Exploring the role of myeloperoxidase in the atherosclerotic process in hypoxic mice based on the MAPK signaling pathway.

Atherosclerosis (AS) is the common pathophysiological basis of various cardiovascular diseases and the leading cause of death from cardiovascular disease worldwide. When the body is in a hypoxic environment, enhanced oxidative stress and significant accumulation of reactive oxygen species (ROS) in tissue cells exacerbate the inflammatory response, resulting in increased release of myeloperoxidase (MPO), catalyzing the formation of large quantities of hypochlorous acid (HOCl), further oxidative modification of low-density lipoprotein (LDL), and exacerbating the formation and progression of atherosclerotic plaques. The MAPK signaling pathway is important in oxidative stress-mediated promotion of atherogenesis. MPO -/- mice were used in this study to establish a hypoxia model simulating 5000 m altitude and a Western high-fat diet-induced atherosclerosis model for 12 weeks. Exploring the role of MPO in the atherosclerotic process in hypoxic mice by observing the MAPK signaling pathway to provide a therapeutic target for the prevention and treatment of hypoxic atherosclerotic disease in the plateau. We found that hypoxia promotes the formation of atherosclerosis in mice, and the mechanism may be that increased MPO in vivo promotes an inflammatory response, which plays a crucial role in the formation of atherosclerosis. In addition, hypoxia further exacerbates plaque instability by activating the MAPK signaling pathway to upregulate vascular endothelial growth factor (VEGF) and matrix metalloproteinase-9 (MMP9), which in turn promotes angiogenesis within the plaque. Therefore, a potential target for preventing and treating hypoxic atherosclerotic disease is the inhibition of MPO.

Effects of myeloperoxidase on inflammatory responses with hypoxia in Citrobacter rodentium-infectious mice.

PURPOSE: Myeloperoxidase (MPO) has been identified as a mediator in various inflammatory diseases. Bacterial infection of the intestine and hypoxia can both lead to inflammatory responses, but the role of MPO in these phenomena remains unclear. METHODS: By building the MPO-/- mice, we evaluated relevant inflammatory factors and tissue damage in mice with intestinal Citrobacter rodentium infection and hypoxia. The body weight and excreted microorganisms were monitored. Intestinal tissues were collected 7 days after bacterial infection under hypoxia to undergo haematoxylin-eosin staining and assess the degree of pathological damage. ELISA assays were performed to quantify the serum levels of TNF-α, IFN-γ, IL-6, and IL-1ß inflammatory cytokines. PCR, WB, and IF assays were conducted to determine the expression of chemokines MCP1, MIP2, and KC in the colon and spleen. RESULTS: The C. rodentium infection and hypoxia caused weight loss, intestinal colitis, and splenic inflammatory cells active proliferation in wild-type mice. MPO deficiency alleviated this phenomenon. MPO-/- mice also displayed a significant decline in bacteria clearing ability. The level of TNF-α in the serum and spleen was both lower in MPO-/- hypoxia C. rodentium-infected mice than that in wild-type mice. The chemokines expression levels of MIP2, KC, and MCP1 in the spleen and colon of each bacterial infected group were significantly increased (p < .05), while in hypoxia, the factors in the spleen and colon were decreased (p < .05). MPO deficiency was found to lower the levels of these chemokines compared with wild-type mice. CONCLUSION: MPO plays an important role of the inflammatory responses in infectious enteritis and hypoxia in mice, and the loss of MPO may greatly reduce the body's inflammatory responses to fight diseases.

Hypoxia exacerbates intestinal injury and inflammatory response mediated by myeloperoxidase during Salmonella Typhimurium infection in mice.

BACKGROUND: High-altitude exposure can cause oxidative stress damage in the intestine, which leads to increased intestinal permeability and bacterial translocation, resulting in local and systemic inflammation. Control of infection is critically dependent on the host's ability to kill pathogens with reactive oxygen species (ROS). Myeloperoxidase (MPO) targets ROS in pathogens. This study aimed to investigate the effects of hypoxia on the colonic mucosal barrier and myeloperoxidase (MPO)-mediated innate immune response in the colon. METHODS AND RESULTS: Genetically engineered mice were exposed to a hypobaric oxygen chamber for 3 days and an inflammation model was established using Salmonella Typhimurium infection. We found that hypoxic exposure caused the development of exacerbated bacterial colitis and enhanced bacterial dissemination in MPO-deficient mice. Infection and disease severity were associated with significantly increased Ly6G+ neutrophil and F4/80+ macrophage counts in infected tissues, which is consistent with elevated proinflammatory cytokines and chemoattractant molecules. Hypoxia restrained antioxidant ability and MPO deficiency aggravated the respiratory burst in the colon. CONCLUSION: Hypoxia can damage the colonic mucosa. MPO mediates the innate immune response and regulates the mucosal and systemic inflammatory responses to Salmonella infection during hypoxia.

Hypoxia Attenuates Colonic Innate Immune Response and Inhibits TLR4/NF-κB Signaling Pathway in Lipopolysaccharide-Induced Colonic Epithelial Injury Mice.

High altitude hypoxia can lead to a spectrum of gastrointestinal problems. As the first line of host immune defense, innate immune response in the intestinal mucosa plays a pivotal role in maintaining intestinal homeostasis and protecting against intestinal injury at high altitude. This study aimed to investigate the effect of hypoxia on the colonic mucosal barrier and toll-like receptor 4 (TLR4)-mediated innate immune responses in the colon. The mice were exposed to a hypobaric chamber to simulate a 5,000 m plateau environment for 7 days, and the colonic mucosa changes were recorded. At the same time, the inflammation model was established by lipopolysaccharide (LPS) to explore the effects of hypoxia on the TLR4/nuclear factor kappa B (NF-κB) signaling pathway and its downstream inflammatory factors [tumor necrosis factor-α, interleukin (IL)-1ß, IL-6, and interferon (IFN)-γ] in the colon. We found that hypoxic exposure caused weight loss and structural disturbance of the colonic mucosa in mice. Compared with the control group, the protein levels of TLR4 [fold change (FC) = 0.75 versus FC = 0.23], MyD88 (FC = 0.80 versus FC = 0.30), TIR-domain-containing adaptor protein inducing interferon-ß (TRIF: FC = 0.89 versus FC = 0.38), and NF-κB p65 (FC = 0.75 versus FC = 0.24) in the colon of mice in the hypobaric hypoxia group were significantly decreased. LPS-induced upregulation of the TLR4/NF-κB signaling and its downstream inflammatory factors was inhibited by hypoxia. Specifically, compared with the LPS group, the protein levels of TLR4 (FC = 1.18, FC = 0.86), MyD88 (FC = 1.20, FC = 0.80), TRIF (FC = 1.20, FC = 0.86), and NF-κB p65 (FC = 1.29, FC = 0.62) and the mRNA levels of IL-1ß (FC = 7.38, FC = 5.06), IL-6 (FC = 16.06, FC = 9.22), and IFN-γ (FC = 2.01, FC = 1.16) were reduced in the hypobaric hypoxia plus LPS group. Our findings imply that hypoxia could lead to marked damage of the colonic mucosa and a reduction of TLR4-mediated colonic innate immune responses, potentially reducing host defense responses to colonic pathogens.

Analysis of the gut microbiome in obese native Tibetan children living at different altitudes: A case-control study.

Objective: To explore the relationship between intestinal flora and obesity in Tibetan children at different altitudes. Methods: Using16S rRNA gene sequencing results and blood lipid metabolism indexes to study the characteristics of the intestinal flora present in faeces and changes in blood lipid metabolism in obese children in Tibet who reside at different altitudes and to study correlations between blood lipid metabolism indicators and the intestinal flora composition. Results: The results showed the following. (a) The triglyceride (TG) and low-density lipoprotein cholesterol (LDL-C) levels in the obesity groups were higher than those in the normal-weight groups, and those in the high-altitude obesity groups were lower than those in the low-altitude obesity groups. (b) The 16S rRNA gene sequencing results showed that altitude affected the composition and relative abundance of the gut microbiota. These parameters were basically the same among the low-altitude groups, while they were significantly lower in the high-altitude groups than in the low-altitude groups. (c) Groups that lived at different altitudes and had different body weights had different dominant bacterial genera. Megamonas was closely related to obesity, and its relative abundance in the low-altitude groups was higher than that in the high-altitude groups. Prevotella was associated with altitude, and its relative abundance in the high-altitude groups was higher than that in the low-altitude groups. In addition, Prevotella elicited changes in the abundance of Escherichia-Shigella. The lower prevalence of obesity and incidence of intestinal inflammation in those living at high altitudes were related to the abundance of Prevotella. (d) There were correlations between the gut microbiota composition and lipid metabolism indicators. The abundance of Romboutsia was positively correlated with TG and LDL-C levels but negatively correlated with high-density lipoprotein cholesterol (HDL-C) levels. The abundance of Akkermansia was negatively correlated with LDL-C levels, and the abundance of Blautia was negatively correlated with body mass index (BMI) and LDL-C levels. Conclusions: The intestinal flora diversity varied by body weight and altitude, with lower diversity in those at higher altitudes and with lower body weights. Prevotella likely plays a role in suppressing obesity at high altitudes.

Diacerein: Recent insight into pharmacological activities and molecular pathways.

Diacerein is a symptomatic slow-acting drug in osteoarthritis (SYSADOA) and the active metabolite is rhein. It is a non-steroidal anti-inflammatory drug with unique pharmacological properties as anti-oxidant and anti-apoptosis. Diacerein has recently shown to have a potential role by mediating anti-inflammatory as well as anti-oxidant and anti-apoptosis in kidney injury, diabetes mullites, and a beneficial effect on pain relief. It may have a therapeutic role in cancer, ulcerative colitis, testicular injury and cervical hyperkeratosis. Furthermore, diacerein has a valuable addition in combination therapy as a synergetic agent. This review, the first of its kind, highlights the proposed roles of diacerein in osteoarthritis and discusses recent results supporting its emerging roles with a particular focus on how these new insights may facilitate the rational development of diacerein for targeted therapies in the future.

[New early gastric cancer marker PRDX4 promote the tumorigenesis and progression of gastric cancer via eliminating ROS].

Gastric cancer is the fourth most common cancer in the world and the second leading cause of death in cancer worldwide. In order to reduce the mortality rate of gastric cancer, the problem that needs to be solved at present is to find new specific markers of early gastric cancer and increase the detection rate of early gastric cancer, thus fundamentally solving the problem of high mortality of gastric cancer. Previous studies in our laboratory found that Peroxiredoxin 4 (PRDX4) has the potential for early gastric cancer markers. In this study, the role of PRDX4 in transformed cells was studied by establishing a malignant transformation model and transforming cell overexpression, the experiment proves that PRDX4 is responsible for growth and proliferation by reducing the content of reactive oxygen species (ROS) in transformed cells. In the microenvironment, it promotes the malignant transformation of cells, that is, PRDX4 promotes the development of gastric cancer via eliminating ROS.

[Selection of DNA aptamers to cervical intraepithelial neoplasia by SELEX].

An in vitro synthesized random ssDNA library was subjected to 12 rounds of selection against anti-screening cells and sieving cells by SELEX. Normal and inflammatory cervical exfoliation cells were selected as anti-screening cells, and the cervical exfoliation cells of low-grade squamous intraepithelial lesion (CIN1), high-grade squamous intraepithelial lesion (CIN2, CIN3) and cervical carcinoma were selected as sieving cells during the screening process. Then, the highly specific aptamer CIN-Ap4 was established by the analysis of the specificity, affinity and cell immunofluorescence, which can be used as biomarker for Cervical Intraepithelial Neoplasia. Prime Premier 5.0 was applied to design a random ssDNA library. According to the fixed sequence at both ends of the library, a pair of primers were designed and synthesized. At the same time, the optimal annealing temperature, cycle times and primer concentration ratio of PCR procedure were selected. The results under the optimal condition are shown as follows. In the 50 µL reaction system, the optimum reaction conditions of symmetry PCR are as follows: annealing temperature is 49.5 ℃, number of cycles is 15. The optimal reaction conditions of indirect asymmetric PCR are as follows: the primer concentration ratio is 80:1, and the number of cycles is 35. The experiment proves that the oligonucleotide library is constructed successfully, and the highly specific dsDNA and ssDNA can be obtained under optimal PCR conditions with good repeatability, which establishes the foundation for the further exploration and experimentation.

Glycyrrhizic acid, active component from Glycyrrhizae radix, prevents toxicity of graphene oxide by influencing functions of microRNAs in nematode Caenorhabditis elegans.

We investigated effects of pretreatment with Glycyrrhizae radix (GR) or its specific components on toxicity of graphene oxide (GO) in Caenorhabditis elegans. GR pretreatment prevented GO toxicity on function of both primary and secondary targeted organs. Among active components in GR, the beneficial effects of GR were attributable to presence of glycyrrhizic acid. Glycyrrhizic acid pretreatment suppressed translocation of GO into secondary targeted organs through intestinal barrier. Glycyrrhizic acid pretreatment recovered expression patterns of dysregulated microRNAs (miRNAs) induced by GO, and genes required for oxidative stress control acted as targeted genes for some of these miRNAs. Among these miRNAs, mir-360 mutation enhanced beneficial effects of glycyrrhizic acid. We hypothesize that glycyrrhizic acid may prevent GO toxicity and translocation by influencing functions of miRNAs which upstream regulate functions of their targeted genes. Furthermore, glycyrrhizic acid had potential to extend lifespan, and to suppress accelerated aging process induced by GO. FROM THE CLINICAL EDITOR: Exposure to graphene oxide may pose toxic effects to health, as suggested in animal studies. In this article, the authors showed that the use of glycyrrhizae radix (GR) prevented toxicity of graphene oxide in Caenorhabditis elegans. These results may provide novel strategies in the reducing potential side effects of nanoparticles.

Lactic Acid Bacteria Protects Caenorhabditis elegans from Toxicity of Graphene Oxide by Maintaining Normal Intestinal Permeability under different Genetic Backgrounds.

Lactic acid bacteria (LAB) is safe and useful for food and feed fermentation. We employed Caenorhabditis elegans to investigate the possible beneficial effect of LAB (Lactobacillus bulgaricus) pretreatment against toxicity of graphene oxide (GO) and the underlying mechanisms. LAB prevented GO toxicity on the functions of both primary and secondary targeted organs in wild-type nematodes. LAB blocked translocation of GO into secondary targeted organs through intestinal barrier by maintaining normal intestinal permeability in wild-type nematodes. Moreover, LAB prevented GO damage on the functions of both primary and secondary targeted organs in exposed nematodes with mutations of susceptible genes (sod-2, sod-3, gas-1, and aak-2) to GO toxicity by sustaining normal intestinal permeability. LAB also sustained the normal defecation behavior in both wild-type nematodes and nematodes with mutations of susceptible genes. Therefore, the beneficial role of LAB against GO toxicity under different genetic backgrounds may be due to the combinational effects on intestinal permeability and defecation behavior. Moreover, the beneficial effects of LAB against GO toxicity was dependent on the function of ACS-22, homologous to mammalian FATP4 to mammalian FATP4. Our study provides highlight on establishment of pharmacological strategy to protect intestinal barrier from toxicity of GO.

Role of reactive oxygen species-mediated endoplasmic reticulum stress in contrast-induced renal tubular cell apoptosis.

BACKGROUND: Renal tubular cell apoptosis is a key mechanism of contrast-induced acute kidney injury. It has been reported that endoplasmic reticulum (ER) stress is the underlying mechanism of high osmolar contrast-induced renal tubular cell apoptosis. Whether ER stress is involved in low osmolar contrast-induced renal tubular cell injury remains unclear. In the present study, the roles of ER stress in iopromide-induced (a low osmolar contrast) renal tubular cell apoptosis and the effects of N-acetylcysteine (NAC) on ER stress were investigated. METHODS: NRK-52E cells were exposed to different concentrations of iopromide [50, 100 and 150 mg iodine (I)/ml] for 4 h. In a separate experiment, NRK-52E cells were exposed to iopromide (100 mg I/ml, 4 h) with or without NAC (10 mmol/l). NAC was added 1 h before incubation with iopromide. Apoptosis was determined by Hoechst staining and flow cytometry. The intracellular formation of reactive oxygen species (ROS) was detected by confocal microscopy with fluorescent probe CM-H2DCFDA. The expression of glucose-regulated protein 78 (GRP78) and CAAT/enhancer-binding protein homologous protein (CHOP) was determined by Western blot. RESULTS: Iopromide induced NRK-52E cell apoptosis in a concentration-dependent manner. The intracellular ROS production increased significantly following iopromide exposure in the NRK-52E cells. Significantly increased expressions of GRP78 and CHOP were observed in the NRK-52E cells exposed to iopromide for 4 h; NAC attenuated iopromide-induced NRK-52E cell apoptosis by inhibiting the overproduction of intracellular ROS and subsequently suppressing the overexpression of GRP78 and CHOP. CONCLUSION: ROS-mediated ER stress is involved in contrast-induced renal tubular cell apoptosis.

Transgenerational effects of traffic-related fine particulate matter (PM2.5) on nematode Caenorhabditis elegans.

Numerous studies have demonstrated the toxic effects of fine particle matter less than 2.5 µm (PM2.5) on health of human. However, little information is available on PM2.5 ecotoxicity. We employed Caenorhabditis elegans to investigate the adverse effects of traffic-related PM2.5 on exposed animals and their progeny. Acute exposure to high concentrations of PM2.5 in the range of mg/L caused adverse effects on development, lifespan, reproduction, and locomotion behavior of nematodes. In contrast, prolonged exposure to low concentrations of PM2.5 in the range of µg/L resulted in adverse effects on development, lifespan, reproduction, locomotion behavior, and intestinal development of nematodes. Prolonged exposure to PM2.5 could even cause adverse effects on lifespan, reproduction, locomotion behavior, and intestinal development in progeny of exposed nematodes. PM2.5 toxicity was only partially recovered in progeny of exposed nematodes. For the PM2.5 toxicity on nematodes and their progeny, we hypothesize that it might be the combinational effects of oxidative stress, damage on intestinal barrier, and abnormal defecation behavior. Our data here imply the potential toxic effects of long-term exposure to traffic-related PM2.5 on environmental organisms. Our results further highlight the possible crucial roles of biological barrier and defecation behavior in regulating the PM2.5 toxicity.

In vivo translocation and toxicity of multi-walled carbon nanotubes are regulated by microRNAs.

We employed an in vivo Caenorhabditis elegans assay system to perform SOLiD sequencing analysis to identify the possible microRNA (miRNA) targets of multi-walled carbon nanotubes (MWCNTs). Bioinformatics analysis on targeted genes for the identified dysregulated miRNAs in MWCNT exposed nematodes demonstrates their involvement in many aspects of biological processes. We used loss-of-function mutants for the identified dysregulated miRNAs to perform toxicity assessment by evaluating functions of primary and secondary targeted organs, and found the miRNA mutants with susceptible or resistant property towards MWCNT toxicity. Both the physiological state of the intestine and defecation behavior were involved in the control of the susceptible or resistant property occurrence for specific miRNA mutants towards MWCNT toxicity. This work provides the molecular basis at the miRNA level for future chemical design to reduce the nanotoxicity of MWCNTs and further elucidation of the related toxicological mechanism.

[Effects of selective inhibition of reverse mode of Na(+)/Ca(2+) exchanger on rats with contrast-induced acute kidney injury].

OBJECTIVE: Intracellular Ca(2+) overload is a key factor in contrast-induced renal tubular toxicity. Na(+)/Ca(2+) exchanger (NCX) system is one of main pathways of intracellular Ca(2+) overload. We explore the effects of KB-R7943, an inhibitor of reverse mode of NCX, on contrast-induced acute kidney injury (CI-AKI). METHODS: Rats were divided into control, CI-AKI and pre-treatment groups with KB-R7943 (5, 10 mg/kg). CI-AKI was induced by diatrizoate administration in rats with cholesterol-supplemented diet for 8 weeks. Renal function and hemodynamics were determined at Day 1 post-administration. Renal histopathology was observed under light microscope. Renal tubular apoptosis was examined by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL). Renal endothelin-1 (ET-1) was measured by radioimmunoassay. The oxidative markers of renal malondialdehyde (MDA) and catalase (CAT) were measured. The expression of NCX was evaluated by reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: Levels of serum creatinine (Scr, µmol/L ) in CI-AKI rats ((149 ± 35) µmol/L) were significantly higher than those of normal rats ((55 ± 4) µmol/L, P < 0.01). Renal ET-1, MDA and CAT, resistance index (RI) of renal blood vessels increased significantly in CI-AKI rats. The contrast-induced increases in Scr and RI of renal blood vessels were suppressed significantly and dose-dependently by pretreatment with KB-R7943. Histopathological and TUNEL results showed that contrast-induced severe renal tubular necrosis and apoptosis were significantly and dose-dependently attenuated by KB-R7943. KB-R7943 significantly suppressed the contrast-induced increments of ET-1, MDA and CAT. No significant changes in NCX1 mRNA expression were observed following contrast administration. CONCLUSION: Renal oxidative stress and ET-1 overproduction via the activation of reverse mode of NCX play an important role in the pathogenesis of CI-AKI. And inhibition of reverse mode of NCX expressed in renal tubular epithelial cell has protective effects on CI-AKI.

Na+/Ca2+ exchange inhibitor, KB-R7943, attenuates contrast-induced acute kidney injury.

BACKGROUND: Intracellular Ca2+ overload is considered to be a key factor in contrast-induced acute kidney injury (CI-AKI). The Na+/Ca2+ exchanger (NCX) system is one of the main pathways of intracellular Ca2+ overload. We investigated the effects of KB-R7943, an inhibitor of the reverse mode of NCX, on CI-AKI in a rat model. METHOD: Rats were divided into control group, CI-AKI group and pretreatment groups (with KB-R7943 dose of 5 or 10 mg/kg). CI-AKI was induced by diatrizoate administration in rats with cholesterol-supplemented diet for 8 weeks. Renal function and renal hemodynamics were determined 1 day following contrast medium administration. Renal histopathology was observed by light microscope. Renal tubular apoptosis was examined by TUNEL. Renal endothelin-1 (ET-1) was measured by radioimmunoassay. Renal malondialdehyde (MDA) and catalase (CAT) were measured as oxidative markers. RESULTS: Levels of serum creatinine (Scr), renal ET-1, MDA and CAT, and resistance index (RI) of renal blood vessels increased significantly in CI-AKI rats. The increases in Scr and RI of renal blood vessels induced by diatrizoate were suppressed significantly and dose-dependently by pretreatment with KB-R7943. Histopathological and TUNEL results showed that the contrast medium-induced severe renal tubular necrosis and apoptosis were significantly and dose-dependently attenuated by KB-R7943. KB-R7943 significantly suppressed the increment of renal ET-1 content and MDA and CAT level induced by contrast medium administration. CONCLUSION: Activation of the reverse mode of NCX, followed by ET-1 overproduction and increased oxidative stress, seems to play an important role in the pathogenesis of CI-AKI. The inhibitor of the reverse mode of NCX, KB-R7943, has renoprotective effects on CI-AKI.

Selective inhibition of the reverse mode of Na(+)/Ca(2+) exchanger attenuates contrast-induced cell injury.

BACKGROUND: The precise mechanisms underlying radiocontrast nephropathy (RCN) are not well understood. Intracellular Ca(2+) overload is considered to be a key factor in RCN. The Na(+)/Ca(2+) exchanger (NCX) system is one of the main pathways of intracellular Ca(2+) overload. We investigated whether intracellular Ca(2+) overload via the NCX system was involved in contrast-induced renal tubular cytotoxicity. METHODS: NRK-52E cells were exposed to ioversol (100 mg iodine/ml) for 4 h. KB-R7943 (inhibitor of reverse mode of NCX, 4 × 10(-5), 4 × 10(-6)M) was added 1 h before incubation with ioversol. Cell viability and permeability were determined by 3-(4,5-dimethyldiazol-2-yl)-2,5-diphenyl tetrazolium bromide and lactate dehydrogenase assay. Apoptosis was determined by flow cytometry. Intracellular Ca(2+) concentration ([Ca(2+)](i)] and reactive oxygen species (ROS) were detected by confocal microscopy. The expression of NCX1 mRNA and caspase-3 protein was evaluated by reverse transcription-polymerase chain reaction and Western blot, respectively. RESULTS: Ioversol exposure induced significantly increased lactate dehydrogenase release and decreased 3-(4,5-dimethyldiazol-2-yl)-2,5-diphenyl tetrazolium bromide conversion in NRK-52E cells. Significantly increased apoptosis and caspase-3 protein expression were observed in the NRK-52E cells exposed to ioversol for 4 h. Ioversol treatment induced a significant increase in [Ca(2+)](i) and intracellular ROS. KB-R7943 dose-dependently and significantly suppressed the increase in [Ca(2+)](i), intracellular ROS and caspase-3 overexpression induced by ioversol and attenuated the contrast-induced NRK-52E cell apoptosis. No significant changes in NCX1 mRNA expression were observed following contrast exposure. CONCLUSION: Intracellular Ca(2+) overload via the reverse mode of NCX, followed by ROS overproduction and caspase-3 overexpression played an important role in the contrast-induced renal tubular cytotoxicity. The reverse mode of the NCX inhibitor KB-R7943 attenuated contrast-induced renal tubular cytotoxicity.

Fluvastatin inhibits high glucose-induced nuclear factor kappa B activation in renal tubular epithelial cells.

INTRODUCTION: 3-Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors have been shown to reduce the progression of renal disease independent of cholesterol-lowering effect, but the mechanism of the potential protective effect remains unclear. Here, we investigate the effect of fluvastatin on activation of nuclear factor-kappaB (NF-kappaB) induced by high glucose in rat kidney tubule epithelial cells in vivo and in vitro. METHODS: Streptozotocin (STZ)-induced uninephrectomized diabetic rats were treated daily with fluvastatin (4 mg/kg body weight) by gavage. In 8 weeks the animals were killed, and their urine and blood samples were collected. Blood glucose, blood lipid, the urinary excretion of N-acetyl-beta-D-glucosaminidase (NAG), albumin and creatinine were measured. Immunohistochemical staining of NF-kappaB in the tubulointerstitium was performed. Rat renal tubular epithelial cells (NRK-52E) were cultured under normal glucose, high glucose (HG) and HG with fluvastatin or SB202190 (a specific inhibitor of p38MAPK) or mevalonate. Electrophoretic mobility shift assay (EMSA) was used to detect NF-kappaB activation. Phosphorylation of cellular p38 mitogen-activated protein kinase (p38MAPK) was determined by Western blot analysis. RESULTS: Compared with that in the control group, the expression of NF-kappaB increased in tubulointerstitium of experimental diabetic rats (p<0.01). Fluvastatin significantly inhibited NF-kappaB expression and reduced proteinuria (p<0.01). High glucose stimulated the DNA-binding activity of NF-kappaB and phosphorylation of p38MAPK in cultured NRK-52E cells (p<0.01). This stimulatory effect of high glucose on NF-kappaB was blocked by SB203580. Incubation of cells with fluvastatin significantly inhibited the high glucose-induced NF-kappaB activation in a dose-dependent (10-7 to 10-5 mol/L) manner (p<0.05). Exogenous mevalonate (10-4 mol/L) prevented the effect of fluvastatin on NF-kappaB activation. CONCLUSION: These results suggest that fluvastatin reduces high glucose-induced NF-kappaB activation via the p38MAPK pathway in renal tubular epithelial cells in vivo and in vitro. The effect is at least partly due to blocking the biosynthesis of mevalonate.

Fluvastatin inhibits angiotensin II-induced nuclear factor kappa B activation in renal tubular epithelial cells through the p38 MAPK pathway.

3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors has been shown to reduce the progression of renal disease independent of cholesterol-lowering effect, but the mechanism of potential protective effect remains unclear. Here, we investigate the effect of fluvastatin on activation of nuclear factor-κB (NF-κB) induced by angiotensin II (AngII) in rat kidney tubule epithelial cells (NRK-52E). Electrophoretic mobility shift assays (EMSA) was used to detect NF-κB activation. Phosphorylation of cellular p38 mitogen-activated protein kinase (p38MAPK) was determined by western blot analysis. AngII stimulated the DNA-binding activity of NF-κB and phosphorylation of p38MAPK in cultured NRK-52E cells in a dose-dependent (10(-9)-10(-6) mol/l) manner (P < 0.01). AngII (10(-6) mol/l) induced a rapid (5 min) increase of the p38MAPK phosphorylation. NF-κB DNA-binding activity was increased at as early as 30 min, peaked at 2 h after AngII treatment. This stimulatory effect of AngII on NF-κB was blocked by SB203580 (a specific inhibitor of p38MAPK). Incubation of cells with fluvastatin significantly inhibited the AngII-induced NF-κB activation in a dose-dependent (10(-7)-10(-5) mol/l) manner (P < 0.05). Exogenous mevalonate (10(-4)mol/l) prevented the effect of fluvastatin on NF-κB activation. These results suggest the fluvastatin reduced AngII-induced NF-κB activation via the p38MAPK pathway in NRK-52E cells. The effect is at least partly due to blocking the biosynthesis of mevalonate.

Effect of atorvastatin on dendritic cells of tubulointerstitium in diabetic rats.

Inflammatory reactology has become increasingly important in diabetic kidney disease. In this study, we estabilished STZ-induced diabetic rat model to investigate whether dendritic cells (DCs) mediated tubulointerstitial damages, and whether the effects by DCs were mediated by P-selectin expression and can be inhibited by atorvastatin. The study demonstrated that there was an accumulation of DCs in diabetic rats mediated by P-selectin. It also showed the accumulation of DCs and expression of P-selectin was closely correlated with the degree of renal tubulointerstitial injury. These effects were markedly attenuated by atorvastatin. Thus, DCs play a role in tubulointerstitial damages, atorvasttin can prevent renal tubulointerstitium from damage by inhibiting the P-selectin expression and DCs migration.

The influence of fasudil on the epithelial-mesenchymal transdifferentiation of renal tubular epithelial cells from diabetic rats.

To investigate the influence of fasudil on the epithelial-mesenchymal transdifferentiation of renal tubular epithelial cells from diabetic rats and explore the mechanisms of this effect. Wistar rats were randomly divided into the following three groups: control, diabetes and fasudil-treatment. All rats were sacrificed after three months of feeding with or without fasudil treatment. Pathological changes to the glomeruli and renal interstitium were studied using Periodic acid-Schiff's staining and Masson staining, respectively. Expression of ROCK1, alpha-SMA, E-cadherin and the distribution of beta-catenin in rat renal cortex were revealed by immunohistochemistry. Changes in the MYPT1 phosphorylation profile and alpha-SMA, E-cadherin and membrane beta-catenin expression were revealed by western blot. Changes in the levels of ROCK1, E-cadherin and total beta-catenin mRNA expression were analyzed by real-time PCR. Fasudil treatment notably attenuates renal interstitial fibrosis in diabetic rats. Compared to the control rats, diabetic rats showed elevated phosphorylation of MYPT1, increased expression of ROCK1 and alpha-SMA, decreased expression of E-cadherin and membrane beta-catenin, and increased expression of ROCK1 and total beta-catenin mRNA, decreased expression of E-cadherin mRNA. Fasudil treatment of diabetic rats resulted in attenuated MYPT1 phosphorylation, decreased ROCK1 and alpha-SMA expression, increased E-cadherin and membrane beta-catenin expression, and reduced ROCK1 and total beta-catenin mRNA expression, increased expression of E-cadherin mRNA. In conclusion, fasudil may reduce the epithelial-mesenchymal transdifferentiation and renal interstitial fibrosis in diabetic rats through a mechanism by which ROCK activity is inhibited, which further facilitates the recovery of the cell-cell adhesions among renal tubular epithelial cells and adhesion complex formation.