The effect of vitamin C on bisphenol A, nonylphenol and octylphenol induced brain damages of male rats

The Influence of Manganese and Glutamine Intake on Antioxidants and Neurotransmitter Amino Acids Levels in Rats' Brain

Depending on the concentration, Mn can exert protective or toxic effect. Potential mechanism for manganese neurotoxicity is manganese-induced oxidative stress. Glutamine supplementation could reduce manganese-induced neurotoxicity and is able to influence the neurotransmission processes. The aim of this study was to investigate whether the long term administration of manganese (alone or in combination with glutamine) in dose and time dependent manner could affect the selected parameters of oxidative-antioxidative status (superoxide dismutase and glutathione peroxidase activities, concentrations of vitamin C and malonic dialdehyde) and concentrations of excitatory (Asp, Glu) and inhibitory amino acids (GABA, Gly) in the brain of rats. The experiments were carried out on 2-months-old albino male rats randomly divided into 6 group: Mn300 and Mn500—received solution of MnCl₂ to drink (dose 300 and 500 mg/L, respectively), Gln group—solution of glutamine (4 g/L), Mn300-Gln and Mn500-Gln groups—solution of Mn at 300 and 500 mg/L and Gln at 4 g/L dose. The control group (C) received deionized water. Half of the animals were euthanized after three and the other half—after 6 weeks of experiment. The exposure of rats to Mn in drinking water contributes to diminishing of the antioxidant enzymes activity and the increase in level of lipid peroxidation. Glutamine in the diet admittedly increases SOD and GPx activity, but it is unable to restore the intracellular redox balance. The most significant differences in the examined amino acids levels in comparison to both control and Gln group were observed in the group of rats receiving Mn at 500 mg/L dose alone or with Gln. It seems that Gln is amino acid which could improve antioxidant status and affect the concentrations of the neurotransmitters.

Short-term effect of bisphenol-a on oxidative stress responses in Atlantic salmon kidney cell line: a transcriptional study

Bisphenol A (BPA) is regularly detected in aquatic ecosystems due to increased use of products based on polycarbonate plastics and epoxy resins. It migrates from these products directly into rivers and marine waters or indirectly through effluents from wastewater treatment plants and landfilled sites. BPA can affect aquatic organisms both chronically and acutely at sensitive live stages. Despite reports indicating harmful effects of BPA, little is known about its role in oxidative stress responses in fish. In this study, we investigated the transcriptional effect of BPA (0, 1, 10, 100 μM) on an Atlantic salmon kidney (ASK) cell line for 6 h and 24 h by monitoring expression of 11 genes: elongation factor 1-alpha (ef1a), 18S ribosomal RNA (18s), gluthation (gsh), superoxide dismutase (sod), thioredoxin (txd), Salmo salar oxidative stress-responsive serine-rich 1 (oxr), glucose-regulated protein 78 (grp78), heat shock protein 70 (hsp70), sequestosome1 (p62), interleukin-1 beta (il-1beta) and toll-like receptor 8 (tlr8). In general, only the 100 μM concentration treatment altered the mRNA expression. BPA down-regulated the expression of gsh and sod genes for both exposure-times while txd gene was the only down-regulated after 6-h exposure. The up-regulation of genes in the ASK cell line exposed for 6 h was only observed in il-1beta, while the 24-h exposure resulted in the up-regulation of oxr, tlr8, hsp70, p62 and il-1beta genes. The last three genes increased several fold compared to the others. The results showed that BPA exposure at 100 μM imposed oxidative stress on the ASK cell line and longer exposure time involved transcriptional responses of immune-related genes. This may indicate the possible role of BPA-associated oxidative stress in induction of inflammatory response in this macrophage-like cell type.

Cytotoxic effects of 4-octylphenol on fish hepatocytes

The present study was conducted to determine cytotoxic effects of 4-octylphenol (4-OP) on primary cultured hepatocytes of pearl mullet (Alburnus tarichi). Lactate dehydrogenase (LDH) release, malondialdehyde (MDA) level, antioxidant enzymes [superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione-S-transferase (GST)] and glutathione (GSH) content were measured after 24-h exposure to 4-OP. 4-OP caused dose- and time-dependent increases in LDH release. Significant induction of MDA level and decrease in GSH content were found. SOD and GPx activities were decreased while GST activity was increased. These findings suggest that 4-OP leads to cytotoxicity by depressing antioxidant defenses in fish hepatocytes.

A use of homology modeling and molecular docking methods: to explore binding mechanisms of nonylphenol and bisphenol A with antioxidant enzymes

Bisphenol A (BPA) and nonylphenol (NP) are phenolic compounds used widely by the industries. BPA and NP are endocrine disruptors possessing estrogenic properties. Several studies have reported that BPA and NP induce oxidative stress in various organs or cell types in animals, by inhibiting the activities of antioxidant enzymes like catalase, superoxide dismutase, glutathione peroxidase, and glutathione reductase. However, it is not understood how BPA and NP interact with these enzymes and inhibit their functions. Hence, it would be significant to check, whether binding sites are available for NP and BPA in antioxidant enzymes. In the present study three-dimensional structures of antioxidant enzymes, catalase, superoxide dismutase, glutathione peroxidase, and glutathione reductase were modeled and docked with BPA and NP. Docking studies revealed that BPA and NP have binding pockets in the antioxidant enzymes. Among the antioxidant enzymes, Catalase was maximally inhibited by BPA and superoxide was maximally inhibited by NP.

Thymoquinone attenuates toxicity and oxidative stress induced by bisphenol A in liver of male rats

Bisphenol A (BPA) is a fairly ubiquitous compound which has a great concern to human health. The current study was designed to (1) Assess the adverse effect of oral administration of BPA on liver of male rats and (2) Evaluate the role of thymoquinone (TQ), the major bioactive ingredient in the oil of Nigella sativa seed, in alleviating the possible detrimental effects of BPA on the liver. Rats were divided into control group administered olive oil, BPA group administered 10 mg BPA kg(-1) day(-1), TQ group administered 10 mg TQ kg(-1) day(-1) and BPA-TQ group administered the same previous doses of both BPA and TQ. After 24 h of the last dose, rats were decapitated and blood and liver were collected to determine some oxidative stress and biochemical parameters. Bisphenol A elicited a significant elevation in lipid peroxidation concomitant with depletion of antioxidant defense system in hepatic tissue. It also induced liver dysfunction as indicated by altered liver function markers and biochemical parameters. The administration of TQ attenuated the BPA-induced oxidative stress, alleviated the antioxidative system and improved to a large extent the liver functioning. This data clearly indicates that TQ has the potential to be a protective agent against oxidative stress and liver injury.

Ameliorating effect of chicory (Chichorium intybus L.) fruit extract against 4-tert-octylphenol induced liver injury and oxidative stress in male rats

The current study was carried out to elucidate the modulating effect of chicory (Cichorium intybus L.) fruit extract (CFR) against 4-tert-OP induced oxidative stress and hepatotoxicity in male rats. Rats were divided into four groups and treated for 8 weeks as follow: group 1: normal control-treated (saline); group 2: chicory fruit extract-treated (100 mg/kg); group 3: 4-tert-OP treated; group 4: 4-tert-OP plus chicory fruit extract. The obtained results revealed that rats which received 4-tert-OP showed a significant increase in liver TBARS and bilirubin, aspartate aminotransferase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP) and gamma-glutamyl transpeptidase (GGTP) activities. While a significant decrease in the levels of GSH, SOD, catalase recorded. On the other hand, CFR extract succeeded to modulate these observed abnormalities resulting from 4-tert-OP as indicated by the reduction of TBARS and the pronounced improvement of the investigated biochemical and antioxidant parameters. Histopathological evidence, together with observed PCNA and DNA fragmentation, supported the detrimental effect of 4-tert-OP and the ameliorating effect of CFR extract on liver toxicity. So, it could be concluded that chicory has a promising role and it worth to be considered as a natural substance for ameliorating the oxidative stress and hepatic injury induced by 4-tert-OP compound.

Therapeutic effect of pectin on octylphenol induced kidney dysfunction, oxidative stress and apoptosis in rats

Octylphenol (OP) is one of ubiquitous pollutants in the environment. It belongs to endocrine-disrupting chemicals (EDC). It is used in many industrial and agricultural products. Pectin is a family of complex polysaccharides that function as a hydrating agent and cementing material for the cellulose network. The aim of this study was to evaluate the therapeutic effect of pectin in kidney dysfunction, oxidative stress and apoptosis induced by OP exposure. Thirty-two male albino rats were divided into four equal groups; group 1 control was injected intraperitoneally (i.p) with saline [1 ml/kg body weight (bwt)], groups 2, 3 & 4 were injected i.p with OP (50 mg/kg bwt) three days/week over two weeks period where groups 3 & 4 were injected i.p with pectin (25 or 50 mg/kg bwt) three days/week over three weeks period. The results of the present study revealed that OP significantly decreased glutathione-S-transferase (GST), glutathione peroxidase (GPx), catalase (CAT), reduced glutathione (GSH), glutathione reductase (GR) and superoxide dismutase (SOD) levels while increased significantly lipid peroxidation (MDA), nitric oxide (NO) and protein carbonyls (PC) levels in the kidney tissues. On the other hand, OP increased serum urea and creatinine. Furthermore, OP increased significantly serum uric acid but decreased significantly the kidney weight. Moreover, OP decreased p53 expression while increased bcl-2 expression in the kidney tissue. The treatment with either dose of pectin to OP-exposed rats restores all the above parameters to approach the normal values where pectin at higher dose was more effective than lower one. These results were supported by histopathological investigations. In conclusion, pectin has antioxidant and anti-apoptotic activities in kidney toxicity induced by OP and the effect was dose-dependent.

Nonylphenol effects on the HPA axis of the bioindicator vertebrate, Podarcis sicula lizard

Nonylphenol (NP) is an endocrine disruptor widely distributed in the environment. It accumulates in the lipids of living organisms and enters the human food chain. The main source of human exposure is expected to be food, drinking water and foodstuff contaminated through leaching from packaging or pesticide formulation applications. NP acts as an estrogenic compound and it is able to mimic the action of estradiol 17β (E2) by binding to the estrogen receptor (ER). The aim of the present study was to investigate the NP effects on the hypothalamic-pituitary-adrenal gland (HPA) axis of the bioindicator Podarcis sicula lizard. A time-dependent stimulation of the HPA axis and variations of both catecholamine plasma levels were showed. Moreover, NP effects on adrenal gland morphology were evaluated by light and transmission electron microscopy. Clear morphological signs of adrenal gland stimulation such as an increase of steroidogenic cord diameter and vascularization, a strong escalation of adrenaline cell number and a decrease of noradrenaline cells were observed. The notably elevated levels of adrenal hormones suggested a permanent turning on of hypothalamic corticotropin releasing factor (CRF) secretion together with a lack of the negative feedback of HPA axis, perturbing systemic responses of the organism. Our data may help to predict the biological alterations induced by NP and to extend its impact upon adrenal function.

Studies on the potential protective effect of cinnamon against bisphenol A- and octylphenol-induced oxidative stress in male albino rats

Among the numerous chemicals discharged into the surrounding environment, bisphenol A (BPA) and octylphenol (OP) have been shown to increase oxidative stress in body by disturbing the prooxidant/antioxidant balance of cells. Cinnamon aqueous extract (CAE) is a natural product rich in polyphenolic compounds that have antioxidant activity. This study was designed to investigate the protective efficacy of CAE against oxidative disorders induced by BPA and OP in male albino rats. Animals were divided into 6 groups (10 rats each) and treated orally, 3 times weekly for 50 days. Group 1: control vehicle (olive oil); group 2 (25 mg BPA/kg b.wt./day); group 3 (25 mg OP/kg b.wt./day); group 4 (200 mg CAE/kg b.wt./day); group 5 (CAE 2 h before BPA administration); and group 6 (CAE 2 h before OP administration). BPA- and OP-exposed groups showed insignificant elevation in the final body weight; weight gains and significant reduction only in the relative kidneys weight. Also, BPA and OP exposure resulted in significant increase in serum urea, creatinine and kidney, brain, testicular malondialdehyde (MDA) levels. Significant reduction in tissues reduced glutathione (GSH) contents; catalase (CAT) and superoxide dismutase (SOD) activities were also recorded in BPA and OP exposed animals compared to the control vehicle group. Pretreatment with CAE 2 h either before BPA or OP administration ameliorated the BPA- and OP-induced body weight; weight gains and relative organs weight changes and biochemical adverse effects. CAE pretreatment also protected against the recorded pathological changes in kidney, brain and testis. In conclusion, CAE could ameliorate the oxidative toxic effects of BPA and OP indicating its protective antioxidant effect.

Bisphenol A and human chronic diseases: current evidences, possible mechanisms, and future perspectives

Bisphenol-A (BPA) is one of the highest volume chemicals produced worldwide, with over 6billion pounds produced and over 100t released into the atmosphere each year. Recent extensive literature has raised concerns about its possible implication in the etiology of some human chronic diseases such as diabetes, obesity, reproductive disorders, cardiovascular diseases, birth defects, chronic respiratory and kidney diseases and breast cancer. In this review, we present the highlighted evidences on the relationship between BPA exposure and human chronic diseases and we discuss its eventual mechanisms of action, especially genetic, epigenetic and endocrine disruption mechanisms with the possible involvement of oxidative stress, mitochondrial dysfunction and cell signaling.

Parental phenols exposure and spontaneous abortion in Chinese population residing in the middle and lower reaches of the Yangtze River

Widespread use of phenols has led to ubiquitous exposure to phenols. In experimental animals, phenols increased resorptions, reduced live litter size and fetal body weights. However, there are limited epidemiological evidences of the relationships between exposure to phenols and pregnancy outcomes. We evaluated the associations between parental urinary levels of various phenols and spontaneous abortion in a Chinese population residing in the middle and lower reaches of the Yangtze River. A case-control study was conducted that included 70 case couples with medically unexplained spontaneous abortion and 180 control couples who did not have a history of spontaneous abortion and had at least one living child. Both parental urinary phenols were measured by ultra-high performance liquid chromatography-tandem mass spectrometry including bisphenol A (BPA), benzophenone-3 (BP-3), 2,3,4-trichlorophenol (2,3,4-TCP), pentachlorophenol (PCP), 4-n-octylphenol (4-n-OP) and 4-n-nonylphenol (4-n-NP). Compared with the low exposure group, there was an increased risk of spontaneous abortion with high paternal urinary PCP concentration [odds ratio (OR)=2.09, 95% Confidence Interval (CI), 1.05-4.14], and maternal exposure to 4-n-OP and alkylphenol(s) also significantly increased the risk of spontaneous abortion (OR=2.21, 95% CI, 1.02-4.80; OR=2.81, 95% CI, 1.39-5.65, respectively). Our study firstly provides the evidence that paternal PCP exposure, maternal 4-n-OP and alkylphenol(s) exposure are associated with spontaneous abortion in humans.

Endocrine-disrupting chemicals and male reproductive health

Endocrine-disrupting chemicals are substances present in the environment that can interfere with normal hormonal balance and thus exert potentially adverse health effects on the human organism. Male reproductive system development and function may be susceptible to the effects of such environmental toxicants. Bisphenol A, phthalates and alkylphenols are important components of multiple products and are thus ubiquitously present in the environment. It has been demonstrated under laboratory conditions that they can exert detrimental effects on the male reproductive system. However, human exposure data are scarce and do not uniformly support toxicity of these substances at environmental concentrations. Despite substantial research efforts, the final answer to the problem of endocrine-disrupting chemicals is not yet in sight.

Bisphenol A induces hepatotoxicity through oxidative stress in rat model

Reactive oxygen species (ROS) are cytotoxic agents that lead to significant oxidative damage. Bisphenol A (BPA) is a contaminant with increasing exposure to it and exerts both toxic and estrogenic effects on mammalian cells. Due to limited information concerning the effect of BPA on liver, this study investigates whether BPA causes hepatotoxicity by induction of oxidative stress in liver. Rats were divided into five groups: The first four groups, BPA (0.1, 1, 10, 50 mg/kg/day) were administrated orally to rats for four weeks. The fifth group was taken water with vehicle. The final body weights in the 0.1 mg group showed a significant decrease compared to control group. Significant decreased levels of reduced glutathione, superoxide dismutase, glutathione peroxidase, glutathione-S-transferase, glutathione reductase and catalase activity were found in the 50 mg BPA group compared to control groups. High dose of BPA (50 mg/kg) significantly increased the biochemical levels of ALT, ALP and total bilirubin. BPA effect on the activity of antioxidant genes was confirmed by real time PCR in which the expression levels of these genes in liver tissue were significantly decrease compared to control. Data from this study demonstrate that BPA generate ROS and reduce the antioxidant gene expression that causes hepatotoxicity.

Alfa-lipoic acid protects testosterone secretion pathway and sperm quality against 4-tert-octylphenol induced reproductive toxicity

The protective effect of α-lipoic acid (LA) (50 mg/kg bw) against 4-tert-octylphenol (OP) (50 mg/kg bw) induced reproductive toxicity in male rats was studied. LA was injected 1h prior to OP administration three times a week. OP caused significant increase in oxidative stress in hypothalamus and epididymal sperm, disturbed hormonal levels in serum, decreased sperm quality, increased DNA fragmentation and loss of 35 and 95 kDa proteins in sperm, as well as elevated proliferating index in testis. LA protected against oxidative stress through promoting the levels of glutathione and glutathione-S-transferase in hypothalamus and sperm. In addition, LA prevented the decrease in testosterone, dehydroepiandrosterone sulfate, 3β-hydroxysteroid dehydrogenase, and inhibited the elevations in sex-hormone-binding globulin levels and showed normal sperm quality. LA modulated proliferation of germ cell, protected against DNA fragmentation and maintained membrane protein organization in the sperm. In conclusion, LA normalized oxidative stress and protected testosterone synthesis pathway across hypothalamus-testicular axis and sperm quality indicating its defensive influence against OP-induced oxidative reproductive dysfunction in male rats.

The use of cortical spreading depression for studying the brain actions of antioxidants

OBJECTIVES

We review the main adverse effects of reactive oxygen species (ROS) in the mammalian organism, introducing the reader on the worldwide problem of the ROS neurophysiological impact on the developing and the adult brain, and discussing the neuroprotective action of antioxidant molecules.

METHODS

We briefly present the electrophysiological phenomenon designated as 'cortical spreading depression' (CSD), as a parameter of normal brain functioning. We highlight recent electrophysiological advances obtained in experimental studies from our laboratory and from others, showing how to investigate the ROS effects on the brain by using the CSD phenomenon.

RESULTS

Under conditions such as aging, ROS production by photo-activation of dye molecules and ethanol consumption, we describe the effects, on CSD, of treating animals with (1) antioxidants and (2) with antioxidant-deficient diets.

DISCUSSION

The current understanding of how ROS affect brain electrophysiological activity and the possible interaction between these ROS effects and those effects of altered nutritional status of the organism are discussed.

Long-term exposure to nonylphenol affects insulin signaling in the liver of adult male rats

In the present study, we sought to investigate the long-term effects of nonylphenol (NP) on insulin signaling and glucose metabolism in liver. Furthermore, reactive oxygen species (ROS) in liver was evaluated as it is known to induce insulin resistance. Rats were administered NP by oral gavage at the doses of 15, 150 and 1500 μg/ kg body weight per day for 45 days. Hydrogen peroxide (H(2)O(2)) generation and lipid peroxidation were increased, and the activities of antioxidant enzymes were decreased in the liver of NP-treated rats. NP increased the plasma glucose and insulin levels and altered the enzymes of carbohydrate metabolism. Decrease in the protein levels of insulin signaling molecules insulin receptor (IR), IR substrate (IRS)-1, IRS-2 and phosphatidylinositol-3-kinase were observed with parallel increase in H(2)O(2) levels in the liver of NP-treated rats. These results suggest that NP downregulates insulin signaling in liver, which could be due to ROS production and oxidative damage.

Vitamin C coadministration augments bisphenol A, nonylphenol, and octylphenol induced oxidative damage on kidney of rats

The aim of this study was to investigate whether bisphenol A (BPA), nonylphenol (NP), and octylphenol (OP) induce oxidative stress on the kidney tissue of male rats and whether coadministration of vitamin C, an antioxidant, can prevent any possible oxidative stress. The Wistar male rats were divided into seven groups, including control, BPA, NP, OP, BPA+C, NP + C, OP +C. BPA, NP, and OP (25 mg/kg/day) was administered alone; vitamin C (60 mg/kg/day) was administered along with BPA, OP, and NP to the rats for 50 days. There was a decrease in serum concentration of blood urea nitrogen (BUN) in NP and OP groups compared with control group. Vitamin C coadministration with BPA, NP, and OP did not produce significant increase in BUN concentration in BPA +C, NP+ C, and OP + C group as compared with BPA, NP, and OP groups, respectively. The lowest serum creatinine activity and the highest lactate dehydrogenase (LDH) activity was present in kidney of BPA+C, NP+C and OP+C groups compared with BPA, NP, and OP groups. The malondialdehyde (MDA) levels were significantly higher while glutathione (GSH) levels were lower in treatment groups than controls. Furthermore, an increase was observed in MDA levels whereas a decrease was observed in GSH levels in BPA+ C, NP + C, and OP+ C groups compared with BPA, NP, and OP groups, respectively. These finding are in accordance with immunohistochemical staining of MDA and GSH. Histopathological examination of the kidneys of rats in BPA, OP, NP, BPA+ C, NP + C, and OP+ C groups revealed necrotic lesions, congestion, and mononuclear cell infiltration. In conclusion BPA, NP, and OP might induce oxidative damage in kidney of rats. In addition, coadministration of vitamin C with BPA, NP, and OP to male rats augments this damage in the kidney of male rats.

Regulation and dysregulation of vitellogenin mRNA accumulation in daphnids (Daphnia magna)

The induction of vitellogenin in oviparous vertebrates has become the gold standard biomarker of exposure to estrogenic chemicals in the environment. This biomarker of estrogen exposure also has been used in arthropods, however, little is known of the factors that regulate the expression of vitellogenin in these organisms. We investigated changes in accumulation of mRNA products of the vitellogenin gene Vtg2 in daphnids (Daphnia magna) exposed to a diverse array of chemicals. We further evaluated the involvement of hormonal factors in the regulation of vitellogenin expression that may be targets of xenobiotic chemicals. Expression of the Vtg2 gene was highly responsive to exposure to various chemicals with an expression range spanning approximately four orders of magnitude. Chemicals causing the greatest induction were piperonyl butoxide, chlordane, 4-nonylphenol, cadmium, and chloroform. Among these, only 4-nonylphenol is recognized to be estrogenic. Exposure to several chemicals also suppressed Vtg2 mRNA levels, as much as 100-fold. Suppressive chemicals included cyproterone acetate, acetone, triclosan, and atrazine. Exposure to the estrogens diethylstilbestrol and bisphenol A had little effect on vitellogenin mRNA levels further substantiating that these genes are not induced by estrogen exposure. Exposure to the potent ecdysteroids 20-hydroxyecdysone and ponasterone A revealed that Vtg2 was subject to strong suppressive control by these hormones. Vtg2 mRNA levels were not significantly affected from exposure to several juvenoid hormones. Results indicate that ecdysteroids are suppressors of vitellogenin gene expression and that vitellogenin mRNA levels can be elevated or suppressed in daphnids by xenobiotics that elicit antiecdysteroidal or ecdysteroidal activity, respectively. Importantly, daphnid Vtg2 is not elevated in response to estrogenic activity.

Behavioral impairment and oxidative damage induced by chronic application of nonylphenol

Nonylphenol (NP) is a degradation product of nonylphenol polyethoxylates, which are widely used in the production of industrial and consumer surfactants. The aim of the present study was to evaluate the effect of NP on the antioxidant capacity and cognitive ability of mice. NP was given orally by gavages at doses of 0, 50, 100, and 200 mg kg⁻¹ d⁻¹ for 90 days. The results showed that NP significantly decreased the activity of superoxide dismutases (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR) and at the same time increased malondialdehyde (MDA) levels in mice brains. Exploration, memory function and ability to learn a novel task were significantly decreased in NP fed mice. These results indicate that chronic high dose of NP exposure has the potential to generate oxidative stress and induce the cognitive impairment in male mice.

Developmental and metabolic brain alterations in rats exposed to bisphenol A during gestation and lactation

In recent years, considerable research has focused on the biological effect of endocrine-disrupting chemicals. Bisphenol A (BPA) has been implicated as an endocrine-disrupting chemical (EDC) due to its ability to mimic the action of endogenous estrogenic hormones. The aim of this study was to assess the effect of perinatal exposure to BPA on cerebral structural development and metabolism after birth. BPA (1mg/l) was administered in the drinking water of pregnant dams from day 6 of gestation until pup weaning. At postnatal day 20, in vivo metabolite concentrations in the rat pup hippocampus were measured using high field proton magnetic resonance spectroscopy. Further, brain was assessed histologically for growth, gross morphology, glial and neuronal development and extent of myelination. Localized proton magnetic resonance spectroscopy ((1)H MRS) showed in the BPA-exposed rat a significant increase in glutamate concentration in the hippocampus as well as in the Glu/Asp ratio. Interestingly these two metabolites are metabolically linked together in the malate-aspartate metabolic shuttle. Quantitative histological analysis revealed that the density of NeuN-positive neurons in the hippocampus was decreased in the BPA-treated offspring when compared to controls. Conversely, the density of GFAP-positive astrocytes in the cingulum was increased in BPA-treated offspring. In conclusion, exposure to low-dose BPA during gestation and lactation leads to significant changes in the Glu/Asp ratio in the hippocampus, which may reflect impaired mitochondrial function and also result in neuronal and glial developmental alterations.

How safe is bisphenol A? Fundamentals of toxicity: metabolism, electron transfer and oxidative stress

The FDA recently announced concern about the safety of bisphenol A (BPA) and the need for more research. In the current controversy, scant attention is being paid to toxicity at the fundamental, molecular level, which is the topic of this report. Important information is provided by extensive studies on metabolism. The principal pathway is detoxification, mainly by conjugation leading to a glucuronide. A minor route entails oxidation by hydroxylation to a catechol followed by further transformation to an o-quinone. The catechol-o-quinone couple is capable of redox cycling with generation of reactive oxygen species (ROS) and oxidative stress (OS). o-Quinones are highly electron affinic with very favorable reduction potentials that permit electron transfer (ET) under physiological conditions. Only small amounts are sufficient to generate large quantities of ROS catalytically. There is extensive evidence for production of ROS, which buttresses ET by o-quinone as a plausible source. In addition, there are numerous reports on toxicity to body constituents by BPA. Those adversely affected include the liver, DNA, genes, CNS, reproductive system and kidney. Since a plethora of prior studies links ROS-OS with toxicity, it is reasonable to propose a similar connection for BPA. Cell signaling also plays a role. There are various other factors involved with toxic responses, including age, with the fetus and infants being the most vulnerable. A report concludes that human exposure to BPA is not negligible. The present overview represents a novel, integrated approach to BPA toxicity. A similar article was recently published in this journal which deals with toxicity of prevalent phthalate plasticizers.

Changes in brain monoamine levels in neonatal rats exposed to bisphenol A at low doses

To examine whether exposure to bisphenol A (BPA) at low levels affect brain function, monoamine concentrations in hippocampus, striatum and brain stem, were investigated in neonatal male rats injected intracranially with BPA at 0-10microgkg(-1). Significant increases of serotonin (5-HT) in hippocampus, 5-HIAA and 5-HIAA/5-HT in brain stem, dopamine (DA) and DOPAC in striatum were observed at 28d after the injection on postnatal day 2. At 7d after the injection, increases in 5-HT and norepinephrine (NE) and decreases in DOPAC and 5-HIAA were observed in hippocampus. To investigate the degradation of BPA in brain, we also measured BPA concentrations of whole neonatal rat brain. Free BPA disappeared from brain tissues within 5h, even when the highest dose (1000microgkg(-1)) was injected. The present results suggest that BPA exposure at lower doses than environmentally relevant levels may have a great impact on monoamine levels in neonatal brain over 28d after its disappearance.

Vitamin C and resveratrol supplementation to rat dams treated with di(2-ethylhexyl)phthalate: impact on reproductive and oxidative stress end points in male offspring

This study was carried out to assess the influence of di(2-ethylhexyl)phthalate (DEHP) alone or associated with antioxidants on the male reproductive system in newborn rats, emphasizing the implications of oxidative stress and hormonal balance during prenatal and early postnatal periods. Wistar females were exposed by oral route to DEHP alone or associated with antioxidants from gestational day 7 to lactational day 2 according to the following treatment regimens: (C) vehicle control (canola oil + 1% Tween-80); (V) vitamin C (200 mg/kg) + canola oil; (R) resveratrol (10 mg/kg) + canola oil; (D) DEHP (500 mg/kg) + 1% Tween-80; (DV) DEHP (500 mg/kg) + vitamin C (200 mg/kg); and (DR) DEHP (500 mg/kg) + resveratrol (10 mg/kg). Two male pups per litter were randomly selected and necropsied on postnatal day 2. The brain and liver were removed and weighed and anogenital distance (AGD) was measured. Additionally, the testes were removed for assessment of intratesticular testosterone levels and histopathology; the liver was used to measure biomarkers of oxidative stress. Vitamin C and resveratrol alone did not affect the reproductive end points and did not induce oxidative stress. Exposure of dams to DEHP alone and associated with antioxidants resulted in hepatomegaly in offspring and significantly increased the incidence of multinucleated gonocytes in seminiferous cords. Testosterone and AGD presented a trend to decrease in DEHP-exposed groups. Catalase activity increased only in groups exposed to DEHP associated with antioxidants, although GST (gluthatione-S-transferase) activity decreased in all DEHP-exposed groups. The levels of hydroperoxides increased only in group exposed to DEHP associated with vitamin C. These results indicate that the association of DEHP with antioxidants was unable to ameliorate DEHP-induced reproductive changes, and the coadministration of DEHP and these antioxidants might even contribute to an overall increase in oxidative stress.