Effect of combined exposure to lead and ethanol on some biochemical indices in the rat

Freshwater pollution: cardiotoxicity effect of perfluorooctane sulfonic acid and neonicotinoid imidacloprid mixture

Perfluorooctanesulfonate (PFOS) is a widely used chemical that accumulates in living things and the environment, especially the aquatic, over time. It is also known as a "forever chemical". Furthermore, different anthropogenic substances are rarely found individually in the environment. Some of these substances are very toxic to aquatic species, such as imidacloprid (IMI), an insecticide belonging to the neonicotinoid family. The main objectives of this study were to investigate the effect of coexposure of these two contaminants at individual nontoxic concentration. In this study, we first analyzed different nominal concentrations of PFOS (from 0.1 to 10 μM) and IMI (from 75 to 1,000 μM) to highlight the morphological effects at 96 hr postfertilization and subsequently assessed the toxicity of mixture coexposure at both lethal and sublethal levels. Coexposure of PFOS and IMI at two individually nontoxic concentrations resulted in increased toxicity in terms of morphological alterations, accompanied by increased cell death in the pericardium. Molecular investigations confirmed the increased cardiotoxicity accompanied by cell death, showing overexpression of apoptosis-associated genes (caspase 3, bax, and bcl-2.) and a dysregulation of oxidative stress-related genes (cat, sod1, and gstp2). These results suggest that IMI could potentiate PFOS cardiotoxicity on zebrafish embryo development by alteration of antioxidative balance and induced apoptosis.

Lead contamination of fruit spirits intended for own consumption as a potential overlooked public health issue? A pilot study

OBJECTIVE

The aim of the study was to analyse the occurrence of lead in selected samples of fruit distilled spirits for own consumptions in terms of possible contribution to the occurrence of alcohol-attributable diseases.

METHODS

In a pilot study, we analysed 18 samples of fruit spirits for own consumption. Most of the samples were distilled in the local growing distilleries in the Žilina Region with exception of 3 samples collected in the Trnava Region (one of them was of Hungarian origin). Sample preparation included previous mineralization with use of microwave decomposition system Multiwave 60 50 Hz. The samples were analysed by atomic absorption spectroscopy with graphic furnace (AAS GBC XplorAA 5000 with GF 5000).

RESULTS

The average ethanol level in our samples was higher in comparison with distributed spirits. We detected lead in all samples. In two of them the concentration was lower than the limit of quantitation (LOQ). The highest lead concentrations were observed in plum spirit from Hungary (581.0 μg/l), and in grape spirit made in the Trnava Region (466.3 μg/l).

CONCLUSIONS

Lead is a widespread contaminant of fruit spirits prepared for own consumption. Taking into consideration its common occurrence and possible multiplicative effect with ethanol, we can assume that lead can contribute to the occurrence of several alcohol-attributable chronic diseases. Due to the insufficient information in this field, our results provide significant insight into the issue and present an important starting point for further research.

Rutin ameliorates oxidative stress and preserves hepatic and renal functions following exposure to cadmium and ethanol

CONTEXT

Rutin (RUT) is an antioxidant flavonoid with well-known metal chelating potentials.

OBJECTIVE

This study was designed to evaluate the protective effects of RUT against cadmium (Cd) + ethanol (EtOH)-induced hepatic and renal toxicity in rats.

MATERIALS AND METHODS

Wistar rats were treated with Cd (50 mg/kg) alone or in combination with EtOH (5 mg/kg) and RUT (25, 50 and 100 mg/kg) for 15 days. After treatment, the liver, kidney and serum were removed for biochemical assays by spectrophotometric methods.

RESULTS

Serum, hepatic and renal malondialdehyde (MDA) levels were highest in the Cd + EtOH group and lowest in Cd + EtOH animals co-treated with the highest dose of RUT (2.98 ± 0.34, 10.08 ± 2.32, 4.99 ± 1.21 vs. 1.69 ± 0.33, 6.13 ± 0.28, 3.66 ± 1.12 μmol MDA/mg protein, respectively). The serum level of Cd was increased in the Cd + EtOH treated animals compared to Cd + EtOH animals co-treated with 100 mg/kg RUT (2.54 ± 0.08 vs. 1.28 ± 0.04 ppm). Furthermore, RUT at the highest dose protected against Cd + EtOH-induced elevation of bilirubin and uric acid levels as well as activities of lactate dehydrogenase and γ-glutamyl transferase (62.86 ± 2.74 vs. 122.52 ± 6.35 µmol/L; 1.77 ± 0.35 vs. 3.23 ± 0.55 mmol/L; 9.56 ± 1.22 vs. 16.21 ± 1.64 U/L; 288.92 ± 40.12 vs. 159.8 ± 18.01 U/L). The histo-pathological changes in the liver and kidney were also reduced in the Cd + EtOH animals co-treated with RUT in a dose-dependent manner.

DISCUSSION AND CONCLUSION

RUT protected against the combined effects of Cd + EtOH on hepatic and renal functions and improved the antioxidant defence system in the blood.

Modulation of Ethanol-Metabolizing Enzymes by Developmental Lead Exposure: Effects in Voluntary Ethanol Consumption

This review article provides evidence of the impact of the environmental contaminant lead (Pb) on the pattern of the motivational effects of ethanol (EtOH). To find a mechanism that explains this interaction, the focus of this review article is on central EtOH metabolism and the participating enzymes, as key factors in the modulation of brain acetaldehyde (ACD) accumulation and resulting effect on EtOH intake. Catalase (CAT) seems a good candidate for the shared mechanism between Pb and EtOH due to both its antioxidant and its brain EtOH-metabolizing properties. CAT overactivation was reported to increase EtOH consumption, while CAT blockade reduced it, and both scenarios were modified by Pb exposure, probably as the result of elevated brain and blood CAT activity. Likewise, the motivational effects of EtOH were enhanced when brain ACD metabolism was prevented by ALDH2 inhibition, even in the Pb animals that evidenced reduced brain ALDH2 activity after chronic EtOH intake. Overall, these results suggest that brain EtOH metabolizing enzymes are modulated by Pb exposure with resultant central ACD accumulation and a prevalence of the reinforcing effects of the metabolite in brain against the aversive peripheral ACD accumulation. They also support the idea that early exposure to an environmental contaminant, even at low doses, predisposes at a later age to differential reactivity to challenging events, increasing, in this case, vulnerability to acquiring addictive behaviors, including excessive EtOH intake.

Maternal administration of melatonin prevents spatial learning and memory deficits induced by developmental ethanol and lead co-exposure

Melatonin is a radical scavenger with the ability to remove reactive oxidant species. There is report that co-exposure to lead and ethanol during developmental stages induces learning and memory deficits and oxidative stress. Here, we studied the effect of melatonin, with strong antioxidant properties, on memory deficits induced by lead and ethanol co-exposure and oxidative stress in hippocampus. Pregnant rats in lead and ethanol co-exposure group received lead acetate of 0.2% in distilled drinking water and ethanol (4g/kg) by oral gavages once daily from the 5th day of gestation until weaning. Rats received 10mg/kg melatonin by oral gavages. On postnatal days (PD) 30, rats trained with six trials per day for 6 consecutive days in the water maze. On day 37, a probe test was done and oxidative stress markers in the hippocampus were evaluated. Results demonstrated lead and ethanol co-exposed rats exhibited higher escape latency during training trials and reduced time spent in target quadrant, higher escape location latency in probe trial test and had significantly higher malondialdehyde (MDA) levels, significantly lower superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) activities in the hippocampus. Melatonin treatment could improve memory deficits, antioxidants activity and reduced MDA levels in the hippocampus. We conclude, co-exposure to lead and ethanol impair memory and melatonin can prevent from it by oxidative stress modulation.

Rutin, an antioxidant flavonoid, induces glutathione and glutathione peroxidase activities to protect against ethanol effects in cadmium-induced oxidative stress in the testis of adult rats

Exposure to cadmium (Cd) reduces sperm quality and induces oxidative stress in the testis. Rutin is an effective antioxidant flavonoid. We studied the effect of ethanol (EtOH, 5 g/kg b.wt.) intake on Cd (50 mg/kg b.wt.)-induced testicular toxicity with or without RUT pre-treatment (25, 50, 100 mg/kg b.wt.) in rats. At the end of the 15-day oral treatment, co-treatment with EtOH decreased the activities of glutathione (GSH), GSH-peroxidase and superoxide dismutase resulting to slight increase in the testicular MDA level compared to Cd-treated rats. The Cd+EtOH animals had higher levels of abnormal spermatozoa, decreased epididymal sperm number and serum testosterone levels (p < .05) compared to the Cd-treated animals. Rutin co-administration protected against the EtOH effects in a dose-dependent manner, with the Cd+EtOH+50 mg/kg RUT- and Cd+EtOH+100 mg/kg RUT-treated animals having higher GSH and GSH-Px activities beyond the control values (p < .05). In a supplementary study, animals treated daily with RUT alone (25, 50, 100 mg/kg b.wt.) for 15 days dose-dependently increased testicular GSH-peroxidase and GSH activities by 9.38%, 31.25%, 56.25% and 7.14%, 32.14%, 60.71%, respectively, compared to control values. Therefore, RUT induces GSH and GSH-Px activities to protect against Cd+EtOH-induced testis oxidative stress in rats.

The combined effects of developmental lead and ethanol exposure on hippocampus dependent spatial learning and memory in rats: Role of oxidative stress

Either developmental lead or ethanol exposure can impair learning and memory via induction of oxidative stress, which results in neuronal damage. we examined the effect of combined exposure with lead and ethanol on spatial learning and memory in offspring and oxidative stress in hippocampus. Rats were exposed to lead (0.2% in drinking water) or ethanol (4 g/kg) either individually or in combination in 5th day gestation through weaning. On postnatal days (PD) 30, rats were trained with six trials per day for 6 consecutive days in the water maze. On day 37, a probe test was done. Also, oxidative stress markers in the hippocampus were also evaluated. Results demonstrated that lead + ethanol co-exposed rats exhibited higher escape latency during training trials and reduced time spent in target quadrant, higher escape location latency and average proximity in probe trial test. There was significant decrease in superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) activities and increase of malondialdehyde (MDA) levels in hippocampus of animals co-exposed to lead and ethanol compared with their individual exposures. We suggest that maternal consumption of ethanol during lead exposure has pronounced detrimental effects on memory, which may be mediated by oxidative stress.

Lead and ethanol co-exposure lead to blood oxidative stress and subsequent neuronal apoptosis in rats

AIMS

The present study was aimed at investigating chronic exposure to lead and ethanol, individually and in combination with blood oxidative stress leading to possible brain apoptosis in rats.

METHODS

Rats were exposed to lead (0.1% w/v in drinking water) or ethanol (1 and 10%) either individually or in combination for four months. Biochemical variables indicative of oxidative stress (blood and brain) and brain apoptosis were examined. Native polyacrylamide agarose gel electrophoresis was carried out in brain homogenates for glucose-6-phosphate dehydrogenase (G6PD) analysis, whereas western blot analysis was done for the determination of apoptotic markers like Bax, Bcl-2, caspase-3, cytochrome c and p53.

RESULTS

The results suggest that most pronounced increase in oxidative stress in red blood cells and brain of animals co-exposed to lead and 10% ethanol compared all the other groups. Decrease in G6PD activity followed the same trend. Upregulation of Bax, cytochrome c, caspase-3, p53 and down-regulation of Bcl-2 suggested apoptosis in the rat brain co-exposed to lead and ethanol (10%) compared with their individual exposures. Significantly high lead accumulation in blood and brain during co-exposure further support synergistic toxicity.

CONCLUSION

The present study thus suggests that higher consumption of ethanol during lead exposure may lead to brain apoptosis, which may be mediated through oxidative stress.

Garlic Oil and Vitamin E Prevent the Adverse Effects of Lead Acetate and Ethanol Separately as well as in Combination in the Drinking Water of Rats

Daily feeding of drinking water containing lead acetate (160 mg/l) or 10% alcohol by volume or a combination of both to rats for a month produced certain deleterious effects through oxidative stress. Both heavy metal lead and alcohol are capable of doing such damages. The deleterious alterations observed were in the parameters of blood, serum and tissues, viz; Hb, Pb, proteins, lipids, lipid per oxidation, Vitamins C and E levels and enzyme activities of AST, ALT, and catalase. Simultaneous feeding of either of the two antioxidants garlic oil (GO) and vitamin E at equal doses of 100 mg/kg/day, to the rats counteracted the deleterious effects of the above two chemicals significantly. The maximum damage was brought about by feeding of drinking water containing both lead acetate and alcohol. The protective effects of GO and Vitamin E were not significantly different. The mechanism of actions of the Vitamin E and GO is probably due to their efficiency as detoxifying agents and antioxidants, to scavenging free radicals as well as an independent action of GO on the removal of lead salt as lead sulfide.

Combinational chelation therapy abrogates lead-induced neurodegeneration in rats

Lead, a ubiquitous and potent neurotoxicant causes oxidative stress which leads to numerous neurobehavioral and physiological alterations. The ability of lead to bind sulfhydryl groups or compete with calcium could be one of the reasons for its debilitating effects. In the present study, we addressed: i) if chelation therapy could circumvent the altered oxidative stress and prevent neuronal apoptosis in chronic lead-intoxicated rats, ii) whether chelation therapy could reverse biochemical and behavioral changes, and iii) if mono or combinational therapy with captopril (an antioxidant) and thiol chelating agents (DMSA/MiADMSA) is more effective than individual thiol chelator in lead-exposed rats. Results indicated that lead caused a significant increase in reactive oxygen species, nitric oxide, and intracellular free calcium levels along with altered behavioral abnormalities in locomotor activity, exploratory behavior, learning, and memory that were supported by changes in neurotransmitter levels. A fall in membrane potential, release of cytochrome c, and DNA damage indicated mitochondrial-dependent apoptosis. Most of these alterations showed significant recovery following combined therapy with captopril with MiADMSA and to a smaller extend with captopril+DMSA over monotherapy with these chelators. It could be concluded from our present results that co-administration of a potent antioxidant (like captopril) might be a better treatment protocol than monotherapy to counter lead-induced oxidative stress. The major highlight of the work is an interesting experimental evidence of the efficacy of combinational therapy using an antioxidant with a thiol chelator in reversing neurological dystrophy caused due to chronic lead exposure in rats.

Metabolic basis of ethanol-induced cytotoxicity in recombinant HepG2 cells: role of nonoxidative metabolism

Chronic alcohol abuse, a major health problem, causes liver and pancreatic diseases and is known to impair hepatic alcohol dehydrogenase (ADH). Hepatic ADH-catalyzed oxidation of ethanol is a major pathway for the ethanol disposition in the body. Hepatic microsomal cytochrome P450 (CYP2E1), induced in chronic alcohol abuse, is also reported to oxidize ethanol. However, impaired hepatic ADH activity in a rat model is known to facilitate a nonoxidative metabolism resulting in formation of nonoxidative metabolites of ethanol such as fatty acid ethyl esters (FAEEs) via a nonoxidative pathway catalyzed by FAEE synthase. Therefore, the metabolic basis of ethanol-induced cytotoxicity was determined in HepG2 cells and recombinant HepG2 cells transfected with ADH (VA-13), CYP2E1 (E47) or ADH + CYP2E1 (VL-17A). Western blot analysis shows ADH deficiency in HepG2 and E47 cells, compared to ADH-overexpressed VA-13 and VL-17A cells. Attached HepG2 cells and the recombinant cells were incubated with ethanol, and nonoxidative metabolism of ethanol was determined by measuring the formation of FAEEs. Significantly higher levels of FAEEs were synthesized in HepG2 and E47 cells than in VA-13 and VL-17A cells at all concentrations of ethanol (100-800 mg%) incubated for 6 h (optimal time for the synthesis of FAEEs) in cell culture. These results suggest that ADH-catalyzed oxidative metabolism of ethanol is the major mechanism of its disposition, regardless of CYP2E1 overexpression. On the other hand, diminished ADH activity facilitates nonoxidative metabolism of ethanol to FAEEs as found in E47 cells, regardless of CYP2E1 overexpression. Therefore, CYP2E1-mediated oxidation of ethanol could be a minor mechanism of ethanol disposition. Further studies conducted only in HepG2 and VA-13 cells showed lower ethanol disposition and ATP concentration and higher accumulation of neutral lipids and cytotoxicity (apoptosis) in HepG2 cells than in VA-13 cells. The apoptosis observed in HepG2 vs. VA-13 cells incubated with ethanol appears to be mediated by release of mitochondrial cytochrome c via activation of caspase-9 and caspase-3. These results strongly support our hypothesis that diminished hepatic ADH activity facilitates nonoxidative metabolism of ethanol and the products of ethanol nonoxidative metabolism cause apoptosis in HepG2 cells via intrinsic pathway.

Involvement of some low-molecular thiols in the peroxidative mechanisms of lead and ethanol action on rat liver and kidney

The involvement of low-molecular thiols, such as reduced glutathione (GSH) and metallothionein (Mt), in the mechanisms of the peroxidative action of lead (Pb) and ethanol (EtOH) in liver and kidney was investigated on rats treated with 500 mg Pb/l (in drinking water) and 5 g EtOH/kg body wt./24h (p.o.), alone and in conjunction with each other for 12 weeks. Beside of GSH and Mt, concentration of total and non-protein SH groups (TSH and NPSH, respectively) in these organs as well as the blood activity of dehydratase of delta-aminolevulinic acid (delta-ALAD) and the urinary concentration of delta-aminolevulinic acid (delta-ALA) were determined. The exposure to Pb and EtOH alone and in conjunction with each other led to a decrease in the blood delta-ALAD activity and an increase in the urinary delta-ALA concentration, and these effects were more markedly advanced at co-exposure. In the liver and kidney of rats treated with Pb and/or EtOH, a decrease in concentrations of GSH and NPSH was noted, compared to control. However, in the Pb+EtOH group, only the liver concentrations of NPSH and GSH were lower also compared to the Pb and EtOH groups. The liver concentration of TSH decreased in the rats exposed to EtOH alone and in conjunction with Pb, whereas the kidney concentration of TSH decreased only at co-exposure to Pb and EtOH. Mt concentration was unchanged except for an increase in the liver in the Pb and Pb+EtOH groups. Two-way analysis of variance (ANOVA/MANOVA) revealed that the changes noted at the co-exposure to Pb and EtOH resulted from an independent action of the two xenobiotics as well as from their interactive action. Negative correlations noted between the liver and kidney concentrations of GSH and/or NPSH and recently reported malondialdehyde (MDA, an indicator of lipid peroxidation) concentration in both organs of those rats indicate the relationship between the content of SH groups and the intensity of the Pb and/or EtOH-induced lipid peroxidation. The results allow for the conclusion that the decrease in the liver and kidney concentrations of GSH and NPSH are involved in the mechanisms of the peroxidative action of Pb and EtOH alone and at co-exposure in these organs.

Acute and subchronic effects of lead on the central and peripheral nervous systems in rats in combination with alcohol

Humans are exposed, either simultaneously or sequentially, to various chemicals, including the neurotoxicants lead and ethanol. The aim of the present work was to investigate the changes in the spontaneous cortical activity (electrocorticogram; ECoG) and in the stimulus-dependent evoked potentials (EPs) recorded from rats pre-treated with alcohol and treated with lead acutely (intraperitoneally) or subchronically (by gavage). The measured parameters were spectral composition of the ECoG, amplitude and the latency of the stimulus-evoked cortical potential, as well as compound action potential amplitude, conduction velocity, and relative and absolute refractory period in a peripheral nerve. With subchronic lead and alcohol treatment, significant increase in the frequency of spontaneous activity and slight decrease in the EP amplitude were seen. In acute administration, EP amplitude increased and conduction velocity of the tail nerve decreased significantly. Our results showed that, in a combined exposure situation which is likely to happen also in humans, the known effects of neurotoxic heavy metals can be more severe.

Effects of dietary lead and/or dimercaptosuccinic acid exposure on regional serotonin and serotonin metabolite content in rainbow trout (Oncorhynchus mykiss)

The lead (Pb) chelator, meso-2,3-dimercaptosuccinic acid (DMSA) may be effective in reversing some of the adverse effects of Pb exposure. Pb-induced behavioral deficits observed in fish are due to disruptions in the integrative functioning of the medulla, cerebellum, and optic tectum. Pb exposure increased serotonin (5-HT) content in all three brain regions without an effect on 5-hydroxy-3-indoleacetic acid (5-HIAA). Pb exposure followed by no Pb in the diet increased 5-HT and 5-HIAA content in all three brain regions. The replacement of dietary Pb with DMSA had no effect on 5-HT and increased 5-HIAA content. DMSA increased 5-HIAA content in all three brain regions and increased 5-HT content only the optic tectum. Treatment with DMSA may be more effective than removal of Pb from the diet in reversing Pb-induced alterations in 5-HT.

Lead and ethanol coexposure: implications on the dopaminergic system and associated behavioral functions

The present investigation involves ethanol's effects on the lead-induced alterations in the dopaminergic system. Ethanol, at a dose of 3 g/kg body weight for 8 weeks, resulted in a marked increase in the accumulation of lead in the blood and brain of animals receiving 50 mg lead/kg body weight. Levels of dopamine were found to decrease significantly, and were accompanied with increased norepinephrine levels in lead and ethanol coexposed animals. Uptake of tyrosine as well as the activities of tyrosine hydroxylase and monoamine oxidase were seen to increase significantly in lead as well as ethanol-treated animals, and these were increased to a greater extent when animals were administered lead and ethanol simultaneously. Dopamine receptor binding studies revealed a significant elevation in the number of binding sites in lead and ethanol-coexposed animals. The altered dopaminergic functions were reflected by the neurobehavioral deficits in terms of motor incoordination, aggressiveness, and hyperactivity of animals exposed to lead, the effect being more pronounced in lead- and ethanol-coexposed animals. In brief, results of this study suggests that ethanol potentiates lead-induced cellular damage at the neurochemical and neurobehavioral level.

Influence of ethanol on lead distribution and biochemical changes in rats exposed to lead

In the present study, an attempt has been made to investigate the effect of ethanol consumption on the distribution of lead in different regions of brain and body organs of male albino rats. Lead when administered intragastrically, for a period of eight weeks resulted in almost uniform accumulation of this metal in all the regions of brain, which increased by almost two fold when ethanol was given along with lead. Lead was also seen to compartmentalise in almost all the tissues of the body to varying extents, with the highest accumulation in the kidney. A progressive and appreciable accumulation of lead was seen in blood with a concomitant increase in ZPP levels in animals during the course of treatment, which increased further when ethanol was administered along with lead. The activity of delta-ALAD and AChE in blood was significantly decreased in lead as well as ethanol treated animals. However, in animals coexposed to lead and ethanol, the inhibition of delta-ALAD was not significantly different, when compared to only lead-treated animals. The results suggested that animals exposed to ethanol and lead simultaneously accumulate higher levels of lead in blood and brain of animals making them more vulnerable to the haematological and neurological toxic effects of lead.

Changes in neurotransmitter receptors and neurobehavioral variables in rats co-exposed to lead and ethanol

The influence of lead (10 mg/kg) and ethanol (10% v/v, in drinking water) administration, either alone or in combination for 8 weeks was investigated on the uptake of lead in tissues, dopamine, benzodiazepine and cholinergic (muscarinic) receptors, motor activity, number of fighting episodes and several selected lead-sensitive biochemical indices in young rats. Lead or ethanol treatment did not elicit any appreciable influence on body weight gain, tissue weight, and food intake. However, a decreased amount of mean water intake was noticed in animals ingesting ethanol plus lead. Both lead and ethanol when administered individually exacerbate the decrease of blood delta-aminolevulinic acid dehydratase (ALAD) activity while lead and ethanol administered together exhibited a pronounced inhibition of ALAD activity. A significant increase in hepatic GSH levels, hepatic and brain MDA levels was also observed in animals co-exposed to lead and ethanol compared to lead alone treated rats. Simultaneous exposure to lead and ethanol also resulted in a significantly more pronounced decrease in binding of [3H]fluintrazepam in membranes prepared from the fronto-cortical region compared to the corresponding controls. The binding of [3H]spiroperidol to striatal and [3H]quinuclidinyl benzylate (QNB) to cerebellar membranes remained unaltered in all the exposed animals. Spontaneous locomotor activity and aggressive behaviour increased significantly in the group treated with both lead and ethanol compared to the control group. The lead concentrations in blood, liver, kidney and brain were significantly higher in rats exposed simultaneously to lead and ethanol compared to lead alone exposed group. The results indicate more pronounced neurotoxic and neurobehavioural changes in animals co-exposed to lead and ethanol; however, the exact mechanism or site of its action is still not clear.

Effects of chronic lead administration on ethanol-induced locomotor and brain catalase activity

Several reports have demonstrated that chronic lead administration decreases brain catalase activity in animals. Other reports have shown a role of brain catalase on ethanol-induced behaviors. In the present study, we questioned whether mice treated chronically with lead, and therefore functionally devoid of brain catalase activity, exhibit some alterations in ethanol-induced behaviors. Swiss-Webster mice were exposed to drinking fluid containing either 500 ppm lead acetate or sodium acetate (control group) for 0, 15, 30, or 60 days before an acute ethanol administration. Following ethanol injection (2.5 g/kg, i.p.), animals were placed in open field chambers and locomotor activity was measured. Lead exposure had no effect on spontaneous locomotor activity. However, a reduction in ethanol-induced locomotor activity was found at all periods of lead exposure. After 60 days of treatment, the lead group demonstrated 35% less activity than the control group. Brain catalase activity was significantly reduced in the lead group following 60 days of exposure. This reduction in ethanol-induced locomotor activity and in brain catalase activity persisted after 40 days of lead withdrawal. The fact that brain catalase and ethanol-induced locomotor activity followed a similar pattern could suggest a relationship between both lead acetate effects and also a role for brain catalase in ethanol-induced behaviors.

Ethanol potentiates lead-induced inhibition of rat brain antioxidant defense systems

We investigated the effect of alcohol (3 g/kg body weight intragastrically) on lead-induced (50 mg/kg body weight intragastrically) oxidative stress in adult rat brain. Ethanol was found to potentiate the accumulation of lead in the rat brain by 100%. Lead and ethanol in combination also enhanced lipid peroxidation, a deteriorative process of biomembranes, and markedly decreased the antioxidant capacity of neuronal cells in terms of reduced activities of antioxidant enzymes i.e., superoxide dismutase, catalase and glutathione peroxidase. Further, the activity of glutathione reductase was also significantly decreased in lead and ethanol co-exposed animals as compared to only lead-treated animals, which had altered glutathione status. The results of the present study show that ethanol makes the adult rat brain more susceptible to the neurotoxic effects of lead by accentuating the oxidative stress induced by lead.

Beneficial effects of S-adenosyl-L-methionine on aminolevulinic acid dehydratase, glutathione, and lipid peroxidation during acute lead-ethanol administration in mice

Beneficial effects of S-adenosyl-L-methionine (SAM) in preventing inhibition of blood delta-aminolevulinic acid dehydratase (ALAD), alterations in blood and hepatic glutathione (GSH), hepatic and brain malondialdehyde (MDA) formation, and uptake of lead following acute lead plus ethanol coexposure were investigated in mice. Whereas exposure to both lead or ethanol individually produced a significant inhibition of blood delta-aminolevulinic acid dehydratase (ALAD) activity, ethanol administration alone produced only a marginal depletion of hepatic glutathione (GSH). A significant elevation of hepatic MDA concentration was observed following lead or ethanol ingestion. An appreciable increase in brain GSH following ethanol administration whereas a moderate elevation in MDA level following lead plus ethanol administration was observed. Combined lead plus ethanol exposure produced a more pronounced depletion of blood ALAD activity and an increase in hepatic MDA level compared to lead- or ethanol-alone administration. Brain GSH concentration showed an increase compared to untreated control animals or lead-alone-exposed mice. Concomitant administration of SAM partially reversed the inhibition of blood ALAD activity in all three exposed groups (i.e., lead, ethanol, or lead plus ethanol). Lead concentration in blood, liver, and brain was significantly reduced by SAM in lead-alone or lead plus ethanol coexposed groups. The results suggest that supplementation of SAM may have beneficial effects in preventing alterations in some biochemical variables and accumulation of lead in blood, liver, and brain during acute lead plus ethanol exposure in animals.

Nonsynergic effect of ethanol and lead on heme metabolism in rats

The heme biosynthetic pathway is a metabolic target of alcohol and lead poisoning. To analyze the interdependence of both xenobiotics on porphyrin metabolism, male Wistar rats (n=47) were divided into four groups and were fed Lieber-DeCarli semiliquid control or alcoholic diets containing or not containing lead acetate (160 mg/liter) for 8 weeks. After this period, hematocrit values and porphyrin concentration in liver and urine were similar in all groups, indicating that the goal of inducing only mild chronic intoxication was achieved. Compared with the control group, rats poisoned only with lead exhibited high levels of this metal in blood and liver, increased erythrocytic protoporphyrin, and hypoactivity of aminolevulinate dehydrase (ALA-D) in both blood and liver. Rats intoxicated only with alcohol exhibited mild hypoactivity of both hepatic and erythrocytic ALA-D, although such decreased enzymatic values did not achieve statistical significance. Rats receiving ethanol and lead simultaneously demonstrated abnormalities in heme biosynthesis similar to those in rats exposed to lead, although zinc hepatic levels decreased significantly only in animals exposed to both xenobiotics. Hepatic GSH and urinary ALA and porphyrin levels were maintained in a similar range in all groups.

Biochemical and histopathological changes in arsenic-intoxicated rats coexposed to ethanol

The effects of arsenic and ethanol interaction on blood, liver and serum biochemical indices, and arsenic concentration in soft tissues of rats were investigated to determine the influence of these substances in inducing susceptibility to arsenic poisoning. Arsenic, intraperitoneally (100 ppm, once, daily), ethanol in drinking water (10%), or the combination were administered for a period of 6 weeks. Both the chemicals had some additive effects in marginally elevating blood zinc protoporphyrin. Glutathione (GSH) concentrations of blood and liver were reduced by both arsenic and ethanol; however, there was a more pronounced depletion of hepatic GSH concentration in animals coexposed to arsenic and ethanol. Combined arsenic plus ethanol exposure led to significantly more elevated activities of serum transaminases than in animals administered arsenic or ethanol alone. Histopathological alterations in kidneys and liver occurred following arsenic exposure. Arsenic plus ethanol produced more pronounced liver lesions, whereas kidney changes were the same as with arsenic alone. The concentrations of arsenic in kidney and liver were higher in rats exposed to arsenic plus ethanol. The results suggest that animals exposed to arsenic plus ethanol are more vulnerable to arsenic toxicity.

Breast-feeding exposure of infants to cadmium, lead, and mercury: a public health viewpoint

The purpose of this report is to provide an overview of the public health implications of exposure via breast milk to cadmium, lead, and mercury for nursing infants and to provide health-based guidance. Daily intakes were calculated and compared with guidance values used for public health assessments at hazardous waste sites. Cadmium, lead, and mercury under normal conditions are found in breast milk at concentration ranges of < 1 microgram/L, 2-5 micrograms/L, and 1.4-1.7 micrograms/L, respectively. Women exposed environmentally or occupationally can have higher levels in their breast milk. Concentrations of about 5 micrograms/L (cadmium), 20 micrograms/L (lead), and 3.5 micrograms/L (mercury) appear to be adequate screening levels. Many factors affect both the distribution of cadmium, lead, and mercury in breast milk and the health consequences to an infant. It is not clear what additional impact low-level exposure via breast milk may have on an infant born with a body burden to one of these metals. There is sufficient evidence to make the case that contaminated breast milk is a source of potential risk to infants in certain populations. Prevention strategies that include behavior modification and proper nutrition should be communicated to women at risk. Identification and elimination of exposure pathways and a critical analysis of the benefits of breast feeding versus heavy metal exposure are needed on a site-specific or individual basis. Research is required to better understand the impact of low-level exposure to heavy metals via breast milk. Breastfeeding should be encouraged under most circumstances.

Influence of L-lysine and zinc administration during exposure to lead or lead and ethanol in rats

Influence of lysine and zinc administration on the lead-sensitive biochemical parameters and the accumulation of lead during exposure to lead or lead and ethanol was investigated in rats. The lead exposure inhibited blood delta-aminolevulinic acid dehydratase (ALAD) activity, increased blood zinc protoporphyrin (ZPP), urinary delta-aminolevulinic acid (ALA), serum glutamic oxalacetic transaminase (SGOT), serum glutamic pyruvic transaminase (SGPT), blood and tissue lead levels, and decreased blood and hepatic glutathione (GSH) contents. Some of these effects were enhanced on coexposure to ethanol. The simultaneous administration of lysine and zinc reduced tissue accumulation of lead and most of the lead-induced biochemical alterations irrespective of exposure to lead alone or lead and ethanol. The depletion of endogenous calcium and magnesium owing to lead or ethanol exposure was also prevented by co-administration of lysine and zinc.

Impact of lead pollution on the status of other trace metals in blood and alterations in hepatic functions

Lead pollution and its impact on the status of four other trace elements--Fe, Zn, Br, and Rb--have been studied in the whole blood samples of different population groups employing energy dispersive X-ray fluorescence technique. These population groups included normal, automobile workers and lead battery manufacturers. The maximum increase in the concentration of trace elements in the blood samples of automobile workers and battery manufacturers was observed for Pb, when compared with normal Pb-B levels. The effect of lead pollution had significantly reduced Zn levels in automobile workers. Fe-B levels in automobile workers had been found to be reduced significantly as compared to control, whereas in battery workers the reduction was not significant. The concentration of Br was greatly enhanced in the blood samples of automobile workers, whereas Rb-B levels were significantly higher in both the automobile and battery workers. Oral administration of lead acetate (100 mg/kg body wt) to experimental rats significantly decreased the activities of hepatic transaminases after 3 and 4 mo of treatment, whereas the activity of hepatic alkaline phosphatase decreased significantly after 4 mo of treatment. It is concluded from this study that higher Pb-B levels greatly influence the levels of other trace elements in human blood samples and also the activities of hepatic transaminases as well as alkaline phosphatase in experimental rats.

Lipid peroxidation and antioxidant defense enzymes in various regions of adult rat brain after co-exposure to cadmium and ethanol

Effect of cadmium (1 mg/kg body weight) and ethanol (2 g/kg body weight) exposure, alone as well as in combination, on essential trace metal homeostasis, lipid peroxidation and antioxidant defense enzymes in various regions of the adult rat brain was investigated. It was observed that cadmium when administered along with ethanol accumulated significantly in corpus striatum (3.5 fold) and cerebral cortex (3.0 fold) compared to the cadmium treated group. The ethanol induced accumulation of cadmium led to significant depletion in the levels of essential trace metals like zinc and copper in these regions of the brain. Further, cadmium or ethanol alone did not show any significant effect on lipid peroxidation and antioxidant defense enzymes in any of the regions of the adult brain but when given in combination, caused a significant increase in lipid peroxidation and markedly decreased the activities of antioxidant defense enzymes like glutathione peroxidase, superoxide dismutase and catalase particularly in corpus striatum and cerebral cortex. Structural alterations produced by increased lipid peroxidation after cadmium and ethanol co-exposure may have profound effect on the activities of membrane bound enzymes and hence may lead to functional impairment. The results of the present study imply that ethanol renders the adult brain more susceptible to the neurotoxic effects of cadmium. Corpus striatum and cerebral cortex are more vulnerable to the toxic effects of cadmium under the influence of ethanol than other regions of the brain.

Lead/ethanol interactions. I: rate-depressant effects

Adult male rats were exposed to a diet containing 500 ppm added lead as lead acetate (group lead-diet) or a control diet containing no added chemicals (group control-diet) for 61 days prior to commencing fixed-ratio 32 (FR 32) lever press training for water reinforcement. After steady state responding was achieved, all animals received serial administrations of acute doses of ethanol prior to the daily training session. Specifically, lead-diet and control-diet rats received i.p. injections of .25, .5, .75, 1.0, and 1.25 g/kg ethanol, in ascending order, alternating daily with injections of saline. The results revealed a dose-dependent rate-depressant effect, with higher doses of ethanol producing more behavioral suppression than lower doses for both groups. In addition, at the dose of 1.0 g/kg it was observed that the suppressive effects of ethanol on schedule-controlled responding were reduced among lead-treated animals relative to controls. These data are discussed in terms of lead-induced attenuation of the pharmacologic effects of ethanol.

Biochemical changes and essential metals concentration in lead-intoxicated rats pre-exposed to ethanol

The effects of chronic lead exposure on some hematopoietic and hepatic biochemical indices and urine, feces, and tissue essential metal concentration were investigated in rats pre-exposed to different doses of ethanol. Exposure to ethanol (0.5, 1.0, and 2.0 g/kg intraperitoneally, once daily) for 4 weeks produced an inhibition of blood delta-aminolevulinic acid dehydratase (ALAD) activity and a decrease in hepatic glutathione (GSH) concentration. Ethanol ingestion also produced a dose-dependent elevation of hepatic lipid peroxidation. Blood and hepatic calcium and hepatic magnesium contents decreased and urinary Ca and fecal Ca and Mg contents increased significantly following 4-week exposure to ethanol (2 g/kg). Lead administration (10 mg/kg, orally) for 4 weeks in ethanol pre-exposed (2 g/kg) animals produced a more pronounced inhibition of blood ALAD and elevation of urinary delta-aminolevulinic acid (ALA) excretion and hepatic GSH contents. Hepatic GSH contents decreased and hepatic lipid peroxidation increased significantly in rats given lead and pre-exposed to ethanol (2 g/kg). A more pronounced depletion of blood Ca and Mg and hepatic Mg was observed along with significant elevation of urinary Mg and fecal Ca excretion in animals administered lead and pre-exposed to ethanol (2 g/kg). The results suggest that nutritional deficiencies, particularly depletion of body Ca and Mg levels, play an important role in increasing susceptibility to lead intoxication in the rat.

Effect of ethanol on cadmium-induced lipid peroxidation and antioxidant enzymes in rat liver

We have investigated the effects of the intragastric administration of cadmium (10 mg/kg body weight) and ethanol (5.56 g/kg body weight) alone as well as in combination on hepatic lipid peroxidation, the antioxidant defense system, and the morphology of liver in rats. Cadmium given in combination with ethanol led to a marked increase in cadmium accumulation in liver compared to the level in rats treated only with cadmium. Further, cadmium and ethanol coexposure produced a more pronounced elevation in lipid peroxidation (L-px), which was associated with a significantly greater inhibition of antioxidant enzymes, glutathione peroxidase (GSH-px; EC 1.11.1.9), glutathione reductase (GR; EC 1.6.4.2) and superoxide dismutase (SOD; EC 1.15.1.1), than cadmium treatment alone. The levels of glutathione (GSH) and total thiols (TSH) also decreased significantly after cadmium and ethanol coexposure. On histopathological examination, it was observed that the livers of rats coexposed to cadmium and ethanol showed a marked degeneration of hepatocytes which was not seen in rats treated only with cadmium.

Combined exposure to lead and ethanol on tissue concentration of essential metals and some biochemical indices in rat

The effect of daily oral administration of ethanol (2.5, 5, or 10% in drinking water for 8 wk), lead (10 mg/kg, po, once daily for 8 wk), or their combination on tissue trace-metal concentration and hematopoietic and hepatic biochemical indices was investigated in male rats. Ethanol (10%) ingestion enhanced the hepatic lipid peroxidation and decreased the calcium and magnesium content of blood and liver. Coexposure to lead and ethanol (5 and 10%) produced a more pronounced elevation of blood zinc protoporphyrin (ZPP) and hepatic lipid peroxidation. Combined lead-ethanol exposure also lowered the concentration of blood and hepatic magnesium and calcium and increased the amount of lead in the blood, liver, and brain compared to a group treated with lead alone. The results suggest that chronic alcohol ingestion results in calcium and magnesium loss. However, coexposure to lead and ethanol could result in more serious depletion of calcium and magnesium, and this could be the cause of suspected synergism between alcohol consumption and lead poisoning.

Effects of combined exposure to aluminium and ethanol on aluminium body burden and some neuronal, hepatic and haematopoietic biochemical variables in the rat

The effects of the daily administration of aluminium (25 mg kg-1, orally), ethanol (10% v/v, in drinking water) or both to adult rats, for 6 weeks, on the amount of aluminium present in the tissues and the functioning of brain biogenic amines, hepatic and serum transaminases and some haematopoietic variables were investigated. Ethanol alone was seen to inhibit the activity of delta-aminolevulinic acid dehydratase (ALAD), while aluminium alone elevated the activity of blood ALAD. However, aluminium and ethanol combined produced a more pronounced inhibition of blood ALAD and hepatic glutamic pyruvic transaminase (GPT) than either aluminium or ethanol alone. Simultaneous exposure to aluminium and ethanol also produced a significant elevation in urinary delta-aminolevulinic acid (ALA) blood zinc protoporphyrin (ZPP), serum glutamic oxaloacetic transaminase (GOT) and brain homovanillic acid (HVA), and a depletion in brain dopamine (DA) and 5-hydroxytryptamine (5-HT) levels, when compared to rats given aluminium alone. The concentration of aluminium in the blood and liver was significantly higher in rats exposed to both aluminium and ethanol than in those exposed to aluminium alone. Thus the consumption of alcohol may increase the rat's susceptibility to certain effects of aluminium.

Low level lead inhibits the human brain cation pump

The impact of low level lead exposure on human central nervous system function is a major public health concern. This study addresses the inhibition of the cation pump enzyme Na, K-ATPase by low level lead. Human brain tissue was obtained at autopsy and frozen until use. Brain homogenates were preincubated with PbCl2 for 20 min at 0 degrees C. Inhibition of K-paranitrophenylphosphatase (pNPPase), a measure of the dephosphorylation step of Na,K-ATPase, reached steady state within 10 min. K-pNPPase activity, expressed (mean +/- SEM) as a percentage of control (45.2 +/- 2.7 nmol/mg/min), fell to 96.3 +/- 0.9% at 0.25 uM [PbCl2] to 82.0 +/- 1.6% at 2.5 uM [PbCl2] in homogenates prepared from normal brain. Similar results were obtained with homogenates prepared from brains of patients with a history of alcohol abuse and of those with other miscellaneous conditions. Since the mean blood level of lead in the United States has ranged recently from 9.2 to 16.0 ug/dl (0.44 to 0.77 uM), these results indicate that current in vivo levels of lead exposure may impair important human brain function.

Dose and time effects of combined exposure to lead and ethanol on lead body burden and some neuronal, hepatic and haematopoietic biochemical indices in the rat

Ethanol (1, 2 or 5 g kg-1) and lead (0.55 g l-1 in drinking water) were given either alone or in combination for 4 months to rats. The uptake of lead in tissues, some lead-sensitive variables, the levels of biogenic amines in different brain regions, hepatic lipid peroxidation, glycogen and blood glucose concentrations were measured. Ethanol or lead when given alone inhibited the activity of blood delta-aminolevulinic acid dehydratase (ALAD). The co-administration of 5 g kg-1 but not 1 or 2 g kg-1 ethanol significantly enhanced the lead-induced inhibition of blood delta-ALAD activity and the elevation of delta-aminolevulinic acid (ALA) excretion. Co-exposure to lead and ethanol (5 g kg-1) produced a more pronounced increase in hepatic lipid peroxidation and blood glucose level than either ethanol or lead alone. This combination also caused a significant increase in the dopamine (DA) contents of striatum, midbrain and pons medulla, norepinephrine (NE) contents in midbrain and 5-hydroxytryptamine (5-HT) contents of hypothalamus, striatum, midbrain and pons medulla over levels produced by lead alone. However, the level of NE in hypothalamus decreased upon co-administration. The uptake and retention of lead was significantly higher in blood, liver, kidney and brain in animals co-exposed to lead and 5 g kg-1 ethanol. Blood and kidney lead was also increased by 2 g kg-1 ethanol. The results suggest that prolonged and heavy consumption of alcohol may increase the toxicity of lead.