Acute Kidney Injury In Rats Research Articles

Relationship between cytokeratins CK8/18&19 and KIM-1 level in urine with apoptosis and necrosis of nephrotheliocytes in rats with toxic nephropathy

The aim of the article. The aim of this work was to elucidate the role of apoptosis and necrosis in kidney tissue in the development of acute renal damage in poisoning rats with uranyl acetate. The research objectives included modeling acute poisoning in rats, collecting urine and kidney tissue with identifying markers of programmed cell death, tissue polypeptide antigen (TPA, fragments of cytokeratin CK8/18 19), and KIM-1 level in urine. An analysis of the relationship between an early increase in urinary excretion of the TPA and apoptosis level, a kidney injury molecule KIM-1, and necrosis of the tubular epithelial cells during rat poisoning with nephrotoxin uranyl acetate dihydrate.
 Materials and methods. Uranyl acetate dihydrate (CAS # 6159-44-0) was administered to 18-week old female Sprague-Dawley rats weighing 175199 g by intragastrically at a dose of 30 mg / 100 g body weight once through an atraumatic probe. Rats were divided into 2 groups: group 1 intact animals (12 individuals), group 2 animals with induced AKI (36 individuals). Daily urine was collected before, on the 1st, 3rd, and 7th day after poisoning in metabolic cages. The concentration of creatinine, KIM-1, tissue polypeptide antigen was measured in urine. In the kidney tissue samples, the fraction of dead cells and nephrothelial cells with apoptotic signs of nuclear changes by fluorescence microscopy with AMD Hoechst 33342 staining was determined. Data processing was performed using GraphPad Prism 6.0.
 Results. Acute kidney injury in rats with uranyl acetate dihydrate leads to a rapid increase in urinary excretion of cytokeratin fragments CK8/18 19 due to subtotal damage to nephrothelial cells due to activation of apoptosis, and then an increase in KIM-1 as a marker of necrotic cell death. Fluorescence microscopy of nuclear chromatin stained renal tubule cells showed a significant increase in the proportion of cells with apoptotic bodies, chromatin condensation, and a change in the shape of the nuclei.
 Conclusion. Examination of the curves of risk function showed that only creatinine in blood (p = 0.0002) and urine KIM-1 (p = 0.0005) had a significant level of association with rat mortality and necrosis of the nephrothelial cells. A comparative analysis of the relationship between apoptosis biomarker levels TPA (cytokeratin fragments CK8/18 19) and urinary nephrotoxicity marker KIM-1 with the proportion of kidney cells dying by the mechanism of necrosis and apoptosis revealed positive correlations of Spearman in pairs of cytokeratin CK8/18 19 apoptosis (r = 0.73, 95% CI 0.450.88, p 0.0001), KIM-1 necrosis (r = 0.98, 95% CI 0.960.99, p 0.0001). The revealed relationship indicated the possibility of determining urinary tissue polypeptide antigen TPA as a marker of the early stage of acute kidney damage as a surrogate marker of tubular cell apoptosis, and KIM-1 as a marker for necrosis of nephrothelial cells.

The protective efficacy of vitamin E and cod liver oil against cisplatin-induced acute kidney injury in rats.

Cisplatin (CP) is a highly effective chemotherapeutic agent against neoplasms, but its clinical utility is limited due to the side effects of its dose-dependent nephrotoxicity. Vitamin E (Vit E) and cod liver oil (CLO) are natural substances with chemoprotective effects. The present study was conducted to evaluate the protective effects of Vit E and/or CLO for CP-induced acute kidney injury (AKI) in rats. This study involved 40 mature male Wistar albino rats that were equally allocated into eight groups: Veh, Vit E, CLO, Vit E + CLO, CP, Vit E + CP, CLO + CP, and Vit E + CLO + CP. The co-administration of Vit E and CLO significantly ameliorated CP-induced elevations in serum creatinine (Cr), blood urea nitrogen (BUN), interleukin 1 beta (IL-1β), and interleukin- 6 (IL-6). Further, rats that received Vit E and/or CLO showed significant decrease in malondialdehyde (MDA) and increases in superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH) levels in renal tissues, compared to CP-intoxicated rats. Additionally, the treatment restored the normal histological architecture (except for few cast formations) and upregulated the immunostaining area% of aquaporin 3 (AQP3) and downregulated the immunostaining area% of Bcl2 associated X protein (BAX) and inducible nitric oxide synthase (iNOS). The observed effects were stronger in the combination treatment group. The obtained data revealed that Vit E and CLO co-administration protects against the CP-induced AKI more than monotherapy with Vit E or CLO.

Quercetin Protects Against Acetaminophen-Induced Acute Nephrotoxicity Associated with the Inhibition of Biomarkers of Acute Kidney Injury in Rats

Quercetin Protects Against Acetaminophen-Induced Acute Nephrotoxicity Associated with the Inhibition of Biomarkers of Acute Kidney Injury in Rats

Stevioside protects against rhabdomyolysis-induced acute kidney injury through PPAR-γ agonism in rats.

We explored the potential role of peroxisome proliferator activated receptor-γ (PPAR-γ) in stevioside-mediated renoprotection using rhabdomyolysis-induced acute kidney injury (AKI) model in rats. Rhabdomyolysis refers to intense skeletal muscle damage, which further causes AKI. Glycerol (50% w/v, 8 ml/kg) was injected intramuscularly in rats to induce rhabdomyolysis. After 24 hr, AKI was demonstrated by quantifying serum creatinine, urea, creatinine clearance, microproteinuria, and electrolytes in rats. Further, oxidative stress was measured by assaying thiobarbituric acid reactive substances, generation of superoxide anion, and reduced glutathione levels. Additionally, serum creatine kinase (CK) level was assayed to determine glycerol-induced muscle damage in rats. Pathological changes in rat kidneys were studied using hematoxylin-eosin and periodic acid Schiff staining. Moreover, the expression of apoptotic markers (Bcl-2, Bax) in rat kidneys was demonstrated by immunohistochemistry. Stevioside (10, 25, and 50 mg/kg) was administered to rats, prior to the induction of AKI. In a separate group, bisphenol A diglycidyl ether (BADGE, 30 mg/kg), a PPAR-γ receptor antagonist was given prior to stevioside administration, which was followed by rhabdomyolysis-induced AKI in rats. The significant alteration in biochemical and histological parameters in rats indicated AKI, which was attenuated by stevioside treatment. Pretreatment with BADGE abrogated stevioside-mediated renoprotection, which is suggestive of the involvement of PPAR-γ in its renoprotective effect. In conclusion, stevioside protects against rhabdomyolysis-induced AKI, which may be attributed to modulation of PPAR-γ expression.

Effects of rhEPO on Nrf2 and HO-1 expression in rats with acute kidney injury and its protective effects on kidney

If the kidney suddenly loses its ability to remove waste, acute kidney injury (AKI) will occur that dangerous levels of waste may accumulate, and the chemical composition of the blood may become unbalanced. AKI usually develops rapidly within a few days and is very common in hospitalized patients, especially those in urgent need of intensive care. AKI can be fatal and requires serious treatment. However, it can be reversible. The purpose of this research was to investigate the effects of recombinant human erythropoietin (rhEPO) on the expression of nuclear factor E2-related factor 2 (Nuclear factor E2, Nrf2) and Heme oxygenase (HO-1) in rats AKI and its protective effects on the kidney. For this purpose, 40 SD rats were averagely and randomly divided into 4 groups: control group, sham operation group, model group, and rhEPO group. The rhEPO group was injected with 5% glucose mixed with rhEPO to form 3000 IU/ (kg/d) rhEPO. Except for the rhEPO group, three groups were injected with 5% glucose at the same dose level as the rhEPO group respectively. Before the third administration, the renal pedicle was clamped for 60 min and then perfused for 24 hours. Changes of Serum creatinine (Scr) and Urea nitrogen (BUN) of rats in each group were detected before and after modeling. Twenty-four hours after modeling, renal tissues of rats in each group were taken, and expressions of Nrf2 and HO-1 in renal tissues were detected by qRT-PCR and Western blot methods. There were no significant differences in Scr and BUN contents in the four groups before modeling (p> 0.05). There were no significant differences in Scr and BUN contents in the control group and sham operation group after modeling compared with those before modeling (p> 0.05). Expressions of Nrf2 and HO-1 in the rhEPO group were higher than those in the model group, the sham operation group and the control group (p< 0.05), while expressions of Nrf2 and HO-1 in model group were higher than those in sham operation group and control group (p< 0.05). There were no significant differences in expressions of Nrf2 and HO-1 between the sham operation group and the control group (p> 0.05). rhEPO can induce expressions of Nrf2 and HO-1 in AKI rats. RhEPO has a protective effect on the kidney, which may be related to expressions of Nrf2 and HO-1.

Puerarin alleviates cisplatin-induced acute renal damage and upregulates microRNA-31-related signaling.

Cisplatin (DDP) is a commonly used chemotherapy drug; however, the side effects associated with its use, particularly acute kidney injury (AKI), limit its clinical application. Puerarin is a natural flavonoid extracted from the Chinese medical herb Radix puerariae, which has been reported to alleviate DDP-induced nephrotoxicity. However, the mechanisms underlying puerarin regulation on microRNA (miR)-31-mediated signaling pathways in AKI remain unknown. Thus, the present study aimed to investigate the function of puerarin in a DDP-induced AKI rat model via reverse transcription-quantitative PCR and western blot analyses. The results demonstrated that DDP upregulated the levels of miR-31 in a concentration-dependent manner, both in vitro and in vivo. Furthermore, DDP significantly increased blood urea nitrogen and malondialdehyde content, serum creatinine and histopathological changes, while significantly decreasing the expression levels of superoxide dismutase, catalase and glutathione S-transferase in kidney tissues. TUNEL and western blot analyses indicated that DDP increased the expression levels of apoptotic proteins and affected the Numb/Notch1 signaling pathway, which is downstream of miR-31. The effects induced by DDP were counteracted following treatment with puerarin. Taken together, the results of the present study suggest that puerarin exhibits a renal protective effect against DDP-induced AKI by upregulating miR-31 expression and inhibiting the Numb/Notch1 signaling pathway.

Methanol stem extract of Moringa oleifera mitigates glycerol-induced acute kidney damage in rats through modulation of KIM-1 and NF-kB signaling pathways

Moringa oleifera popularly referred to as wonder plant is a medicinal plant with a remarkable variety of therapeutic purposes. The aim of this study was to assess the ameliorative effect of Moringa oleifera on glycerol-induced acute kidney injury in rats thus renewing interest in the development of new treatment plans. Glycerol (50% v/v in sterile saline, intramuscular) was used to induce acute kidney injury. Group A (control group) received distilled water only, the group B animals (toxicant group) received glycerol alone on the 8th day, and groups C and D animals were given 50 mg/kg and 100 mg/kg of methanol stem extract of Moringa oleifera respectively for seven days and glycerol on the 8th day. Group E animals on the other hand received 100 mg/kg of methanol stem extract of Moringa oleifera alone for seven days and on day 8 received normal saline. To assess renal damage and possible ameliorative effects of the extract, serum blood urea nitrogen (BUN), creatinine, myeloperoxidase, advanced oxidative products, malondialdehyde, superoxide dismutase, reduced glutathione, and protein carbonyl were determined. Histopathological analysis of kidney tissues and immunohistochemical analysis of KIM-1 and NF-ҝB expressions were also carried out on kidney tissues. The results showed that methanol stem bark extract of Moringa oleifera improves glycerol-induced acute kidney injury by inhibiting markers of inflammation, oxidative stress and renal damage by modulating KIM-1 and NF-ҝB signaling pathways. In conclusion, the methanol stem extract of Moringa oleifera blunts glycerol-induced acute kidney injury in rats through its anti-oxidant and anti-inflammatory properties.

Reproducible Large-Scale Isolation of Exosomes from Adipose Tissue-Derived Mesenchymal Stem/Stromal Cells and Their Application in Acute Kidney Injury.

Acute kidney injury (AKI) is a fatal medical episode caused by sudden kidney damage or failure, leading to the death of patients within a few hours or days. Previous studies demonstrated that exosomes derived from various mesenchymal stem/stromal cells (MSC-exosomes) have positive effects on renal injuries in multiple experimental animal models of kidney diseases including AKI. However, the mass production of exosomes is a challenge not only in preclinical studies with large animals but also for successful clinical applications. In this respect, tangential flow filtration (TFF) is suitable for good manufacturing practice (GMP)-compliant large-scale production of high-quality exosomes. Until now, no studies have been reported on the use of TFF, but rather ultracentrifugation has been almost exclusively used, to isolate exosomes for AKI therapeutic application in preclinical studies. Here, we demonstrated the reproducible large-scale production of exosomes derived from adipose tissue-derived MSC (ASC-exosomes) using TFF and the lifesaving effect of the ASC-exosomes in a lethal model of cisplatin-induced rat AKI. Our results suggest the possibility of large-scale stable production of ASC-exosomes without loss of function and their successful application in life-threatening diseases.

The protective effect and mechanism of lentinan on acute kidney injury in septic rats.

This study aimed to investigate the protective effect and mechanism of lentinan (LNT) on acute kidney injury (AKI) in septic rats. A total 72 male SD rats were randomly divided into 6 groups with 12 rats in each group. Except for the sham group, all groups, including the burn sepsis group (BS group), the positive drug control group (dexamethasone, 5 mg/kg, PC group), the LNT low-concentration group (LNT-L group) (50 mg/kg), the LNT medium-concentration group (LNT-M group) (100 mg/kg), and the LNT high-concentration group (LNT-H group) (200 mg/kg), were intraperitoneally injected with the same amount of normal saline 30 min before injury. The levels of serum interleukin (IL)-4, IL-6, IL-10, and tumor necrosis factor alpha (TNF-α); the indexes of blood urea nitrogen (BUN) and creatinine (Cr); and the protein expression levels of inducible nitric oxide synthase (iNOS), intercellular adhesion molecule 1 (ICAM-1), and nuclear factor-κB (NF-κB) in renal tissue were detected 24 hours after the model was established. Compared with the sham group, the BUN and Cr of the other groups were significantly higher, while those of the LNT group with different concentrations were significantly lower than those of the BS group (P<0.05). Compared with the sham group, the protein expression levels of NF-κB, iNOS, and ICAM-1 along with the levels of pro-inflammatory factors TNF-α and IL-6 in serum were significantly increased, while the levels of anti-inflammatory factors IL-4 and IL-10 were obviously lower in the BS group. Compared with the BS group, the protein expression levels of NF-κB, iNOS, and ICAM-1 along with the levels of pro-inflammatory factors TNF-α and IL-6 in serum were significantly decreased, while the levels of anti-inflammatory factors IL-4 and IL-10 were obviously increased in the LNT group with different concentrations.. LNT has a certain protective effect on AKI in septic rats, and its mechanism may involve inhibiting the activation of NF-κB, which suppresses the expression of proinflammatory factors in turn, thus promoting the release of anti-inflammatory factors.

MiR-20a Promotes kidney injury in sepsis rats through autophagy.

The aim of this work was to study the effects of micro ribonucleic acid (miR)-20a on acute kidney injury (AKI) in sepsis rats and its key molecular mechanism. Sprague-Dawley rats were randomly divided into healthy rat group (H group, n=3), sham group (S group, n=3), sepsis rat group (D group, n=3), sepsis rat + negative control transfection group (N group, n=3) and sepsis rat + miR-20a inhibitor transfection group (M group, n=3). At 6 h, 12 h and 24 h, serum creatinine (Scr) and blood urea nitrogen (BUN) were detected, the changes in miR-20a expression in kidney tissues were determined via reverse transcription-polymerase chain reaction (RT-PCR), the expression of autophagy marker protein microtubule-associated protein 1 light chain 3 (LC3) was measured via Western blotting, and the inflammatory cell infiltration in kidney tissues was detected using hematoxylin-eosin (HE) staining. There was no obvious change in each index in S group compared with H group. D group, N group and M group had higher levels of Scr, BUN and LC3 in kidney tissues than S group. The levels of Scr, BUN and LC3 in kidney tissues were lower in M group than those in N group. MiR-20a may cause AKI in sepsis rats via activating autophagy.

A novel role of the miR-152-3p/ERRFI1/STAT3 pathway modulates the apoptosis and inflammatory response after acute kidney injury.

Acute kidney injury (AKI) is one of the most common and serious complications in the development of sepsis. Many microRNAs are closely related to the occurrence, development, and prognosis of sepsis AKI (but the effect and mechanism of miR-152-3p in it is unclear). Meanwhile, the ERBB receptor feedback inhibitor 1 (ERRFI1) has a negative regulatory effect on signal transducer and activator of transcription 3 (STAT3) phosphorylation on uterine epithelial cells. But, the relationship between miR-152-3p and renal function, inflammatory factors, prognosis in AKI, and the mechanism is not clear. Analyzing sepsis-induced AKI rats and the cell model, our results revealed that miR-152-3p was upregulated in septic AKI patients and positively correlated with serum creatinine, urea nitrogen, interleukin 1β (IL-1β) and tumor necrosis factor α (TNF-α). Downregulation of miR-152-3p with the inhibitor could dramatically attenuate caspase-3, bromodeoxyuridine and IL-1β, and TNF-α in the AKI rats' model. Furthermore, downregulation of miR-152-3p attenuated lipopolysaccharide-induced apoptosis and inflammatory response in HK-2 and HEK293 cells. To further explore the mechanisms, we found ERRFI1 was appreciably downregulated and STAT3 was upregulated in AKI, whereas ERRFI1 was radically upregulated and STAT3 was greatly downregulated after the addition of miR-152-3p inhibitor, no matter in vivoorin vitro. Summarily, our study confirmed that miR-152-3p could promote the expression of STAT3 by targeting ERRFI1, aggravate cell apoptosis and inflammatory response, and thereby aggravate kidney injury in sepsis AKI.

Downregulation of XIST ameliorates acute kidney injury by sponging miR-142-5p and targeting PDCD4.

Acute kidney injury (AKI) is a common kidney disease that markedly affects public health. To date, the roles of long noncoding RNA XIST in AKI are poorly understood. Here, we investigated the biological functions of XIST in AKI. We observed that XIST expression increased in patients with AKI and HK-2 cells stimulated by CoCl2 . In addition, a rat AKI model induced by ischemia-reperfusion was established. Tumor necrosis factor-α, interleukin-6, and cyclooxygenase-2 messenger RNA expression were induced in vivo; moreover, XIST expression was upregulated. Knockdown of XIST significantly repressed CoCl2 -triggered injury in HK-2 cells. However, microRNA (miR)-142-5p, a downstream target of XIST, was downregulated in AKI. miR-142-5p was repressed by XIST and miR-142-5p could inhibit CoCl2 -induced injury in HK-2 cells. Moreover, PDCD4 expression was significantly increased in AKI. PDCD4 was predicted to be the target of miR-142-5p. Subsequently, loss of PDCD4 was able to retard injury in HK-2 cells exposed to CoCl2. Thus, we suggest that XIST regulates miR-142-5p and PDCD4, and it has the potential to function as a biomarker in therapeutic strategies for AKI.

LINC00963 targeting miR-128-3p promotes acute kidney injury process by activating JAK2/STAT1 pathway.

The role of long non‐coding RNAs (lncRNAs) in kidney diseases has been gradually discovered in recent years. LINC00963, as an lncRNA, was found to be involved in chronic renal failure. However, the role and molecular mechanisms of LINC00963 engaged in acute kidney injury (AKI) were still unclear. In this study, we established rat AKI models by ischaemia and reperfusion (I/R) treatment. Urea and creatinine levels were determined, and histological features of kidney tissues were examined following HE staining. CCK8 assay was chosen to assess the viability of hypoxia‐induced HK‐2 cells. Dual‐luciferase reporter gene assays were performed to verify the target relationship between LINC00963 and microRNA. The mRNA and protein levels were assayed by RT‐qPCR and Western blot, respectively. Annexin V‐FITC/PI and TUNEL staining were used to evaluate apoptosis. LINC00963 was highly expressed in the cell and rat models, and miR‐128‐3p was predicted and then verified as a target gene of LINC00963. Knockdown of LINC00963 reduced acute renal injury both in vitro and in vivo. LINC00963 activated the JAK2/STAT1 pathway to aggravate renal I/R injury. LINC00963 could target miR‐128‐3p to reduce G1 arrest and apoptosis through JAK2/STAT1 pathway to promote the progression of AKI.

Dexmedetomidine Protects against Ischemia and Reperfusion-Induced Kidney Injury in Rats.

Acute kidney injury (AKI), a clinical syndrome, is a sudden onset of kidney failure that severely affects the kidney tubules. One potential treatment is dexmedetomidine (DEX), a highly selective α2-adrenoreceptor agonist that is used as an anesthetic adjuvant. It also has anti-inflammatory, neuroprotective, and sympatholytic qualities. The aim of this study was to establish whether DEX also offers protection against ischemia and reperfusion- (I/R-) induced AKI in rats. An intraperitoneal injection of DEX (25 μg/kg) was administered 30 min prior to the induction of I/R. The results indicate that in the I/R rats, DEX played a protective role by reducing the damage to the tubules and maintaining renal function. Furthermore, in response to I/R, the DEX treatment reduced the mRNA expression of TNF-α, IL-1β, IL-6, and MCP-1 in the kidney tissues and the serum levels of TNF-α, IL-1β, IL-6, and MCP-1. DEX also reduced the levels of oxidative stress and apoptosis in the tubular cells. These results indicate that in response to I/R kidney injury, DEX plays a protective role by inhibiting inflammation and tubular cell apoptosis, reducing the production of reactive oxygen species, and promoting renal function.

Ramipril Blunt Glycerol‐induced Acute Renal Failure in Rats Through its Anti‐apoptosis, Anti‐inflammatory, Anti‐oxidant, and Renin‐inhibiting Properties

Acute Kidney Injury (AKI) is a sudden episode of kidney failure or kidney damage that happens within a few hours or a few days and causes a buildup of waste products in the blood making it hard for the kidney to keep the right balance of fluid in the body. It affects other organs such as the heart, brain and lungs (Schrier et al., 2004). Renal tubular damage is a pathological characteristic of AKI. 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. Studies have demonstrated that the pathogenesis of glycerol‐induced AKI involves myoglobin toxicity [Gburek et al 2003; Reeder and Wilson 2005], reactive oxygen species (ROS) [Wu et al 2017], inflammation [ Al Asmari et al 2017], apoptosis [Wang et al 2011] and redox‐active iron [Wu et al 2017].In this study ramipril and pioglitazone (reference drug) were evaluated for their potential therapy in glycerol‐induced AKI in rats. 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, NK‐KB, and KIM‐1 were carried out.Results from this study show 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. Histopathologically, there were massive infiltration of leucocytes and congestion of the kidney in toxicant group, but the ramipril treated group showed a milder condition. In immunohistochemistry, the two drugs significantly inhibited the expressions of the four proteins, which were highly expressed in the toxicant group.This study thus showed that ramipril and pioglitazone have nephroprotective effect and thus has ability to blunt acute kidney injury through their anti‐inflammatory, anti‐apoptosis, anti‐renin and anti‐oxidant properties.Support or Funding InformationThis study was supported with a grant (TETFUND/DESS/NRF/UI IBADAN/STI/VOL. 1/B2.20.11) received from the National Research Foundation of the Tertiary Education Trust Fund (TETFUND), Abuja, Nigeria.

Inhibition of Ferroptosis Attenuates Acute Kidney Injury in Rats with Severe Acute Pancreatitis

Acute kidney injury (AKI) is a frequent complication of severe acute pancreatitis (SAP). Ferroptosis is involved in a range of diseases. However, the role of ferroptosis in SAP-induced AKI has yet to be elucidated. We aimed to investigate whether ferroptosis is induced in the kidney after SAP and whether inhibition of ferroptosis ameliorates AKI in a rat model of SAP. Sodium taurocholate (5%) was retrogradely perfused into the biliopancreatic duct to establish a model of SAP with AKI in rats. The levels of serum amylase, lipase, tumor necrosis factor (TNF)-α, interleukin (IL)-6, creatinine (Cr) and blood urea nitrogen (BUN) in rats were measured. We also determined the biochemical and morphological changes associated with ferroptosis in renal tissue, including iron accumulation, lipid peroxidation assays, and mitochondrial shrinkage. H&E staining was used to assess pancreatic and renal histological changes. Western blot analysis, RT-PCR, and immunofluorescence staining were performed to analyze the expression of ferroptosis-related proteins and genes. SAP-induced AKI was followed by iron accumulation, increased lipid peroxidation, and upregulation of ferroptosis-related proteins and genes. Twenty-four hours after SAP, TEM confirmed the presence of typical shrunken mitochondria. Furthermore, treatment with liproxstatin-1 lowered the levels of serum amylase, TNF-α, IL-6, Cr and BUN, decreased kidney lipid peroxidation and alleviated pancreatic and renal histopathology injury in SAP rats. Our findings are the first to demonstrate the involvement of ferroptosis in SAP-associated renal damage and present ferroptosis as a therapeutic target for effective treatment of SAP-induced AKI.

The role of activated NLRP3 inflammatory body in acute kidney injury in rats caused by sepsis and NLRP3-TXNIP signaling pathway.

ObjectiveThe model of acute renal injury (AKI) induced by sepsis in rats was established by abdominal resection through surgical suture. The activation mechanism of nod-like receptor with pyrin domain containing 3 (NLRP3) inflammatory corpuscle in AKI induced by sepsis was analyzed.MethodsHere, 60 male rats were selected and divided into two groups, including sham-operated group (NO-OPs group, n = 15) and sepsis group (CELP group, n = 45). In order to examine each index of CELP group, four time points (10, 20, 30, and 40 h) were set as control. In NO-OPs group, only abdominal resection through surgical suture was carried out. The expression levels of NLRP3, apoptosis-associated speck-like protein containing a C-terminal caspase recruitment domain (ASC), caspase-1, and the expression level of NLRP3-TXNIP signaling pathway were measured by immunohistochemistry, Western blotting, immunoprecipitation, and mito-TEMPO (a mitochondria-targeted antioxidant) 40 h after operation and 10, 20, 30, and 40 h post-operation in CELP group. Herein, 40 h post-operation in NO-OPs group and 10, 20, 30, and 40 h post-operation in CELP group, peripheral blood samples were collected.ResultsCompared with NO-OPs group, the levels of serum creatinine (Scr) and blood urea nitrogen (BUN) in CELP group were increased (P < 0.05). Compared with NO-OPs group, the expression levels of interleukin-1β (IL-1β), NLRP3, ASC, and caspase-1 in CELP group were increased (P < 0.05). The expression level of TXNIP in renal tubular epithelial cells in rats was up-regulated. There was a positive correlation between TXNIP and NLRP3. The binding of NLRP3-TXNIP signaling pathway could be inhibited by siRNA transfection or mito-TMPO, and the activity of NLRP3 inflammatory bodies could be inhibited as well.ConclusionActivation of NLRP3 inflammatory corpuscles could promote AKI induced by sepsis. Simultaneously, renal injury may lead to the production of mitochondrial reactive oxygen species (mROS), which may induce the binding of TXNIP to NLRP3.

Aquaporin 1 alleviates acute kidney injury via PI3K-mediated macrophage M2 polarization.

Lipopolysaccharide (LPS)-induced acute kidney injury (AKI) is associated with an abnormal immune response. Accumulating evidence has demonstrated that aquaporin 1 (AQP1) prevents kidney tissue injury in LPS-induced AKI by mediating immune response. However, the underlying mechanisms remain obscure. Macrophages as immune cells with multiple phenotypes are important mediators in tissue homeostasis and host defense. We propose that macrophage polarization is implicated in AQP1-mediated immune response. Herein we established sepsis-induced AKI model rats through intraperitoneal injection of LPS into Wistar rats to reveal immune mechanism of damage. We also used LPS-induced mouse RAW264.7 cells to elucidate the molecular mechanism of macropage polarization. Histopathology showed that renal tubular epithelial cells in the model group were swollen, inflammatory exudation was obvious and the inflammatory factors, interleukin-6 (IL-6) and tumor necrosis factor α (TNF-α) were increased. Western blotting showed PI3K was upregulated in the model group. Serum creatinine and urea nitrogen increased after LPS injection. Renal AQP1 mRNA is downregulated and serum AQP1 protein increased first and then decreased in LPS-induced AKI rats. M2 macrophage markers (Arg-1, CD206) were increased in repair stage. In addition, treatment of murine macrophages (RAW264.7) with AQP1 siRNA resulted in decreased PI3K activation and M2 polarization, but increased IL-6 and TNF-α. Moreover, inhibiting PI3K with wortmannin imitated the results of AQP1 silencing. Macrophage M2 polarization is likely the cellular mechanism underlying the anti-AKI property of AQP1, and PI3K activation is involved in the AQP1-induced M2 phenotype switch.

CircMTO1 Attenuated Acute Kidney Injury Through Regulating miR-337

Acute kidney injury (AKI) is an independent risk factor for the increased risk of death in patients with sepsis. In the current study, we first investigated the expression of circMTO1 in sepsis-induced AKI, and the underlying mechanism was further elucidated. The results showed that circMTO1 expression level was significantly decreased in serums and kidney tissues of US rats and RMCs treated with LPS. Besides, circMTO1 overexpression promoted cell viability, suppressed cell apoptosis and cytokines production of LPS-treated RMCs. Bioinformatics analysis showed that circMTO1 served as a sponge for miR-337. Furthermore, circMTO1 could inhibit the expression of KLF6. Altogether, our study first reported that circMTO1 expression was decreased in sepsis-induced AKI rat models and RMCs treated with LPS. CircMTO1 overexpression could attenuate AKI development by sponging miR-337 and regulating KLF6 expression, which may provide new ideas for evaluation the pathogenesis and the treatment of sepsis-induced AKI.

Comparative nephroprotective effects of curcumin and etoricoxib against cisplatin-induced acute kidney injury in rats

ObjectiveAlthough cisplatin (CIS) acts as potent chemotherapy, nephrotoxicity still its major life-threatening side effect. The purpose of this study was to discuss and compare the renoprotective effects of curcumin (CUR) and etoricoxib (ETB) against CIS-induced nephrotoxicity. Materials & methodsThirty six adult female rats were divided equally into 6 groups: Group I (control), Group II (CIS) received cisplatin (7.5 mg/kg i.p), Group III (CUR) and group IV (ETB) received curcumin (200 mg/kg/day) or etoricoxib (10 mg/kg/day) respectively via gavage for seven continuous days. Group V (CIS + CUR) and Group VI (CIS + ETB) received curcumin (200 mg/kg/day) or etoricoxib (10 mg/kg/day) via gavage for seven continuous days. On the 4th day, the rats received cisplatin (7.5 mg/kg i.p) as a single injection 1 h after last curcumin or etoricoxib administration. At the assigned time, blood and tissue samples were collected for biochemical, histochemical, histopathological, immunohistochemical, and RT-PCR gene expression studies. ResultsCurcumin administration significantly decreased CIS-induced elevation of serum creatinine and blood urea nitrogen (BUN), and reversed oxidative stress markers; glutathione (GSH) and malondialdehyde (MDA) to control level. Suppression of inflammatory and apoptotic responses by CUR co-treatment was evidenced by decreased iNOS and BAX immunohistochemical reactions, and TNF-α and Caspase3 gene expressions which were detected by RT-PCR in kidney tissues. To our knowledge, this is the first time to discuss the effect of ETB on CIS induced nephrotoxicity. Although ETB reduced the previously mentioned inflammatory and apoptotic markers, its effect was less than that of CUR. Administration of ETB couldn’t modify the disturbed levels of creatinine, BUN, GSH, and MDA. ConclusionIn conclusion, CUR provided a promising renoprotective effect against CIS induced nephrotoxicity. Further studies are recommended to approve or disapprove the protective role of ETB in CIS induced nephrotoxicity.