The influence of ascorbic acid on nickel-induced hepatic lipid peroxidation in rats

Associations of nickel exposure with diabetes: evidence from observational studies

The results of environmental epidemiological studies regarding the relationship between human exposure to nickel and the risk of diabetes remain controversial. Therefore, we performed a meta-analysis to investigate the relationship between nickel exposure and diabetes. PubMed, Web of Science, and Embase electronic databases were thoroughly searched from their inception to May 2023 to obtain relevant studies. The random-effects model was employed to determine pooled odds ratios (ORs) and 95% confidence intervals (CIs). Stratified and sensitivity analyses were also performed. Cochran Q test and I2 statistic were employed to assess heterogeneity between studies. Begg's and Egger's tests were employed to evaluate publication bias. The indicated studies were evaluated using the ROBINS-E risk of bias tool. The dose-response relationship between nickel in urine and diabetes risk was estimated by restricted cubic spline. A total of 12 studies with 30,018 participants were included in this study. In this meta-analysis, comparing the highest vs. lowest levels of nickel exposure, the pooled ORs for diabetes were 1.42 (95% confidence interval 1.14-1.78) for urine and 1.03 (0.57-1.86) for blood, respectively. A linear relationship between urinary nickel and diabetes risk was discovered in the dose-response analysis (P nonlinearity = 0.6198). Each 1 µg/L increase of urinary nickel, the risk of diabetes increased by 7% (OR = 1.07, 95% CI 1.04-1.10). The risk of diabetes was positively correlated with urine nickel exposure, whereas the risk was not significantly correlated with blood nickel. In the future, more high-quality prospective studies are needed to validate this conclusion.

Urinary Nickel Was Associated with the Prevalence of Diabetes: Results from NHANES

The study aimed to investigate the association between nickel exposure and the presence of diabetes (DM). The participants were analyzed from the National Health and Nutrition Examination Surveys (NHANES) 2017-2018. Urinary nickel exposure was measured using inductively coupled-plasma mass spectrometry. DM was diagnosed based on the WHO standards. The association between nickel and DM or fasting glucose was examined using multivariable linear regression models and logistic regression models. A total of 1899 participants (933 men and 966 women) were included in our study, of whom 342 (18.0%) were diagnosed with DM. There was a significant positive association between nickel level and DM (OR: 1.27, 95%CI: 1.04-1.56) after adjusting for potential confounding factors. Comparing with the lowest quartile, the highest quartile independently increased a 0.66-fold higher risk of DM (OR: 1.66, 95%CI: 1.13-2.44]). In addition, nickel exposure was independently related to the level of fasting glucose. The exposure to nickel was associated with a higher risk of DM in general population.

Nickel and Oxidative Stress: Cell Signaling Mechanisms and Protective Role of Vitamin C

BACKGROUND

Nickel activates the signaling pathways through the oxygen sensing mechanism and the signaling cascades that control hypoxia-inducible transcriptional gene expressions through oxidative stress. This review emphasizes on the recent updates of nickel toxicities on oxidant and antioxidant balance, molecular interaction of nickel and its signal transduction through low oxygen microenvironment in the in-vivo physiological system.

DISCUSSION

Nickel alters intracellular chemical microenvironment by increasing ionized calcium concentration, lipid peroxidation, cyclooxygenase, constitutive nitric oxide synthase, leukotriene B4, prostaglandin E2, interleukins, tumor necrosis factor-α, caspases, complement activation, heat shock protein 70 kDa and hypoxia-inducible factor-1α. The oxidative stress induced by nickel is responsible for the progression of metastasis. It has been observed that nickel exposure induces the generation of reactive oxygen species which leads to the increased expression of p53, NF-kβ, AP-1, and MAPK. Ascorbic acid (vitamin C) prevents lipid peroxidation, oxidation of low-density lipoproteins and advanced oxidation protein products. The mechanism involves that vitamin C is capable of reducing ferric iron to ferrous iron in the duodenum, thus the availability of divalent ferrous ion increases which competes with nickel (a divalent cation itself) and reduces its intestinal absorption and nickel toxicities.

CONCLUSION

Reports suggested the capability of ascorbic acid as a regulatory factor to influence gene expression, apoptosis and other cellular functions of the living system exposed to heavy metals, including nickel.

Preliminary study of oxidative stress biomarkers and trace elements in North Sea Harbour Seals

This preliminary study investigated the potential correlations between trace elements (mercury, zinc, cadmium, copper, selenium, lead, nickel, chromium, lithium and vanadium) concentrations, measured in red blood cells, and oxidative stress biomarkers (total thiols, total glutathione, total and selenium-dependent glutathione peroxidases, triglycerides, malondialdehyde) assessed in the respective serum, in males and females P. vitulina, sampled in the Wadden Sea in spring and autumn 2015. Only concentrations of total mercury and zinc showed significant differences by sex, and only lipid peroxidation was different by season. Moreover, significant positive and negative correlations were observed between biomarkers (triglycerides, thiols, malondialdehyde, glutathione) and trace element concentrations (copper, lead, mercury, nickel, zinc). These findings suggest that the studied biomarkers could be useful for the assessment of oxidative stress in harbour seals exposed to trace elements, but further research with larger sample sizes is needed to better understand their specific associations.

Exposure to variable doses of nickel oxide nanoparticles disturbs serum biochemical parameters and oxidative stress biomarkers from vital organs of albino mice in a sex-specific manner

INTRODUCTION

This study was designed to report the biological effect of nickel oxide nanoparticles (NiO NPs) in albino mice.

MATERIAL AND METHODS

Five weeks old albino mice of both sex were intraperitoneally injected either with 20 mg (low dose) or 50 mg/mL saline/kg body weight (high dose) of NiO NPs for 14 days. Saline-treated controls were maintained in parallel. Complete blood count, selected serum biochemical parameters and oxidative stress biomarkers from vital organs were determined in all subjects.

RESULTS

Male mice treated with NiO NPS had increased blood urea nitrogen, elevated superoxide dismutase (SOD) in liver elevated MDA in liver, kidney and heart and reduced catalase activity in heart and kidney. Female mice treated with NiO NPs had significantly reduced serum albumin and total proteins, SOD in lungs and elevated MDA in liver.

DISCUSSION

We are reporting that intraperitoneal injections of NiO NPs for 14 days drastically affect blood serum parameters and oxidative stress biomarkers from vital organs of albino mice.

CONCLUSION

Toxic effects of NiO NPs were dose and sex dependent and they were more pronounced at higher dose and in male mice.

Effect of L-Ascorbic Acid on Nickel-Induced Alteration of Cardiovascular Pathophysiology in Wistar Rats

Nickel, a widely used heavy metal is suspected as a cardiotoxic element. The aim of the present study was to assess the possible protective role of l-ascorbic acid on nickel-induced alterations of cardiovascular pathophysiology in male albino rats. Twenty-four albino rats (b.wt. 170-250 g) were randomized into four groups: control; l-ascorbic acid (50 mg/100 g b.wt., orally); NiSO₄ (2.0 mg/100 g b.wt., i.p.); NiSO₄ with l-ascorbic acid. Cardiovascular electrophysiology, serum and cardiac tissue malondialdehyde (MDA), nitric oxide (NO), ascorbic acid, serum α-tocopherol and serum vascular endothelial growth factor (VEGF) were evaluated. Histopathology of cardiac and aortic tissues was also assessed. NiSO₄-treated rats showed a significant increase in heart rate, LF/HF ratio and blood pressure (SBP, DBP and MAP). A significant increase of serum MDA, NO and VEGF in NiSO₄ treatment with a concomitant decrease of serum ascorbic acid and α-tocopherol as compared to their respective controls were also observed. Simultaneous supplementation of l-ascorbic acid with NiSO₄ significantly decreased LF/HF ratio, BP and oxidative stress parameters, whereas ascorbic acid and α-tocopherol concentration was found to be increased. Histopathology of cardiac and aortic tissues showed nickel-induced focal myocardial hypertrophy and degeneration in cardiac tissue with focal aneurism in aortic tissues. Supplementation with l-ascorbic showed a protective action in both cardiac and aortic tissues. Results indicated the possible beneficial effect of l-ascorbic acid on nickel-induced alteration of the cardiovascular pathophysiology in experimental rats.

Effects of Nickel Supplementation on Antioxidant Status, Immune Characteristics, and Energy and Lipid Metabolism in Growing Cattle

Nickel (Ni) has not been elucidated as an essential mineral in dairy animals, though in plants and lower organisms, its role in activation of urease enzyme is well known. This study was conducted to evaluate the effect of Ni supplementation on intake, growth performance, urease activity, antioxidant and immune status, and energy and lipid metabolism in growing cattle. Eighteen growing Hariana heifers were randomly allocated into three groups on body weight (125 ± 3.0 kg) and age basis (10 ± 2.0 months). Feeding regimen was similar in all the groups except that treatment groups were supplemented with 0.0 (Ni_0.0), 1.5 (Ni_1.5), and 3.0 (Ni_3.0) mg of Ni/kg dry matter (DM) in three respective groups. DM intake (DMI), average daily gain (ADG), feed efficiency, plasma urease activity, biomarkers of antioxidant and immune status, energy and lipid metabolism, and plasma Ni levels were observed during the 90-day experimental period. There was linear increase (p < 0.05) in mean DMI and ADG without affecting feed efficiency was observed in 3.0 mg of Ni/kg DM supplemented heifers. Dietary Ni supplementation showed linear increase (p < 0.05) in mean plasma urease activity. No effects of (p > 0.05) of Ni supplementation were observed on superoxide dismutase (SOD) and catalase (CAT) activity and plasma lipid peroxide (LPO) concentration; whereas, mean plasma total antioxidant status (TAS) showed linear decrease (p < 0.001) in Ni-supplemented groups. Adding Ni up to 3.0 mg of Ni/kg DM did not exert (p > 0.05) any effect on plasma total immunoglobulin and immunoglobulin G (IgG) concentrations. Mean plasma cortisol level showed negative association with supplemental Ni levels and concentration was found lowest (p < 0.05) in 3.0 mg of Ni/kg DM-added group. Dietary Ni supplementation did not affect mean plasma concentrations of glucose, cholesterol, triglyceride, and non-esterified fatty acids (NEFA). There was a linear increase (p < 0.001) in plasma Ni concentrations as the Ni concentrations increased in the diet. The results of present study indicated that dietary supplementation of 3.0 mg of Ni/kg DM improved performance of growing cattle by increasing urease activity.

Effects of Protocatechuic Acid (PCA) on Global Cerebral Ischemia-Induced Hippocampal Neuronal Death

Global cerebral ischemia (GCI) is one of the main causes of hippocampal neuronal death. Ischemic damage can be rescued by early blood reperfusion. However, under some circumstances reperfusion itself can trigger a cell death process that is initiated by the reintroduction of blood, followed by the production of superoxide, a blood⁻brain barrier (BBB) disruption and microglial activation. Protocatechuic acid (PCA) is a major metabolite of the antioxidant polyphenols, which have been discovered in green tea. PCA has been shown to have antioxidant effects on healthy cells and anti-proliferative effects on tumor cells. To test whether PCA can prevent ischemia-induced hippocampal neuronal death, rats were injected with PCA (30 mg/kg/day) per oral (p.o) for one week after global ischemia. To evaluate degenerating neurons, oxidative stress, microglial activation and BBB disruption, we performed Fluoro-Jade B (FJB), 4-hydroxynonenal (4HNE), CD11b, GFAP and IgG staining. In the present study, we found that PCA significantly decreased degenerating neuronal cell death, oxidative stress, microglial activation, astrocyte activation and BBB disruption compared with the vehicle-treated group after ischemia. In addition, an ischemia-induced reduction in glutathione (GSH) concentration in hippocampal neurons was recovered by PCA administration. Therefore, the administration of PCA may be further investigated as a promising tool for decreasing hippocampal neuronal death after global cerebral ischemia.

Nickel exposure is associated with the prevalence of type 2 diabetes in Chinese adults

BACKGROUND

Nickel exposure can induce hyperglycaemia in rodents, but little is known about its association with abnormal glucose metabolism in humans. We aimed to investigate the association of nickel exposure with the prevalence of type 2 diabetes in Chinese adults.

METHODS

A total of 2115 non-institutionalized men and women aged 55 to 76 years from Beijing and Shanghai were included, and urinary nickel concentration was assessed by inductively coupled plasma mass spectroscopy. The prevalence of type 2 diabetes was compared across urinary nickel quartiles. Fasting plasma glucose, insulin, lipids, C-reactive protein and glycated haemoglobin A1c, as well as urinary albumin and creatinine were measured.

RESULTS

The median concentration of urinary nickel was 3.63 mg/l (interquartile range: 2.29–5.89 mg/l), and the prevalence of diabetes was 35.3% (747 cases/2115 persons). Elevated levels of urinary nickel were associated with higher fasting glucose, glycated haemoglobin A1c, insulin and homeostatic model assessment of insulin resistance (all P<0.01). The odds ratios (95% confidence interval) for diabetes across the increasing urinary nickel quartiles were 1.27 (0.97–1.67), 1.78 (1.36–2.32) and 1.68 (1.29–2.20), respectively (referencing to 1.00), after multivariate adjustment including lifestyle factors, body mass index and family history of diabetes (P for trend <0.001). The association remained unchanged after further controlling for urinary creatinine and C-reactive protein (P for trend <0.001).

CONCLUSIONS

Increased urinary nickel concentration is associated with elevated prevalence of type 2 diabetes in humans.

Liver Toxicity of Cadmium Telluride Quantum Dots (CdTe QDs) Due to Oxidative Stress in Vitro and in Vivo

With the applications of quantum dots (QDs) expanding, many studies have described the potential adverse effects of QDs, yet little attention has been paid to potential toxicity of QDs in the liver. The aim of this study was to investigate the effects of cadmium telluride (CdTe) QDs in mice and murine hepatoma cells alpha mouse liver 12 (AML 12). CdTe QDs administration significantly increased the level of lipid peroxides marker malondialdehyde (MDA) in the livers of treated mice. Furthermore, CdTe QDs caused cytotoxicity in AML 12 cells in a dose- and time-dependent manner, which was likely mediated through the generation of reactive oxygen species (ROS) and the induction of apoptosis. An increase in ROS generation with a concomitant increase in the gene expression of the tumor suppressor gene p53, the pro-apoptotic gene Bcl-2 and a decrease in the anti-apoptosis gene Bax, suggested that a mitochondria mediated pathway was involved in CdTe QDs' induced apoptosis. Finally, we showed that NF-E2-related factor 2 (Nrf2) deficiency blocked induced oxidative stress to protect cells from injury induced by CdTe QDs. These findings provide insights into the regulatory mechanisms involved in the activation of Nrf2 signaling that confers protection against CdTe QDs-induced apoptosis in hepatocytes.

Cocos nucifera (L.) (Arecaceae): A phytochemical and pharmacological review

Cocos nucifera (L.) (Arecaceae) is commonly called the “coconut tree” and is the most naturally widespread fruit plant on Earth. Throughout history, humans have used medicinal plants therapeutically, and minerals, plants, and animals have traditionally been the main sources of drugs. The constituents of C. nucifera have some biological effects, such as antihelminthic, anti-inflammatory, antinociceptive, antioxidant, antifungal, antimicrobial, and antitumor activities. Our objective in the present study was to review the phytochemical profile, pharmacological activities, and toxicology of C. nucifera to guide future preclinical and clinical studies using this plant. This systematic review consisted of searches performed using scientific databases such as Scopus, Science Direct, PubMed, SciVerse, and Scientific Electronic Library Online. Some uses of the plant were partially confirmed by previous studies demonstrating analgesic, antiarthritic, antibacterial, antipyretic, antihelminthic, antidiarrheal, and hypoglycemic activities. In addition, other properties such as antihypertensive, anti-inflammatory, antimicrobial, antioxidant, cardioprotective, antiseizure, cytotoxicity, hepatoprotective, vasodilation, nephroprotective, and anti-osteoporosis effects were also reported. Because each part of C. nucifera has different constituents, the pharmacological effects of the plant vary according to the part of the plant evaluated.

The effects of heavy metals and their interactions with polycyclic aromatic hydrocarbons on the oxidative stress among coke-oven workers

Heavy metals and polycyclic aromatic hydrocarbons (PAHs) are predominate toxic constituents of particulate air pollution that may be related to the increased risk of cardiopulmonary events. We aim to investigate the effects of the toxic heavy metals (arsenic, As; cadmium, Cd; chromium, Cr; nickel, Ni; and lead, Pb), and their interactions with PAHs on oxidative stress among coke-oven workers. A total of 1333 male workers were recruited in this study. We determined their urinary levels of As, Cd, Cr, Ni, Pb, twelve PAH metabolites, 8-hydroxydeoxyguanosine (8-OHdG), and 8-iso-prostaglandin-F2α (8-iso-PGF2α). Multivariate linear regression models were used to analyze the effects of these metals and their interactions with PAHs on 8-OHdG and 8-iso-PGF2α levels. It was found that only urinary As and Ni showed marginal or significant positive linear dose-dependent effects on 8-OHdG in this study population, especially among smokers (β=0.103, P=0.073 and β=0.110, P=0.002, respectively). After stratifying all participants by the quartiles of ΣOH-PAH, all five metals showed linear association with 8-OHdG in the highest quartile subgroup (Q4) of ΣOH-PAHs. However, these five urinary metals showed significantly consistent linear associations with 8-iso-PGF2α in all subjects and each stratum. Urinary ΣOH-PAHs can significant modify the effects of heavy metals on oxidative stress, while co-exposure to both high levels of ΣOH-PAHs and heavy metals render the workers with highest 8-OHdG and 8-iso-PGF2α (all P(interaction)≤0.005). This study showed evidence on the interaction effects of heavy metals and PAHs on increasing the oxidative stress, and these results warrant further investigation in more longitudinal studies.

Detoxification of rats subjected to nickel chloride by a biomaterial-based carbonated orthophosphate

Recently, the therapeutic approaches of the detoxification against the metals (nickel) in the body are the use of biomaterials such as carbonated hydroxyapatite. The aim of this study is therefore to analyze the physiological and physicochemical parameters of strain white rats "Wistar" receiving nickel chloride and to study the protective associative of apatite against adverse effects of this metal, and this in comparison with control rats. Our results showed that the nickel induced in rats an oxidative stress objectified by elevated levels of thiobarbituric acid-reactive substances and conjugated dienes associated with inhibition of the activity of the antioxidant defense system such as glutathione peroxidase, superoxide dismutase and catalase in the liver, kidney, spleen and erythrocyte. Disorders balances of ferric, phosphocalcic, a renal failure and a liver toxicity were observed in rats exposed to nickel. As well as a significant increase in the rate of nickel in the bones and microcytic anemia was revealed. However, the implantation of carbonated hydroxyapatite in capsule form protects rats intoxicated by the nickel against the toxic effects of this metal by lowering the levels of markers of lipid peroxidation and improving the activities of defense enzymes. Our implantation technique is effective to correct ferric balance and phosphocalcic equilibrium, to protect liver and kidney function, to reduce the rate of bone nickel and to correct anemia. They clearly explain the beneficial and protective of our biomaterial which aims the detoxification of rats receiving nickel by substituting cationic (Ca(2+) by Ni(2+)) and anionic (OH(-) by Cl(-)) confirmed by physicochemical characterization like the IR spectroscopy and X-ray diffraction. These techniques have shown on the one hand a duplication of OH(-) bands (IR) and on the other hand the increase of the volume of the apatite cell after these substitutions (X-ray diffraction).

Ameliorating effects of troxerutin on nickel-induced oxidative stress in rats

OBJECTIVE

This study investigates the effects of troxerutin on nickel (Ni)-induced oxidative stress in rats.

METHODS

Nickel as nickel sulfate (20 mg/kg body weight (b.w.)) was administered intraperitoneally for 20 days to induce toxicity in the subject rats. The levels of stress markers AST, ALT, ALP, LDH, and GGT in the hepatic tissue were significantly increased while a decrease in the levels of enzymic and non-enzymic antioxidants was observed in Ni intoxicated rats.

RESULTS

Oral administration of troxerutin along with Ni for 20 days in a dose-dependent manner significantly reverted the stress markers in the liver tissue to near normal level. Troxerutin exhibited significant protection at 100 mg/kg b.w. Histopathological studies also supported the above findings.

CONCLUSIONS

Thus, we conclude that troxerutin preserved the histo-architecture and ameliorated stress markers in the liver tissue of Ni-intoxicated rats.

Beneficial role of naringin, a flavanoid on nickel induced nephrotoxicity in rats

This study was conducted to investigate the beneficial role of naringin on nickel induced nephrotoxicity. Nickel (Ni) (20mg/kg body weight (b.w.) was administered intraperitoneally (i.p.) for 20 days. Naringin was administered orally (20, 40 and 80 mg/kg b.w.) with i.p. administration of Ni. Ni administration increased the levels of serum urea, uric acid and creatinine with a significant decrease in creatinine clearance and decreased levels of urea, uric acid and creatinine in urine. The levels of lipid peroxidation markers and nickel concentration in blood and kidney were also increased. While, the activities of enzymic and non-enzymic antioxidants were decreased. Treatment with naringin attenuated the alterations in the renal and urine markers, decreasing lipid peroxidation markers, increasing the antioxidant cascade and decreasing the nickel concentration in blood and kidney. All these changes were supported by histopathological observations. These findings demonstrate that naringin exerts a protective effect against nickel toxicity.

L-ascorbic acid and α tocopherol supplementation and antioxidant status in nickel- or lead-exposed rat brain tissue

We evaluated the effect of L-ascorbic acid and alpha-tocopherol supplementation on plasma and whole brain nitric oxide level and antioxidant status in nickel sulfate- or lead acetate- treated male albino rats. Nitric oxide and lipid peroxide levels in whole brain tissue and plasma increased following nickel and lead treatment but significantly returned to near-normal values upon L-ascorbic acid or alpha-tocopherol supplementation. In brain tissue, antioxidant enzymes--superoxide dismutase, glutathione peroxidase, glutathione peroxidase, and catalase--along with the glutathione level decreased significantly after both treatments but significantly improved upon simultaneous supplementation with L-ascorbic acid or alpha-tocopherol. Lead-treated animals showed a greater improvement with alpha-tocopherol, whereas nickel-treated rats showed a greater improvement with L-ascorbic acid. In both groups, combined supplementation with L-ascorbic acid and alpha-tocopherol did not change the percentage improvement in comparison with supplementation with a single vitamin alone.

Hepatoprotective role of naringin on nickel-induced toxicity in male Wistar rats

Aim of the present study was planned to determine the protective role of naringin in attenuating the toxicity induced by nickel sulfate in rat liver. In this investigation nickel sulfate (20mg/kg body weight) was administered intraperitoneally for 20days to induce toxicity. Naringin was administered orally (20, 40 and 80mg/kg body weight) for 20days with intraperitoneal administration of nickel sulfate. Liver injury was measured by the increased activities of serum hepatic enzymes namely aspartate transaminase, alanine transaminase, alkaline phosphatase, gamma glutamyl transferase, lactate dehydrogenase and total bilirubin along with increased elevation of lipid peroxidation markers, thiobarbituric reactive acid substances, lipid hydroperoxides, protein carbonyl content and conjugated dienes. The toxic effect of nickel was also indicated by significantly decreased activities of enzymatic antioxidants like superoxide dismutase, catalase, glutathione peroxidase, glutathione-S-transferase, glutathione reductase and glucose-6-phosphate dehydrogenase and non-enzymatic antioxidants like reduced glutathione, total sulfhydryl groups, vitamin C and vitamin E levels were significantly decreased. Naringin administered at a dose of 80mg/kg body weight significantly reversed the activities of hepatic marker enzymes, decreasing lipid peroxidative markers, increasing the antioxidant cascade and decreasing the nickel concentration in the liver. The effect at a dose of 80mg/kg body weight was more pronounced than that of other two doses (20 and 40mg/kg body weight). All these changes were supported by histopathological observations. These results clearly demonstrate that naringin has the potential in alleviating the toxic effects of nickel in rat liver.

Ameliorative effect of curcumin on hepatotoxicity induced by chloroquine phosphate

India is one of the most endemic areas, where malaria predominates and its control has become a formidable task. Chloroquine phosphate (CQ) on account of its rapid action on blood schizontocide of all the malarial parasite strains has become the most widely prescribed drug for prophylaxis and treatment of malaria. Toxicity of CQ is most commonly encountered at therapeutic and higher doses of treatment. Thus, the present study was undertaken to evaluate the protective effect of Curcumin, a herbal antioxidant obtained from Curcuma longa, on hepatic biochemical and histopathological status of CQ induced male mice. Swiss albino male mice were administered oral doses of CQ (100mg/kg body wt., 200mg/kg body wt. and 300mg/kg body wt.) and CQ+curcumin (300mg/kg body wt.+80mg/kg body wt.) for 45 days. A withdrawal of high dose treatment for 45 days was also studied. Administration of CQ brought about a significant decrease in Protein content with a decline in SDH, ATPase and ALKase activities, whereas ACPase activity was found to be significantly increased following CQ treatment. Antioxidant enzyme SOD registered a significant reduction as opposed to TBARS which was found to be elevated in a significant manner in the CQ treated groups as compared to control. Gravimetric indices (body weight and organ weight) declined significantly following CQ treatment. Administration of curcumin exhibited significant reversal of CQ induced toxicity in hepatic tissue. Protein content, SDH, ATPase, ALKase, ACPase, SOD, TBARS, body weight and organ weight were found to be comparable to that of control group after curcumin administration. Thus, obtained results led us to conclude the curative potential of curcumin against CQ induced hepatotoxicity.

Effect of garlic (Allium sativum) on heavy metal (nickel II and chromium VI) induced alteration of serum lipid profile in male albino rats

We have studied the effect of simultaneous oral treatment of aqueous garlic extract (Allium sativum) on heavy metal (nickel II and chromium VI) induced changes in serum lipid profile. Nickel sulfate and potassium dichromate treated rats showed a significant increase in serum low density lipoprotein-cholesterol (LDL-C), very low density lipoprotein-cholesterol (VLDL-C) and triglyceride (TG) level as well as decrease in serum high density lipoprotein-cholesterol (HDL-C) level. Simultaneous garlic administration with nickel sulfate showed improvement in serum LDL-C, HDL-C, VLDL-C and TG level. But in case of potassium dichromate, garlic administration did not show satisfactory improvement in lipid profile except VLDL-C and TG level. The results indicate that garlic (Allium sativum) has some beneficial effect in preventing heavy metal (nickel and chromium VI) induced alteration of lipid profile.

Protective effect of cactus (Opuntia ficus indica) cladode extract upon nickel-induced toxicity in rats

The purpose of this study carried out on male Wistar rats, was to evaluate the protective effects of regular ingestion of juice from the prickly pear cactus (Opuntia ficus indica) cladodes against nickel chloride toxicity. Rats were given either normal tap water or water containing 25% of cactus juice for one month. Then, rats of each group were injected daily, for 10 days, with either NiCl(2) solution (4mg (30micromol)/kg body weight) or with the same volume of saline solution (300mM NaCl). Significant increases of lactate dehydrogenase, aspartate aminotransferase, alanine aminotransferase activities and of cholesterol, triglycerides and glucose levels were observed in blood of nickel-treated rats. In the liver, nickel chloride was found to induce an oxidative stress evidenced by an increase in lipid peroxidation and changes in antioxidant enzymes activities. Superoxide-dismutase (SOD) activity was found to be increased whereas glutathione peroxidase and catalase activities were decreased. These changes did not occur in animals previously given cactus juice, demonstrating a protective effect of this vegetal extract.

Efficacy of caffeic acid in preventing nickel induced oxidative damage in liver of rats

Nickel (Ni), a major environmental pollutant, is known for its wide toxic manifestations. In the present study caffeic acid (CA), one of the most commonly occurring phenolic acids in fruits, grains and dietary supplements, was evaluated for its protective effect against the Ni induced oxidative damage in liver. In this investigation, Ni (20 mg/kg body weight) was administered intraperitoneally for 20 days to induce toxicity. CA was administered orally (15, 30 and 60 mg/kg body weight) for 20 days with intraperitoneal administration of Ni. Ni induced liver damage was clearly shown by the increased activities of serum hepatic enzymes namely aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), gamma glutamyl transferase (GGT) and lactate dehydrogenase (LDH) along with increased elevation of lipid peroxidation indices (thiobarbituric reactive acid substances (TBARS) and lipid hydroperoxides). The toxic effect of Ni was also indicated by significantly decreased levels of enzymatic (superoxide dismutase (SOD), catalase (CAT) glutathione peroxidase (GPx) and glutathione S-transferase (GST)) and non-enzymatic antioxidants (glutathione (GSH), vitamin C and vitamin E). CA administered at a dose of 60 mg/kg body weight significantly reversed the activities of hepatic marker enzymes to their near normal levels when compared with other two doses. In addition, CA significantly reduced lipid peroxidation and restored the levels of antioxidant defense in the liver. All these changes were supported by histological observations. The results indicate that CA may be beneficial in ameliorating the Ni induced oxidative damage in the liver of rats.

Effect of lead (Pb) exposure on the activity of superoxide dismutase and catalase in battery manufacturing workers (BMW) of Western Maharashtra (India) with reference to heme biosynthesis

The aim of this study was to estimate the activity of superoxide dismutase (SOD) and catalase in erythrocytes and malondialdehyde (MDA) in plasma of battery manufacturing workers (BMW) of Western Maharashtra (India) who were occupationally exposed to lead (Pb) over a long period of time (about 15 years). This study was also aimed to determine the Pb intoxication resulted in a disturbance of heme biosynthesis in BMW group. The blood Pb level of BMW group (n = 28) was found to be in the range of 25.8 - 78.0 microg/dL (mean + SD, 53.63 + 16.98) whereas in Pb unexposed control group (n = 35) the range was 2.8 - 22.0 microg/dL (mean + SD, 12.52 + 4.08). The blood level (Pb-B) and urinary lead level (Pb-U) were significantly increased in BMW group as compared to unexposed control. Though activated d- aminolevulinic acid dehydratase (ALAD) activities in BMW group did not show any significant change when compared to control group but activated / non activated erythrocyte - ALAD activities in BMW group showed a significant increase. Erythrocyte- zinc protoporphyrin (ZPP), urinary daminolevulinic acid (ALA-U) and porphobilinogen (PBG-U) of BMW groups elevated significantly as compared to control. A positive correlation (r = 0.66, p < 0.001) between Pb-B and ALA-U were found in BMW group but no such significant correlation (r = 0.02, p> 1.0) were observed in control group. Hematological study revealed a significant decrease of hemoglobin concentration, packed cell volume (%) and other blood indices and a significant increase of total leucocytes count in BMW group in comparison to control group. The serum MDA content was significantly increased (p < 0.001) and the activities of antioxidant enzymes such as erythrocyte- SOD (p < 0.001) and erythrocytecatalase (p < 0.001) were significantly reduced in BMW group as compared to control group. A positive correlation (r = 0.45, p < 0.02) between Pb-B and serum MDA level was observed in BMW group (Pb-B range 25.8 - 78.0 microg / dL) but such significant correlation did not notice in control group (Pb-B range 2.8 - 22.0 microg / dL). The study clearly showed an adverse effect of heme biosynthesis and imbalance of pro-oxidant / antioxidant status in lead exposed battery manufacturing workers resulting in increase in lipid peroxidation associated with decrease in erythrocyte-SOD and erythrocyte-catalase activities.

Hepatoprotective effect ofHygrophila spinosa andCassia occidentalis on carbon tetrachloride induced liver damage in experimental rats

The present study was undertaken to analyze the levels of some known antioxidant (both enzymic and non enzymic) activities in the rootsof Hygrophila spinosa andCassia occidentalis also to find out the hepatoprotective effect of the same in carbon tetrachloride induced liver damage in albino rats. The roots were found to be rich in antioxidants. Liver damage in rats were induced by carbon tetrachloride. To find out the hepatoprotective activity, the aqueous extract of the plant root samples were administrated to rats for 15 days. The serum marker enzymes Aspartate transaminase, Alanine transaminase and Gama Glutamyl were measured in experimental animals. The increased enzyme levels after liver damage with carbon tetrachloride were nearing to normal value when treated with aqueous extract of the root samples. Histopathological observation also proved the hepatoprotectivity of the root samples.

Effect of nickel exposure on peripheral tissues: role of oxidative stress in toxicity and possible protection by ascorbic acid

The vast industrial use of nickel has led to environmental pollution by the metal and its by-products during production, recycling, and disposal. Nickel is a known hematotoxic, immunotoxic, hepatotoxic, pulmotoxic, and nephrotoxic agent. Allergic skin reactions are common in individuals who are sensitive to nickel. This article presents a selective review on nickel and its effect on certain metabolically active peripheral tissues of human and animals. The subtopics include nickel sources and uses, exposure pathways, transport, excretion, general health effects, and specific acute and chronic nickel toxicities in peripheral tissues like liver, lungs, and kidneys. The review particularly addresses the nickel-induced generation of reactive oxygen species and increased lipid peroxidation in various metabolically active tissues in humans and animals, and the possible role of vitamin c as a protective antioxidant.

Biochemical aspects of lead exposure in silver jewelry workers in western Maharashtra (India)

This study was conducted to examine the effect of blood lead (Lead) on heme biosynthesis, the hematopoietic system, oxidative stress, and antioxidant status of silver jewelry workers (SJW) in western Maharastra (India). The blood lead level of the SJW group (N = 30) was in the range of 30.2-64.7 microg dL(-1) (mean +/- SD, 48.56 +/- 7.39 microg dL(-1)), whereas that of non-occupational Lead-exposed normal healthy control subjects (N = 35) was 2.8-22.0 microg dL(-1) (mean +/- SD, 12.52 +/- 4.08 microg dL(-1)). Although the blood lead level of the SJW group increased significantly (p < 0.001) when compared with the control group, the urinary excretion of lead in the SJW group was not altered. In the SJW group, non-activated delta-aminolevulinic acid dehydratase (ALAD) activity significantly decreased (p < 0.05), and the ratio of activated/non-activated ALAD increased when compared with controls (p < 0.001), whereas activated ALAD activity was not altered significantly. Erythrocyte zinc protoporphyrin (ZPP) was not altered in SJW. The urinary excretion of delta-amino-levulinic acid (p < 0.001) and porpobilinogen (p < 0.05) of the SJW group increased significantly when compared with controls. Hematology parameters, such as the packed cell volume (p < .001) and total erythrocyte count (p < 0.05) significantly decreased, whereas the mean corpuscular hemoglobin concentration (p <.001) and total white blood cell count (p < .001) increased in the SJW group in comparison with controls. The serum malondialdehyde content significantly increased (p < .001), and the activities of antioxidant enzymes erythrocyte-SOD (p < .001), erythrocyte catalase (p < .05), and plasma ceruloplasmin (p < .001) significantly decreased in the SJW group compared with the controls. The results of the study clearly show an alteration of heme biosynthesis and cellular impairment of the pro-oxidants/antioxidants balance, resulting in oxidative damage in the silver jewelry workers group in western Maharashtra (India).

Effect of l-ascorbic acid on antioxidant defense system in testes of albino rats exposed to nickel sulfate

We studied the effect of oral supplementation with L-ascorbic acid (50 mg/100 g body weight) on nickel sulfate (2.0 mg/100 g body weight, i.p.) induced lipid peroxidation in the testes of Wister strain male albino rats. Testicular lipid peroxide and glutathione (GSH) levels and the activities of the antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) were estimated. Nickel sulfate treatment significantly increased the level of testicular lipid peroxide and decreased all antioxidant enzymes activities and GSH concentration. Simultaneously treatment of L-ascorbic acid exhibited a possible protective role on the toxic effect of nickel sulfate on testicular lipid peroxide and GSH concentration as well as antioxidant enzymatic defense system.

Effect of L-ascorbic acid on nickel-induced alterations in serum lipid profiles and liver histopathology in rats

Nickel exposure greatly depletes intracellular ascorbate and alters ascorbate-cholesterol metabolism. We studied the effect of the simultaneous oral treatment with L-ascorbic acid (50 mg/100 g body weight (BW) and nickel sulfate (2.0 mg/100 g BW, i.p) on nickelinduced changes in serum lipid profiles and liver histopathology. Nickel-treated rats showed a significant increase in serum low-density lipoprotein-cholesterol, total cholesterol, triglycerides, and a significant decrease in serum high-density lipoprotein-cholesterol. In the liver, nickel sulfate caused a loss of normal architecture, fatty changes, extensive vacuolization in hepatocytes, eccentric nuclei, and Kupffer cell hypertrophy. Simultaneous administration of L-ascorbic acid with nickel sulfate improved both the lipid profile and liver impairments when compared with rats receiving nickel sulfate only. The results indicate that L-ascorbic acid is beneficial in preventing nickel-induced lipid alterations and hepatocellular damage.

L-ascorbic acid protects the antioxidant defense system in nickel-exposed albino rat lung tissue

We studied the effect of oral supplementation with L-ascorbic acid (50 mg /100 g body weight (BW) on nickel sulfate (2.0 mg/ 100 g BW, i.p)-induced lipid peroxidation and histopathology in the lung of Wister strain male albino rats. Lipid peroxide and glutathione levels and the activities of the antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px), were estimated. Nickel sulfate administration significantly increased the level of lipid peroxides and decreased all antioxidant enzyme activities. Nickel sulfate treatment also induced (a) loss of normal characteristics and architectural organization, (b) inflammation in bronchioles, (c) alveolar congestion, (d) alveolar cell hyperplasia, and (e) congestion in the lumen. The simultaneous administration of L-ascorbic acid and nickel sulfate improved both lipid peroxidation and the histopathology of lung when compared with rats receiving nickel sulfate alone. The results indicate that L-ascorbic acid prevents nickel-induced alteration of antioxidant defense mechanisms and histopathology of lung tissue.

Ascorbate depletion: a critical step in nickel carcinogenesis?

Nickel compounds are known to cause respiratory cancer in humans and induce tumors in experimental animals. The underlying molecular mechanisms may involve genotoxic effects; however, the data from different research groups are not easy to reconcile. Here, we challenge the common premise that direct genotoxic effects are central to nickel carcinogenesis and probably to that of other metals. Instead, we propose that it is formation of metal complexes with proteins and other molecules that changes cellular homeostasis and provides conditions for selection of cells with transformed phenotype. This is concordant with the major requirement for nickel carcinogenicity, which is prolonged action on the target tissue. If DNA is not the main nickel target, is there another unique molecule that can be attacked with carcinogenic consequences? Our recent observations indicate that ascorbate may be such a molecule. Nickel depletes intracellular ascorbate, which leads to the inhibition of cellular hydroxylases, manifested by the loss of hypoxia-inducible factor (HIF)-1alpha and -2alpha hydroxylation and hypoxia-like stress. Proline hydroxylation is crucial for collagen and extracellular matrix assembly as well as for assembly of other protein molecules that have collagen-like domains, including surfactants and complement. Thus, the depletion of ascorbate by chronic exposure to nickel could be deleterious for lung cells and may lead to lung cancer. Key words: ascorbate, carcinogenesis, collagens, extracellular matrix, hypoxia-inducible transcription factor, metals, nickel, protein hydroxylation.

Protective role of zinc in nickel induced hepatotoxicity in rats

This study was planned to determine the protective role of zinc, if any, in attenuating the toxicity induced by nickel sulfate in rat liver. Female Sprague Dawley (SD) rats received either nickel alone in the dose of 800 mg/l in drinking water, zinc alone in the dose of 227 mg/l in drinking water, and nickel plus zinc or drinking water alone for a total duration of eight weeks. The effects of different treatments were studied on various parameters in rat liver which include antioxidant enzymes, levels of nickel and zinc and histoarchitecture at the light microscopic level. Further, the activities of hepatic marker enzymes AST and ALT were also studied in rat serum. Nickel treatment to the normal control animals, resulted in a significant increase in lipid peroxidation and enzyme activities of catalase and glutathione-S-transferase. On the contrary, nickel treatment to normal rats caused a significant inhibition in the levels of reduced glutathione. Superoxide dismutase activity was found to be decreased which however was not significant. Interestingly, when Zn was supplemented to nickel treated rats, the activities of catalase, and glutathione-S-transferase and the levels of GSH and lipid peroxidation came back to within normal limits. Activities of serum AST and ALT were increased significantly following nickel treatment to normal rats. Simultaneous zinc administration to nickel treated rats tended to restore the altered levels of AST and ALT. Normal control and zinc treated animals revealed normal histology of liver. On the other hand, nickel treated animals showed alterations in normal hepatic histoarchitecture which comprise of vacuolization of the hepatocytes and dilatation of sinusoids as well as increase in the number of bi-nucleated cells. Administration of zinc to nickel treated rats resulted in marked improvement in the structure of hepatocytes, thus emphasizing the protective potential of zinc in restoring the altered hepatic histoarchitecture. The nickel administration to normal rats indicated increased concentrations of nickel and decreased concentrations of zinc. However, zinc effectively brought the altered levels of nickel and zinc to within normal range. The study concludes that zinc has the potential in alleviating the toxic effects of nickel in rat liver because of its property to induce metallothionein (S-rich protein) as a free radical scavenger, or its indirect action in reducing the levels of oxygen reactive species.

Potential role of vitamins in chromium induced spermatogenesis in Swiss mice

Chromium (Cr) (VI) compounds are known carcinogens and mutagens. The mechanism of carcinogenicity and mutagenicity caused by chromium(VI) compounds remained unclear for several years. However, in the recent past chromium-induced carcinogenicity and/or mutagenicity was known to happen due to the generation of reactive oxygen species (ROS). In the present context, chromic acid (CrO(3)), a potential Cr(VI) compound could be able to generate reactive oxygen radicals in the testes of Swiss mice as evidenced from significantly higher lipid peroxidation compared to untreated controls. The cytotoxic effects of the compound on the testes are depicted in terms of significantly reduced sperm count level accompanied with increased abnormal sperm population in treated mice. Supplementation of vitamins like Vitamin C and Vitamin E (Vit C and Vit E) to CrO(3) injected mice groups could partially prevent the incidence of abnormal sperm population and increased the sperm count. Of the two vitamins, taken for the study, Vit C happens to be more effective in ameliorating germ cells from degeneration and from mutation to abnormal sperm. Possible antioxidative role of both the vitamins have been studied for significant decrease in lipid peroxidation associated with marked elevation in sperm count level and significant decrease in the percentage of abnormal sperm formation in CrO(3)-treated mice.

Studies on the role of ascorbic acid on nickel induced hepatic nucleic acid concentrations in rats

We studied the effect of oral treatment with ascorbic acid (50 mg/100 g body weight) on nickel sulfate-induced (2.0 mg/100 g body weight, i.p.) alteration of nucleic acids and total protein concentration in the liver of Wistar strain male albino rats. Nucleic acids and total protein concentrations in treated rats decreased significantly when compared with untreated controls. The simultaneous administration of ascorbic acid with nickel sulfate resulted in a remarkable improvement of nucleic acids and total protein concentrations in liver in comparison with rats treated with nickel sulfate only. The results indicate that nickel influences the expression of genetic information by reducing hepatic DNA, RNA, and protein concentration in animals. Simultaneous treatment with ascorbic acid was beneficial for fighting against nickel-induced hepatoxicity.