4-hydroxy-2-nonenal and ferric-nitrilotriacetate

This study was designed to reveal the protective effects of dietary supplementation of curcumin against renal cell tumours and oxidative stress induced by renal carcinogen iron nitrilotriacetate (Fe-NTA) in ddY male mice. The results showed that mice treated with a renal carcinogen, Fe-NTA, a 35% renal cell tumour incidence was noticed, whereas renal cell tumour occurrence was elevated to 80% in Fe-NTA promoted and N-diethylnitrosamine (DEN)-initiated mice as compared with saline- treated mice. No incidence of tumours has been observed in DEN-initiated non-promoted mice. Diet complemented with 0.5% and 1.0% curcumin fed prior to, during and after treatment with Fe-NTA in DEN-initiated animals, tumour incidence was reduced dose-dependently to about 45% and 30% respectively. Immunohistochemical studies also revealed the increased formation of 4-hydroxy-2-nonenal (HNE)-modified protein adducts and 8-hydroxy-2'-deoxyguanosine (8-OHdG) in kidney tissue of mice treated with an intraperitoneal injection of Fe-NTA (6.0 mg Fe/kg body weight.). Furthermore, Fe-NTA treatment of mice also resulted in significant elevation of malondialdehyde (MDA), serum urea, and creatinine and decreases renal glutathione. However, the changes in most of these parameters were attenuated dose-dependently by prophylactic treatment of animals with 0.5% and 1% curcumin diet, this may be due to its antioxidative impact of curcumin. These results suggest that intake of curcumin is beneficial for the prevention of renal cell tumours and oxidative stress damage mediated by renal carcinogen, Fe-NTA.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Aldehydes; Animals; Anticarcinogenic Agents; Antineoplastic Agents, Phytogenic; Antioxidants; Blood Urea Nitrogen; Carcinogens; Carcinoma, Renal Cell; Creatinine; Curcumin; Diet; Diethylnitrosamine; Dose-Response Relationship, Drug; Ferric Compounds; Kidney Neoplasms; Male; Mice; Nitrilotriacetic Acid; Oxidative Stress

Ferric nitrilotriacetate (Fe-NTA) is a potent nephrotoxicant and a renal carcinogen that induces its effect by causing oxidative stress. The present study was undertaken to explore protective effect of silymarin, a flavonolignan from milk thistle (Silybum marianum), against Fe-NTA mediated renal oxidative stress, inflammation and tumor promotion response along with elucidation of the implicated mechanism(s). Administration of Fe-NTA (10 mg/kg bd wt, i.p.) to Swiss albino mice induced marked oxidative stress in kidney, evident from augmentation in renal metallothionein (MT) expression, depletion of glutathione content and activities of antioxidant and phase II metabolizing enzymes, and enhancement in production of aldehyde products such as 4-hydroxy-2-nonenal. Fe-NTA also significantly activated nuclear factor kappa B (NFkappaB) and upregulated the expression of downstream genes: cyclooxygenase 2 and inducible nitric oxide synthase and enhancing the production of proinflammatory cytokines: tumor necrosis factor alpha (TNF-alpha) and interleukin-6 (IL-6). However, feeding of 0.5% and 1% silymarin diet conferred a significant protection against Fe-NTA induced oxidative stress and inflammation. It further augmented MT expression, restored the antioxidant armory, ameliorated NFkappaB activation and decreased the expression of proinflammatory mediators. Silymarin also suppressed Fe-NTA induced hyperproliferation in kidney, ameliorating renal ornithine decarboxylase activity and DNA synthesis. From these results, it could be concluded that silymarin markedly protects against chemically induced renal cancer and acts plausibly by virtue of its antioxidant, anti-inflammatory and antiproliferative activities.

Topics: Aldehydes; Animals; Antioxidants; Cyclooxygenase 2; Cytokines; Dietary Supplements; DNA, Neoplasm; Female; Ferric Compounds; Inflammation; Inflammation Mediators; Kidney; Kidney Neoplasms; Lipid Peroxidation; Metabolic Detoxication, Phase II; Metallothionein; Mice; NF-kappa B; Nitric Oxide Synthase Type II; Nitrilotriacetic Acid; Ornithine Decarboxylase; Protective Agents; Silymarin; Treatment Outcome

Curcumin (diferuloylmethane), a biologically active ingredient derived from rhizome of the plant Curcuma longa, has potent anticancer properties as demonstrated in a plethora of human cancer cell lines/animal carcinogenesis model and also acts as a biological response modifier in various disorders. We have reported previously that dietary supplementation of curcumin suppresses renal ornithine decarboxylase (Okazaki et al. Biochim Biophys Acta 1740:357-366, 2005) and enhances activities of antioxidant and phase II metabolizing enzymes in mice (Iqbal et al. Pharmacol Toxicol 92:33-38, 2003) and also inhibits Fe-NTA-induced oxidative injury of lipids and DNA in vitro (Iqbal et al. Teratog Carcinog Mutagen 1:151-160, 2003). This study was designed to examine whether curcumin possess the potential to suppress the oxidative damage caused by kidney-specific carcinogen, Fe-NTA, in animals. In accord with previous report, at 1 h after Fe-NTA treatment (9.0 mg Fe/kg body weight intraperitoneally), a substantial increased formation of 4-hydroxy-2-nonenal (HNE)-modified protein adducts in renal proximal tubules of animals was observed. Likewise, the levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG) and protein reactive carbonyl, an indicator of protein oxidation, were also increased at 1 h after Fe-NTA treatment in the kidneys of animals. The prophylactic feeding of animals with 1.0% curcumin in diet for 4 weeks completely abolished the formation of (i) HNE-modified protein adducts, (ii) 8-OHdG, and (iii) protein reactive carbonyl in the kidneys of Fe-NTA-treated animals. Taken together, our results suggest that curcumin may afford substantial protection against oxidative damage caused by Fe-NTA, and these protective effects may be mediated via its antioxidant properties. These properties of curcumin strongly suggest that it could be used as a cancer chemopreventive agent.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Aldehydes; Animals; Antioxidants; Carcinogens; Chemoprevention; Curcumin; Deoxyguanosine; Ferric Compounds; Kidney; Kidney Tubules, Proximal; Male; Mice; Neoplasms; Nitrilotriacetic Acid; Oxidative Stress; Proteins

Iron is known to be involved in neuronal diseases such as neurodegenerative diseases, brain ischemia and epilepsy. However, it is unclear if a high level of peripheral iron induces these pathological conditions. Since ferric nitrilotriacetate (Fe-NTA), a low molecule iron chelate, causes kidney carcinoma and diabetes in animals due to its strong and unique oxidative stress, it is also considered to cause pathological conditions in the brain. Therefore, we studied brain changes after intraperitoneal (i.p.) injection of Fe-NTA. We investigated iron distribution in the brain and evaluated heme oxygenase (HO)-1 mRNA, IL-6 mRNA and 4-hydroxy-2-nonenal (4-HNE) quantitatively. In addition, changes in muscarinic acetylcholine receptor mRNAs were measured. It was found that iron was localized in the cortex and the hypothalamus, but not in other areas of the brain. HO-1 was induced in both the cortex and hypothalamus, and the levels of IL-6 and 4-HNE were raised in the hypothalamus, but not in the cortex. In the cortex, expression in M1 and M2 mAChRs were suppressed. In conclusion, iron reached the brain parenchyma after i.p. injection of Fe-NTA, and Fe-NTA caused oxidative reactions and suppression of mAChRs in the brain.

Topics: Aldehydes; Animals; Brain; Cerebral Cortex; Ferric Compounds; Heme Oxygenase (Decyclizing); Histocytochemistry; Hypothalamus; Immunoblotting; Injections, Intraperitoneal; Interleukin-6; Iron; Iron Chelating Agents; Male; Nitrilotriacetic Acid; Oxidative Stress; Polymerase Chain Reaction; Rats; Rats, Sprague-Dawley

Iron is a relevant risk factor for colorectal cancer due to its genotoxic properties. Here we hypothesised that iron-overload causes other toxic effects, which contribute to carcinogenesis. For this, we investigated formation of reactive oxygen species (ROS), DNA repair, cell growth and glutathione (GSH) in human colon tumor cells (HT29 clone 19A) treated with ferric nitrilotriacetate (Fe-NTA, 0-2000 microM). Intracellular formation of ROS was analysed with the peroxide-labile fluorescent dye carboxy-dichlorodihydrofluorescine-diacetate. DNA repair, reflected as the persistency of DNA damage induced by selected genotoxins, was determined with the Comet assay. Cell growth and GSH were measured by fluorimetrical analysis. Key findings were that ROS formation increased with time (1000 microM Fe-NTA, p < 0.001). DNA damage was largely repaired after 120 min, but was not affected by 10 microM Fe-NTA. In contrast, 10 microM Fe-NTA significantly increased DNA damage induced by 4-hydroxynonenal. Doses of 25 microM Fe-NTA increased cell growth (p < 0.05), whereas high concentrations (2000 microM) resulted in growth arrest (p < 0.05), that was accompanied by increased GSH levels (p < 0.01). In conclusion, high concentrations of Fe-NTA caused cellular effects, which reflect a stress response, and resulted in formation of ROS. Carcinogenic risks from ferric iron could be derived also from lower concentrations, which enhance tumor cell growth and cause progenotoxic effects.

Topics: Aldehydes; Cell Proliferation; Colonic Neoplasms; DNA Damage; Ferric Compounds; Glutathione; HT29 Cells; Humans; Nitrilotriacetic Acid; Reactive Oxygen Species

4-Hydroxy-2-nonenal (HNE), a major lipid peroxidation product, reacts with histidine, lysine or cysteine residues of proteins to form hemiacetal Michael adducts and thus interferes with the functions of the proteins. Here we undertook to identify HNE-modified proteins in the target organ of a ferric nitrilotriacetate (Fe-NTA)-induced renal carcinogenesis model with histidine-specific HNEJ-2 antibody. Immunoaffinity column separation and sequencing identified one of the major modified proteins as actin. To further explore the characteristics of actin as an HNE acceptor, we produced four novel monoclonal antibodies against HNE-modified keyhole limpet hemocyanin. All these antibodies (HNEJ-1, 3-5) recognized histidine adducts, but were different from HNEJ-2 in recognizing lysine and cysteine adducts to some extent. Actin, albumin, glyceraldehyde 3-phosphate dehydrogenase (GAPDH), metallothionein and superoxide dismutase were treated in vitro with HNE and evaluated with these antibodies. The results revealed that actin was most sensitive to HNE modification and metallothionein most resistant. Furthermore, the residue-specificity of GAPDH was in accord with that shown by our recent mass spectrometry data. Immunohistochemistry with the antibodies revealed cytoplasmic staining with or without nuclear staining in the renal proximal tubules after Fe-NTA administration. The results suggest that actin is a major target protein for HNE modification in vivo, and that our monoclonal antibodies are useful for evaluating the HNE adducts produced.

Topics: Actins; Albumins; Aldehydes; Animals; Antibodies, Monoclonal; Blotting, Western; Cysteine; Ferric Compounds; Glyceraldehyde-3-Phosphate Dehydrogenases; Hemocyanins; Histidine; Kidney; Kidney Neoplasms; Lysine; Male; Metallothionein; Nitrilotriacetic Acid; Rats; Rats, Wistar; Specific Pathogen-Free Organisms; Superoxide Dismutase

In experiments using the renal carcinogen ferric nitrilotriacetate (Fe-NTA) in male ddY mice, primary pulmonary cancers were also induced in bronchiolar and alveolar tissues. 4-Hydroxy-2-nonenal (4-HNE) and 8-hydroxy-2'-deoxyguanosine (8-OHdG), products of oxidative processes, increased in bronchiolar and alveolar cells after administration of Fe-NTA. These substances disappeared after oral administration of propolis or artepillin C, as shown histochemically, and correlated with an anticancer prophylactic effect of propolis and artepillin C. From our investigation, lipid peroxidation seems to play an important role in pulmonary carcinogenesis. Malignant progression from adenoma of bronchiolar or alveolar origin to malignant tumors has been proposed to involve a stepwise transformation. In our study, adenomas developed into adenocarcinomas and large cell carcinomas after treatment with Fe-NTA. In contrast, after oral administration of propolis or artepillin C, adenomas did not progress to carcinomas. Instead of developing into large cell cancers, as induced by Fe-NTA in control mice, adenomas showed remarkable proliferation of macrophages and local anti-oxidant activity after treatment with either propolis or artepillin C. Propolis and artepillin C therefore appear to inhibit lipid peroxidation and the development of pulmonary cancers.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Aldehydes; Animals; Antineoplastic Agents; Deoxyguanosine; Ferric Compounds; Immunohistochemistry; Lipid Peroxidation; Lung Neoplasms; Male; Mice; Nitrilotriacetic Acid; Nuclear Proteins; Phenylpropionates; Proliferating Cell Nuclear Antigen; Propolis; Thyroid Nuclear Factor 1; Transcription Factors

The protective effect of Brazilian propolis and its extract Artepillin C against ferric nitrilotriacetate (Fe-NTA)-induced renal lipid peroxidation and carcinogenesis was studied in male ddY mice. Fe-NTA-induced renal lipid peroxidation leads to a high incidence of renal cell carcinoma (RCC) in mice. Administration of propolis by gastric intubation 2 h before or Artepillin C at either the same time, 2 h, or 5 h before the intraperitoneal injection of Fe-NTA (7 mg Fe/kg) effectively inhibited renal lipid peroxidation. This was evaluated from the measurement of renal thiobarbituric acid-reactive substances (TBARS) or histochemical findings of 4-hydroxy-2-nonenal (4-HNE)-modified proteins and 8-hydroxy-2'-deoxyguanosine (8-OHdG). Repeated injection of Fe-NTA (10 mg Fe/kg per day, twice a week for a total of 16 times in 8 weeks) caused subacute nephrotoxicity as revealed by necrosis and pleomorphic large nuclear cells in the renal proximal tubules, and gave rise to RCC 12 months later. A protective effect from carcinogenicity was observed in mice given propolis or Artepillin C. Furthermore, the mice given Fe-NTA only developed multiple cysts composed of precancerous lesions with multilayered and proliferating large atypical cells. Mice treated with propolis and Artepillin C also had cysts, but these were dilated and composed of flat cells. These results suggest that propolis and Artepillin C prevent oxidative renal damage and the carcinogenesis induced by Fe-NTA in mice.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Aldehydes; Animals; Antineoplastic Agents; Carcinoma, Renal Cell; Deoxyguanosine; Disease Models, Animal; Electron Spin Resonance Spectroscopy; Female; Ferric Compounds; Fluorescent Antibody Technique, Indirect; Kidney; Kidney Neoplasms; Lipid Peroxidation; Male; Mice; Mutagens; Nitrilotriacetic Acid; Phenylpropionates; Propolis; Thiobarbituric Acid Reactive Substances

In this study, we show that the toxicity of ferric nitrilotriacetate (Fe-NTA) can be correlated with the tissue accumulation of 4-hydroxy-2-nonenal (HNE)-modified protein adducts. It is observed that the toxic manifestations of Fe-NTA gradually increase with the increasing age of animals. A dose of Fe-NTA which produces almost 100% mortality in aged rats causes 70% mortality in adults, 30% in pups, 20% in litters, and less than 10% in neonates. The age-dependent increase in its toxicity is also evident from the data of renal microsomal lipid peroxidation and hydrogen peroxide generation. No significant difference in the generation of H2O2 and induction of renal microsomal lipid peroxidation between saline- and Fe-NTA-treated neonates, litters, and pups could be observed. However, in adult rats, a significant increase in both of the parameters was observed which was even greater in aged rats. On the contrary, renal glutathione levels in these animals show an inverse relationship with the oxidant generation. In neonates, litters, and pups the maximum decrease of glutathione was up to 22%, whereas in adult and aged rats, the depletion was more than 60% of their respective saline-treated controls. Parallel to this data, blood urea nitrogen and creatinine, the indicators of renal damage, show a significant increase in Fe-NTA-treated adult and aged rats only, whereas no significant alterations were observed in other groups. Similarly, the magnitude of ODC induction and [3H]thymidine incorporation was much higher in aged and adult rats in comparison to other groups of animals after Fe-NTA treatment. Additionally, the immunohistochemical localization studies show a significant increase in HNE-modified protein adducts in kidney of adult and aged rats, whereas no significant staining was observed in other groups. A similar increase in the level of protein carbonyls has also been observed with the increasing age of rats. These data suggest that the toxicity of Fe-NTA increases with the increasing age of rats and correlates with the accumulation of HNE-modified protein adducts. It may also be speculated that Fe-NTA-mediated renal toxicity leading to carcinogenesis may be related to the tissue accumulation of HNE-modified protein adducts. However, further studies are needed to establish a definite role of HNE-modified proteins in Fe-NTA-mediated carcinogenesis.

Topics: Aging; Aldehydes; Animals; Blood Urea Nitrogen; Carcinogens; Cell Division; Creatinine; Ferric Compounds; Ketones; Kidney; Lipid Peroxidation; Male; Microsomes; Neoplasms; Nitrilotriacetic Acid; Ornithine Decarboxylase; Oxidative Stress; Proteins; Rats; Rats, Wistar; Survival Analysis

Intraperitoneal (IP) injection of ferric nitrilotriacetate (Fe-NTA) to rats and mice results in iron-induced free radical injury and cancer in kidneys. We sought to clarify the exact localization of acute oxidative damage in Fe-NTA-induced nephrotoxicity by performing immunogold light and electron microscopic (EM) techniques using an antibody against 4-hydroxy-2-nonenal (HNE)-modified proteins. Biochemical assays were done to provide complementary quantitative data. Renal accumulation of lipid peroxidation-derived aldehydes, such as malondialdehyde (MDA) and 4-hydroxy-2-alkenals (4-HDA), increased in parallel with protein carbonyl content, an indicator of protein oxidation, 30 min after administration of Fe-NTA. Immunogold light microscopy showed that HNE-modified proteins increased at 30 min with positivity localized to proximal tubular cells. Immunogold EM demonstrated that HNE-modified proteins were mainly in the mitochondria and nuclei of the proximal tubular epithelium. The intensity of labeling at both the light and EM levels increased together with levels of biochemically measured lipid peroxidation products and protein carbonyl content. Our data suggest that the mechanism of acute nephrotoxicity of Fe-NTA involves mitochondrial and nuclear oxidative damage, findings that may help to define the mechanisms of iron-induced cell injury.

Topics: Aldehydes; Animals; Cell Nucleus; Ferric Compounds; Free Radicals; Kidney; Kidney Tubules, Proximal; Lipid Peroxidation; Male; Malondialdehyde; Mice; Microscopy, Immunoelectron; Mitochondria; Nitrilotriacetic Acid; Oxidation-Reduction; Proteins; Rats; Rats, Wistar

Oxidative stress is associated with important pathophysiological events in a variety of diseases. It has been postulated that free radicals and lipid peroxidation products generated during the process may be responsible for these effects because of their ability to damage cellular components such as membranes, proteins, and DNA. In the present study, we provide evidence that oxidative stress causes a transient impairment of intracellular proteolysis via covalent binding of 4-hydroxy-2-nonenal (HNE), a major end product of lipid peroxidation, to proteasomes. A single intraperitoneal treatment with the renal carcinogen, ferric nitrilotriacetate, caused oxidative stress, as monitored by accumulation of lipid peroxidation products and 8-hydroxy-2'-deoxyguanosine, in the kidney of mice. In addition, transient accumulation of HNE-modified proteins in the kidney was also found by competitive enzyme-linked immunosorbent assay and immunohistochemical analyses. This and the observation that the HNE-modified proteins were significantly ubiquitinated suggested a crucial role of proteasomes in the metabolism of HNE-modified proteins. In vitro incubation of the kidney homogenates with HNE indeed resulted in a transient accumulation of HNE-modified proteins, whereas the proteasome inhibitor significantly suppressed the time-dependent elimination of HNE-modified proteins. We found that, among three proteolytic activities (trypsin, chymotrypsin, and peptidylglutamyl peptide hydrolase activities) of proteasomes, both trypsin and peptidylglutamyl peptide hydrolase activities in the kidney were transiently diminished in accordance with the accumulation of HNE-modified proteins during oxidative stress. The loss of proteasome activities was partially ascribed to the direct attachment of HNE to the protein, based on the detection of HNE-proteasome conjugates by an immunoprecipitation technique. These results suggest that HNE may contribute to the enhanced accumulation of oxidatively modified proteins via an impairment of ubiquitin/proteasome-dependent intracellular proteolysis.

Topics: Adenosine Triphosphate; Aldehydes; Animals; Cysteine Endopeptidases; Ferric Compounds; Male; Mice; Multienzyme Complexes; Nitrilotriacetic Acid; Oxidative Stress; Proteasome Endopeptidase Complex; Proteins

An iron chelate, ferric nitrilotriacetate (Fe-NTA), induces renal proximal tubular necrosis associated with lipid peroxidation and oxidative DNA damage that finally leads to a high incidence of renal cell carcinoma in rodents. In the present study, we investigated what kinds of C(2-12) saturated and unsaturated aldehydes and C(7-12) acyloins, metabolites of saturated aldehydes, are produced in the kidney and liver within 24 h after single i.p. administration of 15 mg Fe/kg of Fe-NTA, or after repeated (1 or 3 wk) i.p. administration of 5-10 mg Fe/kg of Fe-NTA. Amounts of twenty one aldehydes and five acyloins were determined by capillary column gas chromatography-negative-ion chemical ionization mass spectrometry with ammonia as reagent gas. Most of the aldehydes and all the acyloins measured revealed a significant dose-dependent increase 1 to 3 h after single administration in the kidney, among which 4-hydroxy-2-nonenal (HNE) showed the highest increase (27.3-fold) and malondialdehyde (MDA) was the most abundant aldehyde (2.40 nmol/100 mg wet tissue). In the liver, however, the increase in aldehydes and acyloins was less prominent. After repeated administration of Fe-NTA, only 9 aldehydes (ethanal; furfural; trans,trans-2,4-heptadienal; nonanal; trans-2,cis-6-nonadienal; HNE; decanal; trans-4,cis-4-decenal; MDA) and 4 acyloins (3-hydroxyheptan-2-one; 3-hydroxyoctan-2-one; 3-hydroxynonan-2-one; 3-hydroxydodecan-2-one) showed a significant increase. Immunohistochemistry further demonstrated an increased amount of HNE-modified and MDA-modified proteins in the renal proximal tubules after repeated Fe-NTA administration. Some of the aldehydes measured such as HNE and MDA are reportedly cytotoxic, genotoxic and mutagenic. Accumulation of these aldehydes may play a role in this renal carcinogenesis model.

Topics: Aldehydes; Animals; Carcinogens; Carcinoma, Renal Cell; Chromatography, Gas; Fatty Alcohols; Ferric Compounds; Immunohistochemistry; Kidney; Kidney Neoplasms; Kinetics; Liver; Male; Malondialdehyde; Nitrilotriacetic Acid; Rats; Rats, Wistar

Ferric nitrilotriacetate (Fe-NTA) is a renal toxicant and carcinogen in rats and mice. We found that its administration results in formation of 4-hydroxy-2-nonenal (HNE) in the renal proximal tubule cells of rats, and 8-hydroxydeoxyguanosine (8-OHdG) adducts in their DNA, suggesting a role for oxidative stress. Since 2-mercaptoethane sulfonate (MESNA) and N-acetylcysteine (NAC), administered orally, have been shown to increase the kidney levels of free thiol groups, their influence on the renal toxicity and carcinogenicity induced by Fe-NTA was examined in the present study. Male Wistar rats were intraperitoneally injected with Fe-NTA (12 mg Fe/kg), and MESNA (100 mg/kg) or NAC (200 mg/kg) was given orally 1 h before and 1 h after this treatment. The animals were killed for tissue analyses 3 h after the Fe-NTA exposure. In accord with our previous reports, HNE-modified protein was detected in the proximal tubules of Fe-NTA-treated rats by means of immunohistochemistry. Likewise, levels of 8-OHdG in the renal nuclear DNA, lipid peroxides as thiobarbituric acid-reactive substances in the kidneys, and blood urea nitrogen and creatinine in the serum were significantly increased by the Fe-NTA treatment. All of these changes were completely inhibited by oral administration of MESNA or NAC. These results suggest that both of these compounds can prevent the oxidative stress induced by Fe-NTA.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Acetylcysteine; Aldehydes; Animals; Antioxidants; Carcinogens; Deoxyguanosine; DNA; DNA Damage; Ferric Compounds; Kidney; Kidney Diseases; Kidney Tubules, Proximal; Lipid Peroxidation; Male; Mesna; Nitrilotriacetic Acid; Oxidative Stress; Rats; Rats, Wistar; Thiobarbituric Acid Reactive Substances

An iron chelate, ferric nitrilotriacetate (Fe-NTA), induces proximal tubular necrosis, a consequence of lipid peroxidation, that finally leads to a high incidence of renal adenocarcinoma in rodents. Lipid peroxidation as monitored by formation of thiobarbituric acid-reactive substances and free 4-hydroxy-2-nonenal (HNE) was observed in the kidney homogenates of rats treated with Fe-NTA. Based on the fact that HNE is capable of reacting with cellular proteins, we attempted to detect the localization of HNE-modified proteins in rat kidney tissues with an immunohistochemical procedure. By means of an immunohistochemical technique using polyclonal antibody against the HNE-modified proteins, it was shown that HNE-modified proteins are formed in the target cells of this carcinogenesis model. HNE-modified proteins were detected in the renal proximal tubules 1 hr after i.p. administration of Fe-NTA (15 mg of iron per kg). Intense positivity was found in the cells with degeneration. After 6 hr, the level of HNE-protein conjugates decreased due to the subsequent necrosis. The intensity of the immunochemical reaction with HNE-modified proteins increased in parallel with an increase in the amounts of thiobartituric acid-reactive substances and free HNE that were found. Furthermore, histochemical detection of aldehydes by cold Schiff's reagent demonstrated that location of aldehydes was identical to that of the HNE-modified proteins determined by immunohistochemical procedures. It would thus appear that the production of HNE, a genotoxic and mutagenic aldehyde, and its reaction with proteins may play a role in Fe-NTA-induced renal carcinogenesis.

Topics: Aldehydes; Animals; Carcinogens; Dose-Response Relationship, Drug; Ferric Compounds; Histocytochemistry; Immunohistochemistry; Kidney Cortex; Kidney Tubules, Proximal; Male; Nitrilotriacetic Acid; Proteins; Rats; Rats, Wistar; Thiobarbituric Acid Reactive Substances; Time Factors