The effects of di(2-ethylhexyl)phthalate on rat liver in relation to selenium status.

This study was performed to determine the hepatotoxicity of di(2-ethylhexyl)phthalate (DEHP) in relation to selenium status. In 3-week-old Sprague-Dawley rats, selenium deficiency was induced by a ≤0.05 selenium mg/kg. A selenium supplementation group was given 1 mg selenium/kg diet for 5 weeks. Di(2-ethylhexyl)phthalate-treated groups received 1000 mg/kg dose by gavage during the last 10 days of the experiment. Histopathology, peroxisome proliferation, catalase (CAT) immunoreactivity and activity and apoptosis were assessed. Activities of antioxidant selenoenzymes [glutathione peroxidase 1 (GPx1), glutathione peroxidase 4 (GPx4), thioredoxin reductase (TrxR1)], superoxide dismutase (SOD), and glutathione S-transferase (GST); aminotransferase, total glutathione (tGSH), and lipid peroxidation (LP) levels were measured. Di(2-ethylhexyl)phthalate caused cellular disorganization while necrosis and inflammatory cell infiltration were observed in Se-deficient DEHP group (DEHP/SeD). Catalase activity and immunoreactivity were increased in all DEHP-treated groups. Glutathione peroxidase 1 and GPx4 activities decreased significantly in DEHP and DEHP/SeD groups, while GST activities decreased in all DEHP-exposed groups. Thioredoxin reductase activity increased in DEHP and DEHP/SeS, while total SOD activities increased in all DEHP-treated groups. Lipid peroxidation levels increased significantly in SeD (26%), DEHP (38%) and DEHP/SeD (71%) groups. Selenium supplementation partially ameliorated DEHP-induced hepatotoxicity; while in DEHP/SeD group, drastic changes in hepatic histopathology and oxidative stress parameters were observed.

Effects of di(2-ethylhexyl)phthalate on testicular oxidant/antioxidant status in selenium-deficient and selenium-supplemented rats.

Di(ethylhexyl)phthalate (DEHP), the most widely used plasticizer, was investigated to determine whether an oxidative stress process was one of the underlying mechanisms for its testicular toxicity potential. To evaluate the effects of selenium (Se), status on the toxicity of DEHP was further objective of this study, as Se is known to play a critical role in testis and in the modulation of intracellular redox equilibrium. Se deficiency was produced in 3-weeks-old Sprague-Dawley rats feeding them ≤0.05 mg Se /kg diet for 5 weeks, and Se-supplementation group was on 1 mg Se/kg diet. DEHP-treated groups received 1000 mg/kg dose by gavage during the last 10 days of the feeding period. Activities of antioxidant selenoenzymes [glutathione peroxidase 1 (GPx1), glutathione peroxidase 4 (GPx4), thioredoxin reductase (TrxR)], catalase (CAT), superoxide dismutase (SOD), and glutathione S-transferase (GST); concentrations of reduced glutathione (GSH), oxidized glutathione (GSSG), and thus the GSH/GSSG redox ratio; and thiobarbituric acid reactive substance (TBARS) levels were measured. DEHP was found to induce oxidative stress in rat testis, as evidenced by significant decrease in GSH/GSSG redox ratio (>10-fold) and marked increase in TBARS levels, and its effects were more pronounced in Se-deficient rats with ∼18.5-fold decrease in GSH/GSSG redox ratio and a significant decrease in GPx4 activity, whereas Se supplementation was protective by providing substantial elevation of redox ratio and reducing the lipid peroxidation. These findings emphasized the critical role of Se as an effective redox regulator and the importance of Se status in protecting testicular tissue from the oxidant stressor activity of DEHP.

Di(2-ethylhexyl)phthalate-induced renal oxidative stress in rats and protective effect of selenium.

This study was designed to examine the oxidative stress potential of di(2-ethylhexyl)phthalate (DEHP) on rat kidney and to evaluate possible protective effect of selenium (Se) status. Se deficiency (SeD) was produced in 3-week old Sprague-Dawley rats by feeding them ≤ 0.05 Se mg/kg diet for 5 weeks; Se supplementation group (SeS) was on 1 mg Se/kg diet. DEHP treated groups received 1000 mg/kg dose by gavage during the last 10 days of the feeding period. Activities of antioxidant selenoenzymes [glutathione peroxidase 1 (GPx1), glutathione peroxidase 4 (GPx4), thioredoxin reductase (TrxR)], catalase (CAT), superoxide dismutase (SOD), and glutathione S-transferase (GST); concentrations of total glutathione (GSH), thiols and thiobarbituric acid reactive substance (TBARS) levels were measured. DEHP treatment was found to induce oxidative stress in rat kidney, as evidenced by significant decreases in GPx1 (~20%) and SOD (~30%) activities and GSH levels (~20%), along with marked decrease in thiol content (~40%) and increase in TBARS (~30%) levels. The effects of DEHP was more pronounced in SeD rats, whereas Se supplementation was protective by providing substantial elevations of GPx1 and GPx4 activities and GSH levels. These findings emphasized the critical role of Se as an effective redox regulator and the importance of Se status in protecting renal tissue from the oxidant stressor activity of DEHP.

TOX4 and its binding partners recognize DNA adducts generated by platinum anticancer drugs.

Platinating agents are commonly prescribed anticancer drugs damaging DNA. Induced lesions are recognized by a wide range of proteins. These are involved in cellular mechanisms such as DNA repair, mediation of cytotoxicity or chromatin remodeling. They therefore constitute crucial actors to understand pharmacology of these drugs. To expand our knowledge about this subproteome, we developed a ligand fishing trap coupled to high throughput proteomic tools. This trap is made of damaged plasmids attached to magnetic beads, and was exposed to cell nuclear extracts. Retained proteins were identified by nanoHPLC coupled to tandem mass spectrometry. This approach allowed us to establish a list of 38 proteins interacting with DNA adducts generated by cisplatin, oxaliplatin and satraplatin. Some of them were already known interactome members like high mobility group protein 1 (HMGB1) or the human upstream binding factor (hUBF), but we also succeeded in identifying unexpected proteins such as TOX HMG box family member 4 (TOX4), phosphatase 1 nuclear targeting subunit (PNUTS), and WD repeat-containing protein 82 (WDR82), members of a recently discovered complex. Interaction between TOX4 and platinated DNA was subsequently validated by surface plasmon resonance imaging (SPRi). These interactions highlight new cellular responses to DNA damage induced by chemotherapeutic agents.

Effects of static magnetic field and cadmium on oxidative stress and DNA damage in rat cortex brain and hippocampus.

The present study was undertaken to determine the effect of co-exposure to static magnetic field (SMF) and cadmium (Cd) on the antioxidant enzymes activity and DNA integrity in rat brain. Sub-chronic exposure to CdCl (CdCl(2), 40 mg/L, per os) for 30 days resulted in a significant reduction in antioxidant enzyme activity such as the glutathione peroxidase (GPx), catalase (CAT) and superoxide dismutase (SOD) in frontal cortex and hippocampus. Total GSH were decreased in the frontal cortex of the Cd-exposed group. Cd exposure induced an increase in malondialdehyde (MDA) concentration in the frontal cortex and hippocampus. Moreover, the same exposure increased 8-oxo-7,8-dihydro-2-desoxyguanosine (8-oxodGuo) level in rat brain. Interestingly, the combined effect of SMF (128 mT, 1 hour/day for 30 consecutive days) and CdCl (40 mg/L, per os) decreased the SOD activity and glutathione level in frontal cortex as compared with the Cd group. Moreover, the association between SMF and Cd increased MDA concentration in frontal cortex as compared with Cd-exposed rats. DNA analysis revealed that SMF exposure failed to alter 8-oxodGuo concentration in Cd-exposed rats. Our data showed that Cd exposure altered the antioxidant enzymes activity and induced oxidative DNA lesions in rat brain. The combined effect of SMF and Cd increased oxidative damage in rat brain as compared with Cd-exposed rats.

Effect of selenium pre-treatment on plasma antioxidant vitamins A (retinol) and E (α-tocopherol) in static magnetic field-exposed rats.

In the present study, we evaluate the effect of the co-exposure to static magnetic field (SMF) and selenium (Se) on the antioxidant vitamins A and E levels and some other parameters of oxidative stress in rat. Sub-acute exposure of male adult rats to a uniform SMF (128 mT, 1 h/day during 5 consecutive days) increased plasma activity of glutathione peroxidase (+35%) but decreased α-tocopherol (-67%) and retinol levels (-41%). SMF exposure failed to alter the plasmatic thiobarbituric acid-reactive species (TBARs), total thiol groups and selenium concentrations. Sub-chronic administration of Se (Na(2)SeO(3), 0.2 mg/L, for 30 consecutive days, per os) ameliorated the antioxidant capacities in SMF-treated rats. Our investigation demonstrated that sub-acute exposure to SMF induced oxidative stress, which may be prevented by a pretreatment with selenium.

Incidence of cancers, ischemic cardiovascular diseases and mortality during 5-year follow-up after stopping antioxidant vitamins and minerals supplements: a postintervention follow-up in the SU.VI.MAX Study.

The Supplementation in Vitamins and Mineral Antioxidants Study was a double-blind, placebo-controlled, randomized trial, in which 12,741 French adults (7,713 women aged 35-60 years and 5,028 men aged 45-60 years) received a combination of ascorbic acid (120 mg), vitamin E (30 mg), beta-carotene (6 mg), selenium (100 microg) and zinc (20 mg), or placebo daily for a median follow-up time of 7.5 years [October 1994 to September 2002]. Antioxidant supplementation decreased total cancer incidence and total mortality in men. Postintervention follow-up assessment of total cancer incidence, ischemic cardiovascular disease incidence and total mortality was carried out for 5 years [September 1, 2002, to September 1, 2007]. No late effect of antioxidant supplementation was revealed 5 years after ending the intervention neither on ischemic cardiovascular disease incidence and mortality in both genders nor on cancer incidence in women. Regarding duration of intervention effects in men, the reduced risk of total cancer incidence and total mortality was no longer evident after the 5-year postintervention follow-up. During the postsupplementation period, the relative risk (RR) for total cancer incidence (n = 126) was 0.98 (95% confidence interval [CI], 0.75-1.27) among antioxidant recipients compared to nonrecipients. For total mortality (n = 90), the RR was 0.98 (95% CI, 0.75-1.26) for men receiving antioxidants compared to nonrecipients. In conclusion, beneficial effects of antioxidant supplementation in men disappeared during postintervention follow-up.

Evaluation of cytotoxicity and oxidative DNA damaging effects of di(2-ethylhexyl)-phthalate (DEHP) and mono(2-ethylhexyl)-phthalate (MEHP) on MA-10 Leydig cells and protection by selenium.

Di(2-ethylhexyl)-phthalate (DEHP) is the most abundantly used phthalate derivative, inevitable environmental exposure of which is suspected to contribute to the increasing incidence of testicular dysgenesis syndrome in humans. Oxidative stress and mitochondrial dysfunction in germ cells are suggested to contribute to phthalate-induced disruption of spermatogenesis in rodents, and Leydig cells are one of the main targets of phthalates' testicular toxicity. Selenium is known to be involved in the modulation of intracellular redox equilibrium, and plays a critical role in testis, sperm, and reproduction. This study was aimed to investigate the oxidative stress potential of DEHP and its consequences in testicular cells, and examine the possible protective effects of selenium using the MA-10 mouse Leydig tumor cell line as a model. In the presence and absence of selenium compounds [30 nM sodium selenite (SS), and 10 µM selenomethionine (SM)], the effects of exposure to DEHP and its main metabolite mono(2-ethylhexyl)-phthalate (MEHP) on the cell viability, enzymatic and non-enzymatic antioxidant status, ROS production, p53 expression, and DNA damage by alkaline Comet assay were investigated. The overall results of this study demonstrated the cytotoxicity and genotoxicity potential of DEHP, where MEHP was found to be more potent than the parent compound. SS and SM produced almost the same level of protection against antioxidant status modifying effects, ROS and p53 inducing potentials, and DNA damaging effects of the two phthalate derivatives. It was thus shown that DEHP produced oxidative stress in MA-10 cells, and selenium supplementation appeared to be an effective redox regulator in the experimental conditions used in this study, emphasizing the critical importance of the appropriate selenium status.

Quantitative determination of plasma vitamin K1 by high-performance liquid chromatography coupled to isotope dilution tandem mass spectrometry.

Plasma vitamin K1 (phylloquinone) determination is commonly used for the diagnosis of vitamin K deficiency in patients suffering from lipid malabsorption. Moreover, current evidence that adequate vitamin K intake, and correspondingly adequate plasma vitamin K1 concentration, could also be of importance in relation to bone and brain diseases emphasizes the need to improve the current analytical methods. We developed a liquid chromatography coupled to tandem mass spectrometry method using a stable isotope ring-D4-labeled internal standard of vitamin K1 and operating in the multiple reaction monitoring mode by the selection of a precursor and product ions. The atmospheric pressure chemical ionization (APCI) method was shown to be more sensitive than electrospray ionization. After a single-step extraction with cyclohexane, chromatographic separation was performed on a C18 column with an isocratic mobile phase. The linearity was up to 5400ng/L, and the limit of detection was 14ng/L. Intra- and interrun precision were 2.4% and 8.3%, respectively, for the lower limit of the reference range. Recovery was better than 98%. The method is simple and reliable, allowing accurate vitamin K1 measurement in plasma samples from healthy subjects and patients suffering from vitamin K deficiency.

Study of fibroblast gene expression in response to oxidative stress induced by hydrogen peroxide or UVA with skin aging.

The skin aging process, implying oxidative stress, is associated with specific gene expression. Ultraviolet A (UVA) and hydrogen peroxide (H(2)O(2)) both generate reactive oxygen species (ROS) making them relevant in the study of skin cell responses to oxidative stresses. To investigate transcript expression associated with chronological skin aging and its modulation by two oxidative stresses, cDNA micro-arrays, composed of a set of 81 expressed sequence tag (EST) clones, were used to probe the patterns of transcript expression in human fibroblasts of five young (< 21 years-old) and five older (> 50 years-old) healthy females at basal levels and 24 h after exposure to UVA (7 J/cm2) and H(2)O(2) (20 mM). At the basal state, 22% of total genes were up-regulated in the older group. Although both stresses led to the same cell mortality, H(2)O(2) induced a stronger modulation of gene expression than UVA, with 19.5% of transcripts up-regulated versus 4%. The aging process affected the response to H(2)O(2) and even though cells from old donors presented higher basal levels of transcripts they were not able to regulate them in response to the stress. Interestingly, UVA had a specific strong inhibitory effect on the expression of chemokine (C-C) motif ligand 2 (CCL2) transcript, suggesting a possible mechanism for its anti-inflammatory and immunoregulatory roles.

Differential repair of UVB-induced cyclobutane pyrimidine dimers in cultured human skin cells and whole human skin.

Cyclobutane pyrimidine dimers (CPDs) and pyrimidine (6-4) pyrimidone photoproducts (6-4PPs) are the two main classes of mutagenic DNA damages induced by UVB radiation. Numerous studies have been devoted so far to their formation and repair in human cells and skin. However, the biochemical methods used often lack the specificity that would allow the individual study of each of the four CPDs and 6-4PPs produced at TT, TC, CT and CC dinucleotides. In the present work, we applied an HPLC-mass spectrometry assay to study the formation and repair of CPDs and 6-4PPs photoproducts in primary cultures of human keratinocytes and fibroblasts as well as in whole human skin. We first observed that the yield of dimeric lesions was slightly higher in fibroblasts than in keratinocytes. In contrast, the rate of global repair was higher in the last cell type. Moreover, removal of DNA photoproducts in skin biopsies was found to be slower than in both cultured skin cells. In agreement with previous works, the repair of 6-4PPs was found to be more efficient than that of CPDs in the three types of samples, with no observed difference between the removal of the TT and TC derivatives. In contrast, a significant influence of the nature of the two modified pyrimidines was observed on the repair rate of CPDs. The decreasing order of removal efficiency was the following: C<>T>C<>C>T<>C>T<>T. These data, together with the known intrinsic mutational properties of the lesions, would support the reported UV mutation spectra. A noticeable exception concerns CC dinucleotides that are mutational hotspots with an UV-specific CC to TT tandem mutation, although related bipyrimidine photoproducts are produced in low yields and efficiently repaired.

Determination of dansylated polyamines in red blood cells by liquid chromatography-tandem mass spectrometry.

The concentration of polyamines in red blood cells (RBCs) is considered to be an index of cell proliferation. This index has been demonstrated to be of clinical importance for the follow-up and treatment of some cancer patients. The concentration of polyamines in RBCs is usually determined by high-performance liquid chromatography (HPLC) with fluorescence detection. In the current work, we present a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantification of putrescine, spermidine, and spermine, the three major polyamines in RBCs. The polyamines were dansylated and analyzed by an LC gradient of 20-min duration on a C18 column on-line with a tandem mass spectrometer. An internal standard (1,8-diaminooctane) was used for quantification. This method exhibited excellent linearity for the three polyamines with regression coefficients higher than 0.99. The limits of detection for putrescine, spermidine, and spermine were 0.10, 0.75, and 0.50 pmol/ml, respectively. The intrarun precision values for putrescine, spermidine, and spermine all were better than 10%, and the interrun precision values were 13%, 9%, and 20%, respectively. The LC-MS/MS method is sufficiently simple and reliable enough to replace the currently used HPLC method with fluorescence detection in which putrescine is not always detectable.

Total plasma carotenoids and mortality in the elderly: results of the Epidemiology of Vascular Ageing (EVA) study.

Carotenoids are pigments found in fruits and vegetables. While high intakes of fruits and vegetables have been found to be associated with lower mortality, our objective is to investigate if total plasma carotenoids, via their antioxidant properties, are associated with mortality risk in a free-living elderly population. The 'Epidemiology of Vascular Ageing' (EVA) study (n 1389; 59-71 years) is a 9-year longitudinal study with six waves of follow-up. The association between baseline total plasma carotenoids and mortality was determined by Cox proportional hazards regression analyses. Low total plasma carotenoid level was significantly associated with all-cause mortality in men but not in women. After controlling for potential confounding factors, mortality risk increased significantly in men (P = 0.03) with plasma carotenoids in the lowest quintile compared with men with plasma carotenoids in the highest (relative risk 2.94 (95% CI 1.21, 7.17)). A significant association between mortality by cancer and low plasma carotenoid level variable was also found in men (unit = 1 micromol/l; relative risk 1.72 (95% CI 1.02, 2.86); P = 0.01). Associations between total plasma carotenoids and mortality risk remained statistically significant after taking into account: (1) plasma Se level, which previously was found associated with mortality in this population and (2) thiobarbituric acid-reactive substances level considered as an indicator of oxidative stress. By showing, prospectively, in a general healthy elderly population, that total plasma carotenoid levels were independently associated with mortality risk in men, the present study suggests that total plasma carotenoid levels could be a health indicator in elderly populations.

Effect of static magnetic field and/or cadmium in the antioxidant enzymes activity in rat heart and skeletal muscle.

Currently, environmental and industrial pollution along with increase and causes multiple stress conditions, the combined exposure to magnetic field and other toxic agents is recognised as an important research area, with a view to better protecting human health against their probable unfavourable effects. In the present study, we investigated the effect of co-exposure to static magnetic field (SMF) and cadmium (Cd) on the antioxidant enzymes activity and the malondialdehyde (MDA) concentration in rat skeletal and cardiac muscles. The exposure of rats to SMF (128 mT, 1 h/day during 30 consecutive days) decreased the activities of glutathione peroxidase (GPx) and the superoxide dismutase (CuZn-SOD) in heart muscle. Sub-chronic exposure to SMF increased the MDA concentration in rat cardiac muscle. Cd treatment (CdCl2, 40 mg/l, per os) during 4 weeks decreased the activities of catalase (CAT) in skeletal muscle and the CuZn-SOD in the heart. Moreover, Cd administration increased MDA concentration in the both structures. The combined effect of SMF (128 mT, 1 h/day during 30 consecutive days) and Cd (40 mg/l, per os) disrupt the antioxidant enzymes activity in rat skeletal and cardiac muscles. Moreover, we noted a huge increase in MDA concentration in the heart and skeletal muscle compared to control group. Thus it is possible that the SMF- and/or Cd-induced depletion of antioxidant enzymes activity in muscle tissues might, like the enhanced lipid peroxidation, importantly contribute to oxidative damage. The combined effect of SMF and Cd altered significantly the antioxidant enzymatic capacity and induced lipid peroxidation in both skeletal and cardiac muscle.

Effects of static magnetic field exposure on antioxidative enzymes activity and DNA in rat brain.

The present study was undertaken in order to investigate the effects of static magnetic field (SMF) exposure on the antioxidative enzymes activity, malondialdehyde (MDA) concentration and DNA oxidation in male rat brain. The exposure of rats to SMF (128 mT, 1 h/day during 30 consecutive days) decreased the glutathione peroxidase (GPx; -39%, p < 0.05), CuZn superoxide dismutase (CuZn-SOD; -35%, p < 0.05) and catalase (-59%, p < 0.05) activities in frontal cortex. The same treatment decreased the CuZn-SOD (-51%, p < 0.05) and Mn-SOD (-13%, p < 0.05) activities in hippocampus. However, the glutathione levels remained unchanged in the both brain structures. In the hippocampus, SMF exposure increased MDA concentration (+32%, p < 0.05). Interestingly, exposed-rats to SMF displayed a significant increase of metallothioneins level in frontal cortex (+100%, p < 0.05), while the 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo) concentration remained unaffected, indicating the absence of DNA oxidation. Our results indicated that sub-chronic exposure to SMF induced oxidative stress in rat hippocampus and frontal cortex. Metallothionein induction protected probably DNA against oxidative damage.

Ciprofloxacin-induces free radical production in rat cerebral microsomes.

In the presence of ciprofloxacin (CPFX), free radical adduct formation was demonstrated in rat cerebral microsomes using a spin trap α-(4-pyridyl-1-oxide)-N-tert-butyl-nitrone by electron spin resonance spectroscopy. Active microsomes, dihydronicotinamide-adenine dinucleotide phosphate, and ciprofloxacin were necessary for the formation of a spin trap/radical adduct. Adduct formation increased dose-dependently at 0.5-1 mM CPFX concentration for 180 min, and 0.3-1 mM concentration level for 240 min. The addition of SKF 525A, ZnCl2 or desferrioxamine to the incubation system caused complete inhibition of the radical formation. However, pretreatment of microsomal system with superoxide dismutase (SOD) did not induce any protective effect. Induction of lipid peroxidation, and depletion of thiol levels by CPFX were also shown in the system. These results strongly suggested that CPFX produces free radical(s) in the cerebral microsomes of rats.

Impairment of the antioxidant properties of serum albumin in patients with diabetes: protective effects of metformin.

Free radical production is increased during diabetes. Serum albumin is a major antioxidant agent, and structural modification of albumin induced by glucose or free radicals impairs its antioxidant properties. Therefore the aim of the present study was to compare the antioxidant capacities and structural changes in albumin in patients with T2DM (Type 2 diabetes mellitus) treated with MET (metformin) or SU (sulfonylureas) and in healthy control subjects. Structural changes in albumin were studied by fluorescence quenching in the presence of acrylamide. Albumin thiols and fructosamines, reflecting oxidized and glycation-induced changes in serum albumin respectively, were assessed. Structural changes in albumin were demonstrated by a significant decrease in fluorescence quenching in patients with T2DM, with patients treated with MET exhibiting a significant difference in the conformation of albumin compared with patients treated with SU. Oxidation, resulting in a significant decrease in thiol groups and plasma total antioxidant capacity, and glycation, associated with a significant increase in fructosamines, were both found when comparing healthy control subjects with patients with T2DM. When patients treated with MET were compared with those treated with SU, oxidative stress and glycation were found to be significantly lower in MET-treated patients. In conclusion, patients with T2DM have a decrease in the antioxidant properties of serum albumin which may aggravate oxidative stress and, thus, contribute to vascular and metabolic morbidities. Moreover, a significant protection of albumin was found in patients with T2DM treated with MET.

Cadmium-induced oxidative stress and DNA damage in kidney of pregnant female rats.

In the present study, we have investigated the influence of sub-acute treatment with cadmium (Cd) on some parameters indicative of oxidative stress and DNA damage in tissues of pregnant female rats. Pregnant female rats (n=6) were injected subcutaneously, daily with a dose of cadmium chloride of 3 mg/kg body weight (b.w.) from day 6 to day 19 of pregnancy, and they were allowed to deliver normally. MDA level and GPx, CAT and SOD activities were used as markers of oxidative stress in liver and kidney. The 8-oxo-dG level was measured by the HPLC-EC system. Cd treatment increased MDA (+116%, p<0.01) in kidney. Moreover, Cd treatment also decreased CuZn-SOD (-11%, p<0.05) and GSH level (-52%, p<0.05) in kidney. Treated rats displayed an increase of the liver metallothionein (MT) level. Induction of MT in liver was probably implicated in the detoxification of Cd. The high level of Cd (3 mg/kg) used in the present study is partially neutralized by MT in liver, whereas the free fraction could be implicated in the oxidative stress and DNA oxidation observed in kidney. Cd treatment failed to alter 8-oxodGuo, indicating the absence of DNA oxidation in liver; by contrast, the same treatment increased the 8-oxodGuo level (+51%, p<0.05) in the kidney of pregnant female rats, indicating an oxidative stress associated with DNA damage only in kidney.

Relationships between different types of fruit and vegetable consumption and serum concentrations of antioxidant vitamins.

Increased fruit and vegetable consumption has become a health priority in many countries. Therefore, data investigating the influence of different types of fruits and vegetables on serum antioxidant levels would be useful. The objective of the study was to assess the relationship between fruit and vegetable consumption and vitamin serum antioxidant concentrations. Specific fruit and vegetable groups are evaluated. A total of 3521 subjects (1487 men and 2034 women), aged 35-60 years, participating in the SU.VI.MAX cohort were included in this study. Blood samples of participants were analysed for beta-carotene, vitamin C and alpha-tocopherol. Each subject had completed at least six dietary records during the first 2 years of the study. It was found that women had higher mean beta-carotene and vitamin C serum concentrations than men, but lower alpha-tocopherol serum concentrations. Serum beta-carotene and vitamin C concentrations were positively correlated with consumption of both fruit and vegetables, as well as with most of the fruit and vegetable groups tested. These relationships persisted after adjustment for confounding factors. Regression analysis showed a linear dose-response relationship. Root vegetables and citrus fruits were particularly associated with beta-carotene serum status as were citrus fruits for vitamin C. Fruit and vegetable consumption was either not or weakly associated with alpha-tocopherol serum concentrations. These results describe antioxidant serum concentrations according to fruit and vegetable consumption in a large sample and support the findings of previous studies involving a more limited number of subjects.

Genotoxicity of combined exposure to polycyclic aromatic hydrocarbons and UVA--a mechanistic study.

Solar UV radiation and benzo[a]pyrene (BaP) are two carcinogenic agents. When combined, their deleterious properties are synergistic. In order to get insights into the underlying processes, we carried out a mechanistic study within isolated DNA photosensitized to UVA radiation by either BaP, its diol epoxide metabolite (BPDE) or the tetraol arising from the hydrolysis of this last molecule. Measurement of the level of the oxidized base 8-oxo-7,8-dihydroguanine revealed that BaP is a poor sensitizer while BPDE and tetraol are more potent ones. None of these compounds was found to photosensitize formation of cyclobutane pyrimidine dimers through triplet energy transfer. On the basis of the distribution of oxidized DNA bases, we could show that photosensitization of DNA by BPDE involves electron abstraction (Type I) while tetraol acts mainly through singlet oxygen production (Type II). Under our experimental conditions, Type I was the major photosensitization process, which shows the lack of involvement of tetraol in the observed photo-oxidation reaction. Finally, we could show that the adducts, resulting from the alkylation of DNA by BPDE, are very potent sensitizers. Indeed, they are located in the close vicinity of the double helix and thus perfectly placed to induce oxidation reactions.