ascorbic-acid and nickel-chloride

Nickel is an abundant carcinogenic and nephrotoxic metal whose activity leads to renal impairment. Previous studies have shown a protective effect of simultaneous vitamin C administration on acute and chronic nickel toxicity. However, very little research relating to the effect of vitamin C pretreatment in preventing nickel-induced acute nephrotoxicity is available. Therefore, the present study aimed to determine the efficiency of vitamin C (VC) pretreatment in preventing acute renal toxicity of nickel. Mice were pretreated orally with vitamin C (16.6 mg kg-1 body weight, b.w.) for seven consecutive days, prior to intraperitoneal (i.p.) administration of nickel chloride at different doses (3, 5, and 10 mg Ni kg-1 b.w.) for an exposure period of 24 hours. Thereafter, animals were killed and kidney tissue and blood samples were taken for histological examination and biochemical marker analyses. Vitamin C pretreatment alone did not alter the levels of serum kidney markers (creatinine, urea, and uric acid). However, treatment with Ni alone showed a significant increase in the levels of serum creatinine, urea, and uric acid with marked necrotic epithelial cells and infiltration by inflammatory cells in kidney sections as compared to the control group. Pretreatment with vitamin C and treatment with Ni at all doses tested for 24 hours showed a significant decrease in the levels of serum creatinine, urea, and uric acid, as well as an improvement in histological changes compared to those previously seen in the group treated with Ni alone. It is concluded that vitamin C pretreatment effectively improved renal function and tissue damage caused by nickel.

Topics: Acute Kidney Injury; Animals; Antioxidants; Ascorbic Acid; Chemically-Induced Disorders; Kidney Function Tests; Male; Mice; Nickel; Protective Agents

Abnormal expression of histone demethylase Jumonji domain-containing protein 1A (JMJD1A) is associated with many kinds of cancers. JMJD1A is also a hypoxic response gene and its expression is regulated by hypoxia-inducible factor-1α (HIF-1α). In this study, we determined the role of JMJD1A in development and hypoxia pathway. We also measured the expression of JMJD1A and two hypoxia factors glucose transporter 1 (GLUT1) and vascular endothelial growth factor (VEGF) in 786-0 and HEK293 cells treated with different concentrations of NiCl(2) (2.5-100 μM) for 24 h, and found that JMJD1A mRNA and protein were up-regulated with increased concentrations of NiCl(2). We then observed that ascorbate could retard the up-regulated effect of NiCl(2)-induced JMJD1A expression in a dose-dependent manner through decreasing the stability of HIF-1α protein. Immunohistochemical analysis further demonstrated ascorbate antagonized Ni(2+)-induced up-regulation of JMJD1A expression in 786-0, HEK293, and OS-RC-2 cells. These findings suggest that both Ni(2+) and ascorbate can regulate the expression of histone demethylase JMJD1A, which is important for cancer development or inhibition.

Topics: Animals; Antioxidants; Ascorbic Acid; Blotting, Western; Cell Line, Tumor; Dose-Response Relationship, Drug; Drug Antagonism; Gene Expression Regulation, Neoplastic; HEK293 Cells; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Immunohistochemistry; Jumonji Domain-Containing Histone Demethylases; Kidney; Kidney Neoplasms; Male; Mice; Mice, Inbred BALB C; Nickel; Reverse Transcriptase Polymerase Chain Reaction

Using the comet assay, we showed that nickel chloride at 250-1000 microM induced DNA damage in human lymphocytes, measured as the change in comet tail moment, which increased with nickel concentration up to 500 microM and then decreased. Observed increase might follow from the induction of strand breaks or/and alkali-labile sites (ALS) by nickel, whereas decrease from its induction of DNA-DNA and/or DNA-protein cross-links. Proteinase K caused an increase in the tail moment, suggesting that nickel chloride at 1000 microM might cross-link DNA with nuclear proteins. Lymphocytes exposed to NiCl(2) and treated with enzymes recognizing oxidized and alkylated bases: endonuclease III (Endo III), formamidopyrimidine-DNA glycosylase (Fpg) and 3-methyladenine-DNA glycosylase II (AlkA), displayed greater extent of DNA damage than those not treated with these enzymes, indicating the induction of oxidized and alkylated bases by nickel. The incubation of lymphocytes with spin traps, 5,5-dimethyl-pyrroline N-oxide (DMPO) and PBN decreased the extent of DNA damage, which might follow from the production of free radicals by nickel. The pre-treatment with Vitamin C at 10 microM and Vitamin E at 25 microM decreased the tail moment of the cells exposed to NiCl(2) at the concentrations of the metal causing strand breaks or/and ALS. The results obtained suggest that free radicals may be involved in the formation of strand breaks or/and ALS in DNA as well as DNA-protein cross-links induced by NiCl(2). Nickel chloride can also alkylate DNA bases. Our results support thesis on multiple, free radicals-based genotoxicity pathways of nickel.

Topics: Adult; Antioxidants; Ascorbic Acid; Cell Survival; Comet Assay; Cross-Linking Reagents; DNA; DNA Damage; DNA Repair; Free Radical Scavengers; Free Radicals; Humans; Hydrogen Peroxide; Lymphocytes; Male; Nickel; Oxidants; Oxidation-Reduction; Vitamin E

This study was undertaken to examine the effects of nickel (Ni) on human platelet function. In a (concentration-dependent manner, Ni significantly inhibited the function of platelet aggregation induced by collagen. The phenomenon of lipid peroxidation was involved as Ni significantly increased malondialdehyde (MDA) levels with reduction in platelet reduced glutathione (GSH) and alpha-tocopherol content. Further, platelet thromboxane B2, formation was markedly inhibited and the levels of cyclic AMP were significantly elevated by Ni. Treatment with ascorbic acid (Vit C) significantly lowered the levels of MDA and increased the content of alpha-tocopherol and reduced GSH. Vit C also significantly increased platelet aggregation and thromboxane B2 when coincubated with Ni. Data show that Ni is toxic as evidenced by lipid peroxidative damage and inhibition of human platelet aggregation, but that ascorbic acid provides protection, at least partially, against this metal.

Topics: Ascorbic Acid; Blood Platelets; Cyclic AMP; Glutathione; Humans; In Vitro Techniques; Lipid Peroxidation; Nickel; Oxidative Stress; Platelet Aggregation; Thromboxane B2; Vitamin E

Chromium and nickel compounds cause irritancy but can also induce allergic contact dermatitis. The aims of this study were to characterize the direct cytotoxic effects of Cr(VI), Cr(III) and Ni(II) salts on keratinocytes, and to investigate pharmacological strategies to protect cells against Cr(VI)-induced cytotoxicity. Normal human keratinocytes and the HaCaT keratinocyte cell line were used. Cell viability was assessed by neutral red dye uptake, the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) eluted stain assay and measurement of lactate dehydrogenase (LDH) activity in the medium. The assays varied slightly in their sensitivities (neutral red > MTT > LDH) although all three gave similar results. In both cell types, the relative order of cytotoxicity of the salts was Cr(VI) >> Ni(II) > Cr(III). There were no major differences between chromium salts of a common valency. Normal human keratinocytes showed a much greater variability in their response to Cr(VI) and Ni(II) salts than HaCaT cells and were generally more resistant to Cr(VI)- and Ni(II)-induced cytotoxicity. Several drugs were screened for their potential to protect both cell types against the cytotoxic effects of Cr(VI), specifically the reducing agents ascorbic acid, cysteine and glutathione, and the Cr(VI) cellular uptake inhibitors 4,4'-diisothiocyanato-2,2'-stilbenedisulphonic acid (DIDS) and 4-acetamido-4'-isothiocyanato-2,2'-stilbenedisulphonic acid (SITS). All five drugs provided concentration-dependent protection against Cr(VI)-induced cytotoxicity but only ascorbic acid offered complete protection. Several of these pharmacological approaches to the prevention of Cr(VI) cytotoxicity confirm previous clinical studies on the inactivation of Cr(VI), while the clinical potential of others has yet to be investigated.

Topics: Ascorbic Acid; Cell Culture Techniques; Cell Death; Cell Line, Transformed; Cell Survival; Chromium; Dose-Response Relationship, Drug; Humans; Keratinocytes; L-Lactate Dehydrogenase; Neutral Red; Nickel; Tetrazolium Salts; Thiazoles

Various small oxidation products (e.g. 8-hydroxydeoxyguanosine) can be induced in DNA by nickel compounds. In this study, the 32P-postlabeling assay was applied to determine whether Ni(II) compounds are able to induce bulky DNA-adduct formation in vitro and in vivo. In vitro studies detected two major and several minor adducts in DNA incubated with NiCl2 and H2O2 at 37 degrees C for 1 h. Formation of the two major adducts increased with incubation time (0-24 h) and NiCl2 concentration (0-800 microM). Adduct levels were greatly reduced by hydroxyl free-radical scavengers, i.e. 0.4 M sodium formate or 0.05 M p-nitrosodimethylaniline, and by a singlet oxygen scavenger, 0.05 M sodium azide. The in vitro effects of NiCl2 on DNA were significantly enhanced by (1) addition of 3 mM ascorbic acid, (2) replacement of H2O with D2O in the reaction, and (3) prior denaturation of DNA. Adduct formation presumably involved a Fenton-type reaction, in which DNA crosslinks may arise by reaction with hydroxyl free radicals and singlet oxygen. For in vivo studies, male 6-8 wk old B6C3F1 mice were used. In untreated mice, several I-compounds (putative indigenous DNA modifications that increase with age) were detected in liver, kidney, and lung. Two of these (spots 1 and 2) were chromatographically identical to the two major spots induced by Ni(II) in vitro. The intensities of spots 1 and 2 in kidney and of some other spots in liver and lung were increased 1 and 2 h after i.p. injection with a single dose of 170 mumols/kg NiAc2. The effects of NiAc2 were reduced or undetectable in the three tissues 24 h after treatment. These observations indicate the capacity of Ni(II) to induce and modulate bulky DNA modifications both in vitro and in vivo.

Topics: Animals; Ascorbic Acid; Carcinogenicity Tests; Chromatography, Thin Layer; Deuterium; Deuterium Oxide; DNA; Ferric Compounds; Free Radical Scavengers; Kidney; Liver; Lung; Male; Mice; Mice, Inbred Strains; Mutagens; Nickel; Phosphorus Isotopes; Reactive Oxygen Species; Water

We employed an electron spin resonance (ESR)2 spectrometer and used a direct detection technique for determining free radicals in circulating blood in rats. We found that the simultaneous intravenous injection of CoCl2 (10-500 mM) and ascorbic acid (100 mM) led to the formation of ascorbic acid free radicals. The potential of the Co(II) salt for producing ascorbic acid radicals was found to be dose-dependent, and was 10-fold stronger than that of a Fe(III) salt. Low height signals of the ascorbic acid radical were also observed during the simultaneous injection of NiCl2 (500 mM) and ascorbic acid (100 mM). This study clearly demonstrated that the metal ions of iron family are promoters of free radicals in vivo. These results also provide evidence to support the speculation based predominantly on in vitro experiments, that the mechanism responsible for the toxicity produced by excessive intake of transitional metal ions may involve the formation of free radicals.

Topics: Animals; Ascorbic Acid; Cobalt; Electron Spin Resonance Spectroscopy; Free Radicals; Male; Nickel; Rats; Rats, Sprague-Dawley

Recent studies have focussed on the role of thiol rich proteins especially metallothionein (MT) in the therapeutic interventions against oxidative damage. In our previous communication we showed that reactive oxygen species arising via Fenton's reactions are the proximal lipid oxidant during nickel-toxicity. The purpose of the present communication is to evaluate the role of zinc, cadmium or silver-metallothioneins on the protection against nickel-induced peroxidative damage. Our results demonstrate that Zn-MT provided maximum protection against nickel-induced mortality in mice and also served as an efficient antagonist in inhibiting nickel-mediated lipid peroxidation compared to Cd-MT or Ag-MT. Zn-MT also provided protection against iron (II)-ascorbate induced microsomal lipid peroxidation and reversed nickel-mediated inhibition of calcium sequenstration. We conclude that Zn-MT could serve as an excellent physiological antioxidant against nickel-mediated oxidative.

Topics: Animals; Ascorbic Acid; Cadmium; Cadmium Chloride; Chlorides; Drug Interactions; Ferric Compounds; Glutathione; Kinetics; Lipid Peroxidation; Metallothionein; Mice; Microsomes, Liver; Nickel; Silver Nitrate; Sulfates; Time Factors; Zinc; Zinc Sulfate

Topics: Animals; Antioxidants; Ascorbic Acid; Cytochrome P-450 Enzyme System; Guinea Pigs; In Vitro Techniques; Lung; Microsomes; Mixed Function Oxygenases; Nickel; Vitamin E

The effects of nickel subsulfide (Ni3S2) and nickel chloride [Ni(II)] on hydroxylation and deglycosylation of pure 2'-deoxyguanosine (dG) and on hydroxylation of guanine (Gu) residues in calf thymus DNA in the absence or presence of hydrogen peroxide (H2O2) and/or ascorbate (Ascb) were studied with the use of high-performance liquid chromatography. Incubation of 0.75 mM dG with 5 mg Ni3S2/ml (particle size less than 5 microns) at 37 degrees C in aerated 50 mM Tris/HCl buffer, pH 7.4, resulted in slow hydroxylation of dG to 8-hydroxy-2'-deoxyguanosine (8-OH-dG). This effect was greatly enhanced by 20 mM H2O2. Ni(II) alone at concentrations up to 10 mM was inactive but produced 8-OH-dG in the presence of 20 mM H2O2; the latter caused no dG hydroxylation by itself. Both Ni3S2 and Ni(II) increased the formation of 8-OH-dG from dG exposed to H2O2 + Ascb. At pH 7.4 and constant concentration of H2O2 and Ascb (20 and 8 mM, respectively), Ni(II) over the concentration range 1-10 mM raised the hydroxylation yield by up to five times that without Ni(II). Also, addition of 7.5 mM Ni(II) more than doubled the hydroxylation yield of Gu residues by the 20 mM H2O2 + 8 mM Ascb mixture (pH 7.4) in denatured DNA and doubled it in native DNA. Ni3S2 and Ni(II) alone had no effect on deglycosylation of dG and did not significantly influence the slow rate of Gu production from dG reacting with H2O2 or Ascb at pH 7.4. However, Ni(II), unlike Ni3S2, increased the extent of dG deglycosylation when added to the dG + H2O2 + Ascb system; 10 mM Ni(II) increased deglycosylation by a factor of 2.5 in 24 h. Thus, nickel carcinogens were shown for the first time to cause and/or enhance both hydroxylation and deglycosylation reactions of dG which may contribute to the observed genotoxic and carcinogenic effects of this metal.

Topics: Ascorbic Acid; Carcinogens; Chemical Phenomena; Chemistry; Deoxyguanosine; DNA; Hydrogen Peroxide; Hydrogen-Ion Concentration; Hydrolysis; Hydroxylation; Kinetics; Nickel