Celecoxib modulates nitric oxide and reactive oxygen species in kidney ischemia/reperfusion injury and rat aorta model of hypoxia/reoxygenation

Evaluation of gastric tolerability for long-term use of diclofenac and celecoxib in male albino rats and potential gastroprotective benefits of royal jelly: a randomized controlled trial

OBJECTIVES

Nonsteroidal anti-inflammatory drugs (NSAIDs) are used for pain and inflammation relief. Our study aimed to explore the ulcerogenic effect of long-term diclofenac and celecoxib administration on male albino stomachs, focusing on the possible gastroprotective effect of royal jelly administration.

METHODS

Five equal groups of 50 male albino rats. The drug dosages were: diclofenac potassium (10 mg/kg/day), celecoxib (50 mg/kg/day), and RJ (300 mg/kg/day), for 4 weeks. Group 1 received no medication. Group 2 received oral diclofenac potassium. Group 3 received oral RJ plus diclofenac potassium. Group 4 received celecoxib orally. Group 4 received oral RJ plus celecoxib. When the experiment was over, rats were euthanized, blood samples were gathered, and stomachs were dissected out. Stomachs were examined for ulcer counts. Serum levels of MDA and SOD were determined. Gastric mucosa contents of MDA, SOD, PGE2, MPO, apoptotic (Bax), and anti-apoptotic (Bcl-2) genes were measured. Gastric tissue was also analyzed histopathologically.

RESULTS

Long-term administration of diclofenac and celecoxib, in such dose and duration, caused each of the aforementioned parameters to significantly deteriorate, with significant improvement with RJ co-administration. Diclofenac developed severe gastric ulcers in group 2, and RJ co-administration significantly reduced the gastric mucosa damage in group 3. Celecoxib developed no gastric ulcer in both groups 4 and 5.

CONCLUSIONS

Long-term use of diclofenac in male albino rats caused severe gastric ulcers with significant gastroprotective effects of RJ. Celecoxib provides preferable GI tolerability; thus, it should be prescribed for patients at increased risk of gastrointestinal bleeding requiring NSAIDs.

Anti-toxoplasmic effects of celecoxib alone and combined with spiramycin in experimental mice

Even though toxoplasmosis is a worldwide parasitic disease caused by Toxoplasma gondii (T. gondii), the available drugs used for the treatment of symptomatic toxoplasmosis have multiple drawbacks. So, there is a considerable need to discover new potential therapeutic agents. The current study aimed to assess the effect of celecoxib (CELE) alone or combined with spiramycin against chronic toxoplasmosis in experimentally infected mice. The study documented the reduction rate of T. gondii cysts in brain tissues and ultrastructural changes through transmission electron microscopy after treatment. We also investigated pathological changes in the brain, liver, lung, and spleen, as well as the expression of TGF-β, iNOS, and pSTAT-1 in brain tissues. Other markers for kidney function and serum levels of interleukins 10 and 12 were also assessed. The study reported a reduction rate of T. gondii brain cyst count of 32.9 % after CELE treatment, 71.7 % after spiramycin treatment, and 75.7 % after combined treatment. Furthermore, the CELE and spiramycin combination improved the ultrastructure and histopathology in brain tissues while decreasing TGF-β, iNOS, and pSTAT-1 expression. The combined therapy ameliorated the inflammation of the liver, lung, and spleen, upregulated the IL-12 level, reduced the IL-10 level, and was accompanied by a reduction in creatinine and urea in serum. In conclusion, CELE increased spiramycin therapeutic efficacy, and their combination showed a better response than spiramycin alone. Thus, the CELE combination with spiramycin represents a hopeful therapy against chronic toxoplasmosis.

Discovery of ferroptosis-related genes in renal ischemia reperfusion and evaluate the potential impact on kidney transplantation

Background

Renal ischemia reperfusion injury (IRI) is one of the pivotal event of acute kidney injury (AKI), and they are unavoidable in the process of kidney transplantation, which eventually leads to the loss of renal allograft. Ferroptosis is a newly identified programmed cell death. Recent studies have suggested that ferroptosis may participate in the pathophysiological process of renal IRI. Therefore, we aimed to determine biomarkers associated with ferroptosis during renal IRI and their impact on renal allografts.

Methods

We conducted a comprehensive bioinformatics analysis and established an IRI-AKI animal model to illustrate the critical role of ferroptosis-related hub genes (FRHGs) in IRI-AKI and their potential impact on kidney transplantation.

Results

In this study, we identified 60 ferroptosis-related genes (FRGs) in renal IRI based on the GSE148420 dataset and FerrDb database. And then we performed functional annotation analysis using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment. Protein-protein interaction (PPI) network was constructed by online tool String. EZH2, CDKN1A, PPARA, EGR1, ATF3, and CD44 were identited as six ferroptosis-related hubgenes (FRHGs) using four methods, including MMC, Degree, DMNC, and EPC. FRHGs expression level were verified by the validation sets GSE58438 and GSE126805. Protein expression level of FRHGs verified by Proteomics and Western blot. Cibersort was utilized to analyze immune cell infiltration during renal IRI as well as the correlation between FRHGs and immune cells. The GSE21374 dataset was used for renal allografts survival analysis. Finally, We induced the IRI-AKI animal model and illustrated the importance of FRGHs CD44 in ferroptosis and the accumulation of macrophages.

Conclusion

We identified 6 FRHGs. We found that FRHGs not only exhibited significant correlation with immune cells but also directly influenced the survival of transplanted kidneys in the human population. Among six FRHGs, only CD44 was overexpressed at both the gene and protein levels. Anti-CD44 exerts a protective effect by inhibiting ferroptosis and the accumulation of M1 macrophages during renal IRI. This study provided new insights into the pathogenesis of renal IRI and provided new evidence for its treatment.

Small extracellular vesicles from HO-1-modified bone marrow-derived mesenchymal stem cells attenuate ischemia-reperfusion injury after steatotic liver transplantation by suppressing ferroptosis via miR-214-3p

Donor shortage is a major problem that limits liver transplantation availability. Steatotic donor liver presents a feasible strategy to solve this problem. However, severe ischemia-reperfusion injury (IRI) is an obstacle to the adoption of steatotic transplanted livers. Evidence from our prior studies indicated that bone marrow mesenchymal stem cells modified with heme oxygenase-1 (HMSCs) can attenuate non-steatotic liver IRI. However, the contribution of HMSCs in transplanted steatotic liver IRI is unclear. Here, HMSCs and their derived small extracellular vesicles (HM-sEVs) alleviated IRI in transplanted steatotic livers. After liver transplantation, there was significant enrichment of the differentially expressed genes in the glutathione metabolism and ferroptosis pathways, accompanied by ferroptosis marker upregulation. The HMSCs and HM-sEVs suppressed ferroptosis and attenuated IRI in the transplanted steatotic livers. MicroRNA (miRNA) microarray and validation experiments indicated that miR-214-3p, which was abundant in the HM-sEVs, suppressed ferroptosis by targeting cyclooxygenase 2 (COX2). In contrast, COX2 overexpression reversed this effect. Knockdown of miR-214-3p in the HM-sEVs diminished its ability to suppress ferroptosis and protect liver tissues/cells. The findings suggested that HM-sEVs suppressed ferroptosis to attenuate transplanted steatotic liver IRI via the miR-214-3p-COX2 axis.

Effect of Celecoxib and Infliximab against Multiple Organ Damage Induced by Sepsis in Rats: A Comparative Study

In cases of sepsis, the immune system responds with an uncontrolled release of proinflammatory cytokines and reactive oxygen species. The lungs, kidneys, and liver are among the early impacted organs during sepsis and are a direct cause of mortality. The aim of this study was to compare the effects of infliximab (IFX) and celecoxib (CLX) on septic rats that went through a cecal ligation and puncture (CLP) surgery to induce sepsis. This study included four groups: sham, CLP (untreated), and CLP-treated with CLX or IFX. The administration of “low dose” CLX or IFX was performed after 2 h following the induction of sepsis. Twenty-four hours following the induction of sepsis, the rats were sacrificed and blood samples were collected to evaluate kidney, liver, and lung injuries. MDA and NOx content, in addition to SOD activity and GSH levels, were evaluated in the tissue homogenates of each group. Tissue samples were also investigated histopathologically. In a separate experiment, the same groups were employed to evaluate the survival of septic rats in a 7-day observation period. The results of this study showed that treatment with either CLX or IFX ameliorated the three organs’ damage compared to septic-untreated rats, decreased oxidative stress, enhanced the antioxidant defense, and reduced serum cytokines. As a result, a higher survival rate resulted: 62.5% and 37.5% after the administration of CLX and IFX, respectively, compared to 0% in the CLP group after 7 days. No significant differences were observed between the two agents in all measured parameters. Histopathological examination confirmed the observed results. In conclusion, CLX and IFX ameliorated lung, kidney, and liver injuries associated with sepsis through anti-inflammatory and antioxidant actions, which correlated to the increase in survival observed with both of them.

Therapeutic implications of cyclooxygenase (COX) inhibitors in ischemic injury

INTRODUCTION

Ischemia-reperfusion injury (IRI) is the inexplicable aggravation of cellular dysfunction that results in blood flow restoration to previously ischemic tissues. COX mediates the oxidative conversion of AA to various prostaglandins and thromboxanes, which are involved in various physiological and pathological processes. In the pathophysiology of I/R injuries, COX has been found to play an important role. I/R injuries affect most vital organs and are characterized by inflammation, oxidative stress, cell death, and apoptosis, leading to morbidity and mortality.

MATERIALS AND METHODS

A systematic literature review of Bentham, Scopus, PubMed, Medline, and EMBASE (Elsevier) databases was carried out to understand the Nature and mechanistic interventions of the Cyclooxygenase modulations in ischemic injury. Here, we have discussed the COX Physiology and downstream signalling pathways modulated by COX, e.g., Camp Pathway, Peroxisome Proliferator-Activated Receptor Activity, NF-kB Signalling, PI3K/Akt Signalling in ischemic injury.

CONCLUSION

This review will discuss the various COX types, specifically COX-1 and COX-2, which are involved in developing I/R injury in organs such as the brain, spinal cord, heart, kidney, liver, and intestine.

Low-dose cyclooxygenase-2 (COX-2) inhibitor celecoxib plays a protective role in the rat model of neonatal necrotizing enterocolitis

This study aims to investigate the effects of the cyclooxygenase-2 (COX-2) inhibitor celecoxib on neonatal necrotizing enterocolitis (NEC) in rats. After treatment with a low dose of celecoxib (0.5, 1, or 1.5 mg/kg), pathological changes in the ileum and the levels of oxidative stress and inflammatory factors in NEC rats were compared. Enzyme-linked immunosorbent assay (ELISA) was employed to detect inflammatory factors, terminal deoxyribonucleotidyl transferase (TdT)-mediated biotin-16-dUTP nick-end labeling (TUNEL) staining was employed to assess apoptotic epithelial cells in the ileum, and real-time quantitative polymerase chain reaction (qRT-PCR) and Western blotting were used to quantify gene and protein expression, respectively. The incidences of NEC rats in the 0.5, 1 and 1.5 mg/kg celecoxib groups were lower than in the model group (100%). Celecoxib improved the histopathology of the ileum in NEC rats. Moreover, low doses of celecoxib relieved oxidative stress and inflammation in NEC rats, as evidenced by decreased tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), total oxidation state (TOS), malondialdehyde (MDA) and oxidative stress index (OSI), as well as increased interleukin-10 (IL-10), total antioxidant status (TAS), superoxide dismutase (SOD) and glutathione peroxidase (GPx). With increasing celecoxib doses (0.5, 1, or 1.5 mg/kg), the amount of apoptotic epithelial cells in the ileum of NEC rats gradually declined and Caspase-3 expression was reduced. The low dose of the COX-2 inhibitor celecoxib ameliorated the histopathologic conditions of the ileum, alleviated oxidative stress and inflammation, and reduced apoptotic epithelial cells in NEC rats, thereby making it a potential therapy for NEC.

Targeting Inflammation and Oxidative Stress as a Therapy for Ischemic Kidney Injury

Inflammation and oxidative stress are the main pathological processes that accompany ischemic injury of kidneys and other organs. Based on this, these factors are often chosen as a target for treatment of acute kidney injury (AKI) in a variety of experimental and clinical studies. Note, that since these two components are closely interrelated during AKI development, substances that treat one of the processes often affect the other. The review considers several groups of promising nephroprotectors that have both anti-inflammatory and antioxidant effects. For example, many antioxidants, such as vitamins, polyphenolic compounds, and mitochondria-targeted antioxidants, not only reduce production of the reactive oxygen species in the cell but also modulate activity of the immune cells. On the other hand, immunosuppressors and non-steroidal anti-inflammatory drugs that primarily affect inflammation also reduce oxidative stress under some conditions. Another group of therapeutics is represented by hormones, such as estrogens and melatonin, which significantly reduce severity of the kidney damage through modulation of both these processes. We conclude that drugs with combined anti-inflammatory and antioxidant capacities are the most promising agents for the treatment of acute ischemic kidney injury.

Effect of celecoxib in treatment of burn-induced hypermetabolism

Background: Cyclooxygenase-2 (COX-2) catalyzes the rate-limiting step of prostanoid biosynthesis. Under pathologic conditions, COX-2 activity can produce reactive oxygen species and toxic prostaglandin metabolites that exacerbate injury and metabolic disturbance. The present study was performed to investigate the effect of Celecoxib (the inhibitor of COX-2) treatment on lipolysis in burn mice.

Methods: One hundred male BALB/c mice were randomly divided into sham group, burn group, celecoxib group, and burn with celecoxib group (25 mice in each group). Thirty percent total body surface area (TBSA) full-thickness injury was made for mice to mimic burn injuries. Volume of oxygen uptake (VO₂), volume of carbon dioxide output (VCO₂), respiratory exchange ratio (RER), energy expenditure (EE), COX-2 and uncoupled protein-1 (UCP-1) expression in brown adipose tissue (BAT) were measured for different groups.

Results: Adipose tissue (AT) activation was associated with the augmentation of mitochondria biogenesis, and UCP-1 expression in isolated iBAT mitochondria. In addition, VO₂, VCO₂, EE, COX-2, and UCP-1 expression were significantly higher in burn group than in burn with celecoxib group (P<0.05).

Conclusion: BAT plays important roles in burn injury-induced hypermetabolism through its morphological changes and elevating the expression of UCP-1. Celecoxib could improve lipolysis after burn injury.

Kappa-opioid receptor agonist U50448H protects against renal ischemia-reperfusion injury in rats via activating the PI3K/Akt signaling pathway

Renal ischemia-reperfusion injury (IRI) is regarded as a leading cause of acute kidney failure and renal dysfunction. Previous studies show that kappa opioid receptor (KOR) agonists can attenuate IRI in cardiomycytes and neuronal cells. In this study we explored the effects of a KOR agonist on renal IRI and the underlying mechanisms in vivo and in vitro. An IRI model was established in SD rats, which were intravenously pretreated with a KOR agonist U50448H (1 mg/kg), a KOR antagonist Nor-BNI (2 mg/kg) followed by U50448H (1 mg/kg), or the PI3K inhibitor wortmannin (1.4 mg/kg) followed by U50448H (1 mg/kg). U50448H pretreatment significantly decreased the serum levels of creatinine (Cr) and BUN, the renal tubular injury scores and the apoptotic index (AI) in IRI model rats. Furthermore, U50448H significantly increased SOD activity and NO levels, and reduced the MDA levels in the kidney tissues of IRI model rats. Moreover, U50448H significantly increased the phosphorylation of Akt, eNOS and PI3K in the kidney tissues of IRI model rats. All the beneficial effects of U50448H were blocked by Nor-BNI or wortmannin pre-administered. Similar results were observed in vitro in renal tubular epithelial NRK-52E cells subjected to a hypoxia-reoxygenation (HR) procedure. Our results demonstrate that the KOR agonist U50448H protects against renal IRI via activating the PI3K/Akt signaling pathway.

Anti-aging effect of fullerenol on skin aging through derived stem cells in a mouse model

Fullerenol is similar to graphite in terms of structure. In the present study, the anti-aging effect of fullerenol on skin through derived stem cells in a mouse model was assessed and the potential mechanism of fullerenol was investigated. The anti-aging effect of fullerenol effectively inhibited the retention rate of transplanted adipose-derived stem cells and increased the thickness of the dermal portion of skin and collagen ratio in mice. The effect of fullerenol on the proliferation of stem cells was observed. Treatment with fullerenol effectively promoted the mRNA expression of Runt-related transcription factor 2, alkaline phosphatase and osteocalcin in a mouse model of skin aging induced by D-galactose. However, fullerenol treatment effectively suppressed the protein expression of peroxisome proliferator-activated receptor-γ (PPAR-γ) and increased forkhead box protein O1 (FoxO1) protein expression in the mice model of skin aging induced by D-galactose. These results demonstrate that the anti-aging effect of fullerenol on skin through derived stem cells may be mediated in mice via the PPAR-γ/FoxO1 signaling pathway.

Cyclooxygenase-2 Inhibition Limits Angiotensin II-Induced DNA Oxidation and Protein Nitration in Humans

Compared to other cyclooxygenase-2 inhibitors, celecoxib is associated with a lower cardiovascular risk, though the mechanism remains unclear. Angiotensin II is an important mediator of oxidative stress in the pathophysiology of vascular disease. Cyclooxygenase-2 may modify the effects of angiotensin II though this has never been studied in humans. The purpose of the study was to test the effects of selective cyclooxygenase-2 inhibition on plasma measures of oxidative stress, the vasoconstrictor endothelin-1, and nitric oxide metabolites, both at baseline and in respose to Angiotensin II challenge in healthy humans. Measures of 8-hydroxydeoxyguanosine, advanced oxidation protein products, nitrotyrosine, endothelin-1, and nitric oxide metabolites were assessed from plasma samples drawn at baseline and in response to graded angiotensin II infusion (3 ng/kg/min × 30 min, 6 ng/kg/min × 30 min) before and after 14 days of cyclooxygenase-2 inhibition in 14 healthy subjects (eight male, six female) in high salt balance, a state of maximal renin angiotensin system suppression. Angiotensin II infusion significantly increased plasma oxidative stress compared to baseline (8-hydroxydeoxyguanosine; +17%; advanced oxidation protein products; +16%), nitrotyrosine (+76%). Furthermore, levels of endothelin-1 levels were significantly increased (+115%) and nitric oxide metabolites were significantly decreased (−20%). Cycloxygenase-2 inhibition significantly limited the increase in 8-hydroxydeoxyguanosine, nitrotyrosine and the decrease in nitric oxide metabolites induced by angiotensin II infusion, though no changes in advanced oxidation protein products and endothelin-1 concentrations were observed. Cyclooxygenase-2 inhibition with celecoxib partially limited the angiotensin II-mediated increases in markers of oxidative stress in humans, offering a potential physiological pathway for the improved cardiovascular risk profile of this drug.

Celecoxib mitigates genotoxicity induced by ionizing radiation in human blood lymphocytes

Ionizing radiation causes DNA damage and chromosome abbreviations on normal cells. The radioprotective effect of celecoxib (CLX) was investigated against genotoxicity induced by ionizing radiation in cultured human blood lymphocytes. Peripheral blood samples were collected from human volunteers and were incubated at different concentrations at 1, 5, 10 and 50 μM of CLX for two hours. At each dose point, the whole blood was exposed in vitro to 150 cGy of X-ray, and then the lymphocytes were cultured with mitogenic stimulation to determine the micronucleus frequency in cytokinesis blocked binucleated lymphocytes. Incubation of the whole blood with CLX exhibited a significant decrease in the incidence of micronuclei in lymphocytes induced by ionizing radiation, as compared with similarly irradiated lymphocytes without CLX treatment. The maximum reduction on the frequency of micronuclei was observed at 50 μM of CLX (65% decrease). This data may have an important possible application for the protection of human lymphocytes from the genetic damage induced by ionizing irradiation in human exposed to radiation.

Celecoxib administration reduced mortality, mesenteric hypoperfusion, aortic dysfunction and multiple organ injury in septic rats

BACKGROUND

The cyclooxygenase (COX)-2 overexpression is associated with vascular injury and multiple organ failure in sepsis. However, constitutive COX-1 and basal COX-2 expressions have physiological effects. We aimed to investigate the effects of partial and selective COX-2 inhibition without affecting constitutive COX-1 and basal COX-2 activities by celecoxib on mesenteric artery blood flow (MABF), vascular reactivity, oxidative and inflammatory injuries, and survival in septic rats accomplished by cecal ligation and puncture (CLP).

METHODS

Wistar rats were allocated into Sham, CLP, Sham+celecoxib, CLP+celecoxib subgroups. 2h after Sham and CLP operations, celecoxib (0.5mg/kg) or vehicle (saline; 1mL/kg) was administered orally to rats. 18h after drug administrations, MABF and responses of isolated aortic rings to phenylephrine were measured. Tissue samples were obtained for biochemical and histopathological examinations. Furthermore, survival rate was monitored throughout 96h.

RESULTS

Celecoxib ameliorated mesenteric hypoperfusion and partially improved aortic dysfunction induced by CLP. Survival rate was%0 at 49th h in CLP group, but in CLP+celecoxib group it was 42.8% at the end of 96h. Serum AST, ALT, LDH, BUN, Cr and inflammatory cytokine (tumor necrosis factor-alpha, interleukin-1 beta and interleukin-6) levels were increased in CLP group that were prevented by celecoxib. The decreases in liver and spleen glutathione levels and the increases in liver, lung, spleen and kidney malondialdehyde levels in CLP group were blocked by celecoxib. The histopathological protective effects of celecoxib on organ injury due to CLP were also observed.

CONCLUSIONS

Celecoxib has protective effects on sepsis due to its preservative effects on mesenteric perfusion, aortic function and its anti-inflammatory and antioxidative effects.

Renal-targeting triptolide-glucosamine conjugate exhibits lower toxicity and superior efficacy in attenuation of ischemia/reperfusion renal injury in rats

AIM

We previously reported a novel triptolide (TP)-glucosamine conjugate (TPG) that specifically accumulated in kidneys and protected renal function from acute ischemia/reperfusion (I/R) injury in rats. In this study we further examined the molecular mechanisms underlying the renoprotective action of TPG.

METHODS

The renal-targeting of TPG was investigated in a human proximal renal tubular epithelial cell line (HK-2) by measuring cell uptake of TP or TPG. The effects of TP or TPG on cell cycle distribution and apoptosis rate of HK-2 cells were assessed, and the activities of caspase-3 and caspase-9 were also measured. SD rats were subjected to bilateral renal ischemia by temporarily clamping both renal pedicles. The rats were administered TP (4.17 μmol·kg-1·d-1, iv) or TPG (4.17 μmol·kg-1·d-1, iv) for 3 d before the renal surgery. The kidneys were harvested after 24 h of recovery from the surgery. The levels of oxidative stress, proinflammatory cytokines, chemotactic cytokines and intracellular adhesion molecules in kidneys were examined.

RESULTS

The uptake of TPG in HK-2 cells was 2-3 times higher than that of TP at the concentrations tested. Furthermore, TPG targeting the proximal tubules was mediated through interactions with megalin receptors. TP (40-160 nmol/L) concentration-dependently increased G2/M arrest, apoptosis and caspase-3/caspase-9 activity in HK-2 cells, whereas the same concentrations of TPG did not show those features when compared with the control group. In I/R-treated rats, TPG administration caused more robust down-regulation of proinflammatory cytokines (TNF-α, IL-6, IL-1, TGF-β) and chemotactic cytokines (MCP-1) in the kidneys compared with TP administration, suggesting the inhibition of the proliferation and accumulation of lymphocytes. And TPG administration also caused more prominent inhibition on the levels of oxidative stress and intracellular adhesion molecules in the kidneys, compared with TP administration.

CONCLUSION

The renal-targeting TPG is more effective and less toxic than TP, in amelioration of I/R-induced rat renal injury, which may provide a new avenue for the treatment of acute kidney injury.

Renoprotective effect of virgin coconut oil in heated palm oil diet-induced hypertensive rats

Virgin coconut oil, rich in antioxidants, was shown to attenuate hypertension. This study aimed to investigate the effects of virgin coconut oil on blood pressure and related parameters in kidneys in rats fed with 5-times-heated palm oil (5HPO). Thirty-two male Sprague–Dawley rats were divided into 4 groups. Two groups were fed 5HPO (15%) diet and the second group was also given virgin coconut oil (1.42 mL/kg, oral) daily for 16 weeks. The other 2 groups were given basal diet without (control) and with virgin coconut oil. Systolic blood pressure was measured pre- and post-treatment. After 16 weeks, the rats were sacrificed and kidneys were harvested. Dietary 5HPO increased blood pressure, renal thiobarbituric acid reactive substance (TBARS), and nitric oxide contents, but decreased heme oxygenase activity. Virgin coconut oil prevented increase in 5HPO-induced blood pressure and renal nitric oxide content as well as the decrease in renal heme oxygenase activity. The virgin coconut oil also reduced the elevation of renal TBARS induced by the heated oil. However, neither dietary 5HPO nor virgin coconut oil affected renal histomorphometry. In conclusion, virgin coconut oil has a potential to reduce the development of hypertension and renal injury induced by dietary heated oil, possibly via its antioxidant protective effects on the kidneys.

Protective Effect of the Total Flavonoids from Rosa laevigata Michx Fruit on Renal Ischemia-Reperfusion Injury through Suppression of Oxidative Stress and Inflammation

Renal ischemia-reperfusion injury (IRI) is a major cause of acute kidney injury (AKI). Our previous studies have shown that the total flavonoids (TFs) from Rosa laevigata Michx fruit has various activities, however, there were no papers reporting the role of the TFs against renal IRI. In the present work, a hypoxia/reoxygenation (H/R) model in NRK-52E cells and ischemia-reperfusion model in rats were used. The results showed that the TFs significantly attenuated cell injury and markedly decreased serum creatinine (Cr) and blood urea nitrogen (BUN) levels in rats. Further investigation revealed that the TFs markedly decreased the levels of malondialdehyde (MDA), superoxide dismutase (SOD), glutathione (GSH) and glutathione peroxidase (GSH-Px) and intracellular reactive oxygen species (ROS), up-regulated the levels of silent information regulator factor 2-related enzyme 1 (Sirt1), nuclear factor erythroid 2-related factor-2 (Nrf2) and heme oxygenase-1 (HO-1), down-regulated the levels of Kelch like ECH-associated protein-1 (Keap1) and the nuclear translocation of nuclear factor-κBp65 (NF-κBp65), and decreased the mRNA levels of interleukine-1β (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). Furthermore, inhibiting Sirt1 by siRNA showed that the role of the natural product in protecting renal IRI was significantly attenuated, suggesting that the effect of the extract against renal IRI depended on Sirt1. Taken together, the TFs has significantly nephroprotective effect against IRI by affecting Sirt1/Nrf2/NF-κB signaling pathway, which should be developed as a new therapeutic agent or food additives to treat acute kidney injury in the future.

Deficiency of cold-inducible ribonucleic acid-binding protein reduces renal injury after ischemia-reperfusion

BACKGROUND

Renal ischemia-reperfusion injury, commonly caused by major operation and shock, leads to acute kidney injury and is associated with high morbidity and mortality. Cold-inducible ribonucleic acid-binding protein, a cold shock protein, has recently been identified as a damage-associated molecular pattern. We hypothesized that cold-inducible ribonucleic acid-binding protein exacerbates severity of injury in renal ischemia-reperfusion.

METHODS

Renal ischemia was induced in an 8-week-old male C57BL/6 wild-type mice and Cirp(-/-) mice via bilateral clamping of renal pedicles for 30 minutes, followed by reperfusion for 5 or 24 hours and harvest of blood and renal tissue for analysis. Anti-cold-inducible ribonucleic acid-binding protein antibody or non-immunized immunoglobulin G (IgG) was injected intravenously (10 mg/kg body weight) at time of reperfusion.

RESULTS

After renal ischemia-reperfusion, Cirp(-/-) mice demonstrated a reduction of blood urea nitrogen and creatinine of 53% and 60%, respectively, compared with wild-type mice. Serum IL-6 levels were reduced significantly: 70% in Cirp(-/-) mice compared with wild-type mice after renal ischemia-reperfusion. Levels of nitrotyrosine, an oxidatively modified protein marker, and cyclooxygenase-2, an inflammatory mediator, also were significantly decreased in the kidneys of the Cirp(-/-) mice compared with wild-type mice after renal ischemia-reperfusion. Renal caspase-3 activity was decreased in Cirp(-/-) mice compared with wild-type mice after renal ischemia-reperfusion, which corresponded to the reduction of apoptotic cells determined by terminal deoxynucleotidyl transferase dUTP nick-end labeling assay. Injection of neutralizing anti-cold-inducible ribonucleic acid-binding protein antibody into wild-type mice led to an 82% reduction in blood urea nitrogen compared with the vehicle after renal ischemia-reperfusion.

CONCLUSION

Deficiency of cold-inducible ribonucleic acid-binding protein results in less renal injury after renal ischemia-reperfusion by attenuating inflammation and oxidative stress. Furthermore, blockade of cold-inducible ribonucleic acid-binding protein shows a protective effect, indicating cold-inducible ribonucleic acid-binding protein as a target in the treatment of renal ischemia-reperfusion.

Endoplasmic reticulum stress eIF2α-ATF4 pathway-mediated cyclooxygenase-2 induction regulates cadmium-induced autophagy in kidney

The heavy metal cadmium (Cd) is nephrotoxic. Recent studies show that autophagy plays an essential role in Cd-induced kidney injury. However, the mechanisms of Cd-induced kidney injury accompanied by autophagy are still obscure. In the present study, we first confirmed that Cd induced kidney damage and dysfunction, along with autophagy, both in vivo and in vitro. Then, we observed that cyclooxygenase-2 (COX-2) and the eIF2α-ATF4 pathway of endoplasmic reticulum (ER) stress were induced by Cd in both kidney tissues and cultured cells. Further studies showed that inhibition of COX-2 with celecoxib or RNA interference (RNAi) inhibited the Cd-induced autophagy in kidney cells. In addition, blocking ER stress with 4-phenylbutyrate or RNAi partially counteracted COX-2 overexpression and autophagy induced by Cd, which suggested that ER stress was required for Cd-induced kidney autophagy. Significantly, our results showed that Cd activated ATF4 and induced its translocation to the nucleus. Knockdown of ATF4 inhibited Cd-induced COX-2 overexpression. While COX-2 overexpression is involved in renal dysfunction, there is no prior report on the role of COX-2 in autophagy regulation. The results of the current study suggest a novel molecular mechanism that the ER stress eIF2α-ATF4 pathway-mediated COX-2 overexpression contributes to Cd-induced kidney autophagy and injury. The present study implies that COX-2 may be a potential target for therapy against Cd-induced nephrotoxicity.

Honokiol protects against renal ischemia/reperfusion injury via the suppression of oxidative stress, iNOS, inflammation and STAT3 in rats

Honokiol is the predominant active ingredient in the commonly used traditional Chinese medicine, Magnolia, which has been confirmed in previous studies to exhibit anti-oxidation, antimicrobial, antitumor and other pharmacological effects. However, its effects on renal ischemia/reperfusion injury (IRI) remain to be elucidated. The present study aimed to examine the effects of honokiol on renal IRI, and to investigate its potential protective mechanisms in the heart. Male adult Wistar albino rats were induced into a renal IRI model. Subsequently, the levels of serum creatinine, blood urea nitrogen (BUN), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP), and the levels of serum nitrite and the kidney nitrite were examined in the IRI group. The levels of oxidative stress, inducible nitric oxide synthase (iNOS), inflammatory factors and caspase-3 were evaluated using a series of commercially available kits. The levels of phosphorylated signal transducer and activator of transcription 3 (p-STAT3) and the protein expression levels of STAT3 were determined using western blotting. Pretreatment with honokiol significantly reduced the levels of serum creatinine, BUN, ALT, AST and ALP, and the level of nitrite in the kidney of the IRI group, compared with the control group. The levels of malondialdehyde, the activity of myeloperoxidase, and the gene expression and activity of iNOS were reduced in the IRI rats, compared with the sham-operated rats, whereas the levels of superoxide dismutase and catalase were increased following treatment with honokiol in the IRI rats. In addition, the expression levels of tumor necrosis factor-α and interleukin-6 in the IRI rats were increased by honokiol. Treatment with honokiol suppressed the protein expression levels of p-STAT3 and caspase-3 in the IRI rats. These findings indicated that honokiol protects against renal IRI via the suppression of oxidative stress, iNOS, inflammation and STAT3 in the rat.

Dioscin attenuates renal ischemia/reperfusion injury by inhibiting the TLR4/MyD88 signaling pathway via up-regulation of HSP70

We previously reported the effect of dioscin against hepatic ischemia/reperfusion injury (IRI) in rats. However, little is known concerning the role of dioscin in renal IRI. In the present study, rats were subjected to IRI and dioscin was intragastrically administered for seven consecutive days before surgery. In vitro models of hypoxia/reoxygenation were developed in NRK-52E and HK-2 cells, which were prophylactically treated with or without dioscin. The results showed that dioscin significantly decreased serum BUN and Cr levels, and markedly attenuated cell injury. Mechanistic studies showed that dioscin significantly increased HSP70 levels, decreased the levels of TLR4, MyD88, TRAF6, COX-2, JNK, ERK and p38 MAPK phosphorylation, suppressed the nuclear translocation of NF-κB and HMGB1, and subsequently decreased the mRNA levels of IL-1β, IL-6, TNF-α, ICAM-1 and IFN-γ. Moreover, HSP70 siRNA or TLR4 DNA reversed the nephroprotective effects of dioscin, while dioscin still significantly down-regulated the TLR4 signaling pathway. Furthermore, by inhibiting MyD88 with ST2825 (a MyD88 inhibitor), renal IRI was significantly attenuated, suggesting that the effect of dioscin against renal IRI depended on MyD88. Our results suggested that dioscin had a potent effect against renal IRI through suppressing the TLR4/MyD88 signaling pathway by up-regulating HSP70. These data provide new insights for investigating the natural product with the nephroprotective effect against IRI, which should be developed as a new therapeutic agent for the treatment of acute kidney injury in the future.

Effect of NADPH oxidase inhibitor-apocynin on the expression of Src homology-2 domain-containing phosphatase-1 (SHP-1) exposed renal ischemia/reperfusion injury in rats

This study was designed to evaluate whether NADPH oxidase inhibitor (apocynin) preconditioning induces expression of Src homology-2 domain-containing phosphatase-1 (SHP-1) to protect against renal ischemia/reperfusion (I/R) injury (RI/RI) in rats. Rats were pretreated with 50 mg/kg apocynin, then subjected to 45 min ischemia and 24 h reperfusion. The results indicated that apocynin preconditioning improved the recovery of renal function and nitroso-redox balance, reduced oxidative stress injury and inflammation damage, and upregulated expression of SHP-1 as compared to RI/RI group. Therefore our study demonstrated that apocynin preconditioning provided a protection to the kidney against I/R injury in rats partially through inducing expression of SHP-1.

The effect of etoricoxib on kidney ischemia-reperfusion injury in rats: a biochemical and immunohistochemical assessment

The purpose of this study was to investigate the effect of etoricoxib on oxidative injury induced with ischemia-reperfusion (I/R) in rat kidney tissue in terms of biochemistry and immunohistochemistry. Male Albino Wistar rats were divided into renal I/R (RIR), 50 mg/kg etoricoxib+RIR (ETO-50), 100 mg/kg etoricoxib+RIR (ETO-100) and sham operation (SG) groups. Animals in the ETO-50 and ETO-100 groups were given etoricoxib by the oral route at dosages of 50 and 100 mg/kg, respectively. The RIR and SG groups were given distilled water as solvent. One hour after drug administration, 1h of ischemia and 3h of reperfusion were applied to the left kidneys of all rats (apart from SG) under 25 mg/kg thiopental sodium anesthesia. At the end of that time, kidneys were extracted and biochemical and immunohistochemical analyses were performed. Etoricoxib reduced, in a dose-dependent manner, levels of MDA, MPO and COX-2 that normally rise with I/R in rat kidney tissues. Etorixicob did not alter COX-1 activity at 50 and 100 mg/kg doses, but significantly prevented loss of tGSH in tissues with I/R. In addition, Bcl-2' gene expression inhibited with I/R was prevented in renal tubular and glomerular cells. Furthermore, etoricoxib significantly decreased the caspase-3 gene expression which increased with I/R. Etoricoxib significantly prevented I/R injury in a dose-dependent manner. The results of this study show that etoricoxib treatment could decrease kidney injury during IR.