, CDP-choline), on lipopolysaccharide (LPS)-induced acute kidney injury (AKI) parameters and the contribution of NADPH Oxidase4 (NOX4) p22phox. Endotoxemia induces a systemic inflammatory response characterized by the production of pro-inflammatory mediators and reactive oxygen species (ROS), which eventually develops acute kidney injury (AKI). NADPH Oxidase4 (NOX4) p22phox pathway contributes to the development of endotoxemia-induced AKI. Inflammatory response can be controlled by CAP. Expressions levels of KIM-1, TNF-α, NOX4, p22phox and NFκB in the kidney tissues of rats were analyzed via RT-PCR in experimental groups; 1. Control, 2. LPS (10 mg/kg) + saline, 3. LPS + CDP-choline (375 mg/kg) and 4. LPS + choline (90 mg/kg). Choline and ROS levels in kidney tissues were also measured by a spectrofluorometric assay. LPS-induced elevations of ROS levels were decreased by CDP-choline or choline administration (p < 0.001). LPS-elevated KIM-1, TNFα, NOX4, p22 phox, and NFκB expressions were significantly decreased by choline or CDP-choline treatments (p < 0.001). Decreased ROS production in kidney tissues in treatment groups suggests that choline or CDP-choline may have therapeutic potential in endotoxemia-associated AKI via downregulating NOX4 and p22phox expressions (Tab. 1, Fig. 5, Ref. 45). Text in PDF www.elis.sk Keywords: endotoxemia, choline, cytidine diphosphate choline, acute kidney injury, reactive oxygen species.

SIRT2 tyrosine nitration by peroxynitrite in response to renal ischaemia/reperfusion injury

Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are the production of renal ischaemia/reperfusion (I/R). The current study is to elucidate a mechanism of SIRT2 tyrosine nitration to accelerate the cell apoptosis induced by peroxynitrite (ONOO‾), the most reactive and deleterious RNS type in renal ischaemia/reperfusion (I/R) injury. Our results demonstrate that there is a significant enhancement of the 3-nitrotyrosine levels in renal tissues of Acute Kidney Injury (AKI) patients and rats that underwent renal I/R, and a positive correlation between the 3-nitrotyrosine level and renal function impairment, indicative of an accumulation of peroxynitrite. Notably, peroxynitrite-evoked nitration of SIRT2 destroyed its enzymatic activity and the capability to deacetylate FOXO3a, and enhanced expression of Bim and caspase3, facilitating renal cell apoptosis in renal ischaemia/reperfusion and SIN-1(peroxynitrite donor) treatment in vitro, and these effects were reversed by FeTMPyP, a peroxynitrite decomposition scavenger. Importantly, we identified that the tyrosine 86 is responsible for SIRT2 nitration and inactivation using site-mutation assay and Mass Spectrography analysis. Altogether, these findings point to a novel protective mechanism that an inhibition of SIRT2 tyrosine nitration can be a promising strategy to prevent ischaemic renal diseases involving AKI.