Nutritional Components Modify Metal Absorption, Toxic Response and Chelation Therapy

Abnormal Porphyrin Metabolism in Autism Spectrum Disorder and Therapeutic Implications

Autism spectrum disorder (ASD) is a mosaic of neurodevelopmental conditions composed of early-onset social interaction and communication deficits, along with repetitive and/or restricted patterns of activities, behavior, and interests. ASD affects around 1% of children worldwide, with a male predominance. Energy, porphyrin, and neurotransmitter homeostasis are the key metabolic pathways affected by heavy metal exposure, potentially implicated in the pathogenesis of ASD. Exposure to heavy metals can lead to an altered porphyrin metabolism due to enzyme inhibition by heavy metals. Heavy metal exposure, inborn genetic susceptibility, and abnormal thiol and selenol metabolism may play a significant role in the urinary porphyrin profile anomalies observed in ASD. Altered porphyrin metabolism in ASD may also be associated with, vitamin B6 deficiency, hyperoxalemia, hyperhomocysteinemia, and hypomagnesemia. The present review considers the abnormal porphyrin metabolism in ASD in relation to the potential pathogenic mechanism and discusses the possible metabolic therapies such as vitamins, minerals, cofactors, and antioxidants that need to be explored in future research. Such targeted therapeutic therapies would bring about favorable outcomes such as improvements in core and co-occurring symptoms.

Telomere dynamics and oxidative stress in Arabidopsis grown in lunar regolith simulant

NASA envisions a future where humans establish a thriving colony on the Moon by 2050. Plants will be essential for this endeavor, but little is known about their adaptation to extraterrestrial bodies. The capacity to grow plants in lunar regolith would represent a major step towards this goal by minimizing the reliance on resources transported from Earth. Recent studies reveal that Arabidopsis thaliana can germinate and grow on genuine lunar regolith as well as on lunar regolith simulant. However, plants arrest in vegetative development and activate a variety of stress response pathways, most notably the oxidative stress response. Telomeres are hotspots for oxidative damage in the genome and a marker of fitness in many organisms. Here we examine A. thaliana growth on a lunar regolith simulant and the impact of this resource on plant physiology and on telomere dynamics, telomerase enzyme activity and genome oxidation. We report that plants successfully set seed and generate a viable second plant generation if the lunar regolith simulant is pre-washed with an antioxidant cocktail. However, plants sustain a higher degree of genome oxidation and decreased biomass relative to conventional Earth soil cultivation. Moreover, telomerase activity substantially declines and telomeres shorten in plants grown in lunar regolith simulant, implying that genome integrity may not be sustainable over the long-term. Overcoming these challenges will be an important goal in ensuring success on the lunar frontier.

Assessing the impact and mechanisms of environmental pollutants (heavy metals and pesticides) on the male reproductive system: a comprehensive review

The escalation of technological advancements, coupled with the increased use of hazardous chemicals, has emerged as a significant concern for human health. Exposure to environmental pollutants like heavy metals and pesticides (insecticides, herbicides and fungicides) is known to significantly contribute to various health problems, particularly affecting reproductive health. Disturbances in reproductive potential and reproductive toxicity in males are particularly worrisome. Existing literature suggests that exposure to these environmental pollutants significantly alters male reproductive parameters. Thus, it is imperative to thoroughly analyze, comprehend, and evaluate their impact on male reproductive toxicity. Oxidative stress and disruptions in redox equilibrium are major factors through which these pollutants induce changes in sperm parameters and affect the reproductive system. Insecticides, fungicides, and herbicides act as endocrine disruptors, interfering with the secretion and function of reproductive hormones such as testosterone and luteinizing hormone (LH), consequently impacting spermatogenesis. Additionally, heavy metals are reported to bio-accumulate in reproductive organs, acting as endocrine disruptors and triggering oxidative stress. The co-operative association of these pollutants can lead to severe damage. In this comprehensive review, we have conducted an in-depth analysis of the impact of these environmental pollutants on the male reproductive system, shedding light on the underlying mechanisms of action.

Toxicity and sublethal effects of lead (Pb) intake on honey bees (Apis mellifera)

Heavy metal pollution is becoming a worldwide problem affecting pollinators. The massive use of lead (Pb), the most harmful metal for the biosphere, in industries has increased the risk for honey bees. Pb exerts toxicity on living organisms inducing mainly oxidative stress. We assessed the toxicity and sublethal effects of Pb ingestion on protein content, catalase (CAT) activity, fat content and fatty acid (FA) profile of honey bee workers (Apis mellifera L.) under different nutritional conditions during chronic exposure tests. The LD50 was 15.13 ± 6.11 μg Pb2+/bee, similar to other reports. A single oral sublethal dose of 15 μg of Pb2+ affected the survival of bees fed with sugary food for ten days after Pb ingestion while supplementing the diet with bee bread improved Pb tolerance. The highest protein content was found in bees fed with the sugar paste and bee bread diet without Pb. CAT activity tended to decrease in bees of Pb groups independently of diet. Fat content was not affected by the diet type received by bees or Pb ingestion, but the FAs profile varied according to the nutritional quality of the diet. The results highlight that a single sublethal dose of Pb negatively affected the body proteins of bees despite the nutritional condition but did not disturb the FAs profile of workers. Nutrition plays an important role in preventing Pb-induced toxicity in honey bees.

Systemic impact of heavy metals and their role in cancer development: a review

Heavy metals are well-recognised as environmental hazards due to their toxicity, environmental persistence, and bioaccumulation in living organisms. Human health is a crucial concern related to terrestrial and aquatic ecosystems poisoned by harmful heavy metals. Most heavy metals pollute the air, water, and soil, which can be fatal to humans. Humans and other species can be exposed to heavy metals through the food chain if the metals oxidise or combine with other environmental elements (such as water, soil, or air). Their entry into the food chain assures interactions with biological macromolecules in living systems, including humans, resulting in undesirable outcomes. Human poisonings have typically been caused by mercury, lead, chromium, cadmium, and arsenic. The build-up of these metals in living organisms causes various harmful consequences on different organs and tissues. The gravitas of heavy metal toxicity regarding molecular impact and carcinogenesis needs in-depth understanding despite the plethora of available data. Hence, additionally, we attempt to elaborate on the multi-level impact of five heavy metals and emphasise their role in cancer development. The rationale of this essay is thus to understand the role of five heavy metals, viz., lead (Pb), cadmium (Cd), chromium (Cr), arsenic (As), and mercury (Hg), in carcinogenesis. Heavy metals interfere with various biological functions, including proliferation, differentiation, repair of damage, and apoptosis. By comparing their modes of action, we see that these metals share common mechanisms for inducing toxicity, such as reactive oxygen species (ROS) production, antioxidant defence weakening, enzyme inactivation, and oxidative stress.

Nephroprotective Efficacy of Selenium and Zinc Against Potassium Dichromate-Induced Renal Toxicity in Pregnant Wistar Albino Rats

Hexavalent chromium (CrVI) compounds are potent toxicants commonly used in numerous industries. Thus, potential toxic effects and health hazards are of high relevance. Selenium (Se) and zinc (Zn) are known for their antioxidant and chemoprotective properties. However, little is known about their protective effects against CrVI-induced renal damage during pregnancy. In this context, the present study aimed to investigate the protective efficacy of these two essential elements against potassium dichromate-induced nephrotoxicity in pregnant Wistar Albino rats. Female rats were divided into control and four treated groups of six each receiving subcutaneously on the 3rd day of pregnancy, K₂Cr₂O₇ (10 mg/kg, s.c. single dose) alone, or in association with Se (0.3 mg/kg, s.c. single dose), ZnCl₂ (20 mg/kg, s.c. single dose) or both of them simultaneously. The nephrotoxic effects were monitored by the evaluation of plasma renal parameters, oxidative stress biomarkers, DNA damage, and renal Cr content. The obtained results showed that K₂Cr₂O₇ disturbed renal biochemical markers, induced oxidative stress and DNA fragmentation in kidney tissues, and altered renal histoarchitecture. The co-administration of Se and/or ZnCl₂ has exhibited pronounced chelative, antioxidant, and genoprotective effects against K₂Cr₂O₇-induced renal damage and attenuated partially the histopathological alterations. These results suggest that Se and Zn can be used as efficient nephroprotective agents against K₂Cr₂O₇-induced toxicity in pregnant Wistar Albino rats.

Acute Oral Administration of Cerium Oxide Nanoparticles Suppresses Lead Acetate-Induced Genotoxicity, Inflammation, and ROS Generation in Mice Renal and Cardiac Tissues

Lead, a highly toxic pollutant, causes numerous health problems and affects nearly all biological systems thus arousing interest in using antioxidants to reduce its toxic effects. Therefore, the undertaken study estimated the influence of cerium oxide nanoparticles (CeO2-NPs) on the lead acetate-induced genotoxicity and inflammation in the kidney and heart tissues of mice. Twenty male mice were randomly divided into negative control and lead acetate and/or CeO2-NPs administrated groups. Comet and diphenylamine assays were conducted to assess the DNA damage and the expression of apoptosis-related genes and inflammatory cytokines were also measured in addition to the estimation of reactive oxygen species (ROS) level. Co-administration of CeO2-NPs significantly reduced the DNA damage and ROS generation caused by lead acetate in the kidney and heart tissues. The co-administration of CeO2-NPs also ameliorated the lead acetate-induced dysregulation in the expression levels of p53, K-ras, interleukin-6, and cyclooxygenase-2 in the kidney and heart. Conclusion: the co-administration of CeO2-NPs suppresses the genotoxicity, inflammation, and ROS generation resulting from lead acetate administration and restoring the genomic DNA integrity; thus, administration of CeO2-NPs is recommended to minimize the lead acetate-induced hazards.

Sesamin: Insights into its protective effects against lead-induced learning and memory deficits in rats

BACKGROUND

Lead (Pb) is one of the most hazardous pollutants that induce a wide spectrum of neurological changes such as learning and memory deficits. Sesamin, a phytonutrient of the lignan class, exhibits anti-inflammatory, anti-apoptotic, and neuroprotective properties. The present study was designed to investigate the effects of sesamin against Pb-induced learning and memory deficits, disruption of hippocampal theta and gamma rhythms, inflammatory response, inhibition of blood δ-aminolevulinic acid dehydratase (δ-ALA-D) activity, Pb accumulation, and neuronal loss in rats.

METHODS

Sesamin treatment (30 mg/kg/day; P.O.) was started simultaneously with Pb acetate exposure (500 ppm in standard drinking water) in rats, and they continued for eight consecutive weeks.

RESULTS

The results showed that chronic exposure to Pb disrupted the learning and memory functions in both passive-avoidance and water-maze tests, which was accompanied by increase in spectral theta power and theta/gamma ratio, and a decrease in spectral gamma power in the hippocampus. Additionally, Pb exposure resulted in an enhanced tumor necrosis factor-alpha (TNF-α) content, decreased interleukin-10 (IL-10) production, inhibited blood δ-ALA-D activity, increased Pb accumulation, and neuronal loss of rats. In contrast, sesamin treatment improved all the above-mentioned Pb-induced pathological changes.

CONCLUSION

This data suggests that sesamin could improve Pb-induced learning and memory deficits, possibly through amelioration of hippocampal theta and gamma rhythms, modulation of inflammatory status, restoration of the blood δ-ALA-D activity, reduction of Pb accumulation in the blood and the brain tissues, and prevention of neuronal loss.

Modulatory efficacy of Punica granatum L. powder ethanol extract (PLEE) on lead acetate-induced hepatic and renal toxicity

Background

Pomegranate powder derived from pomegranate fruit contains phytochemicals chief of which is ellagitannins. Owing to their high antioxidative capabilities we investigated its efficacy against lead acetate induced hepatic and renal toxicity.

Methods

Pomegranate powder (500 g) was procured and soaked in 1 Litre of ethanol for three days, its filtrate was concentrated and freeze dried to form Punica granatum L. ethanol extract (PLEE). Thirty (30) male albino Wistar rats with average weight between 140 ± 20 g were used for this study. They were equally shared into 6 groups with 5 animals each; A: Control; B: Lead acetate only C: Lead acetate + PLEE (1); D: Lead acetate + PLEE (2); E: PLEE (1) and F: PLEE (2). Serum, liver and kidney samples were obtained for biochemical assays. The integrity of liver and kidney tissues were also accessed.

Results

Lead administration resulted in marked elevations in liver transaminases in serum and liver as well as a significant increase in kidney function markers in the serum and kidney (p < 0.05). There was also a significant decline in average body weight, antioxidant markers in the liver and kidney of Wistar rats while there was a significant increase in lipid peroxidation levels in both liver and kidney. However, administration of PLEE at different doses significantly modulated these changes.

Conclusion

Lead acetate administration led to hepatic and renal toxicity as evident by alterations in liver and kidney function markers, antioxidant status and tissue integrity. However, PLEE can combat these toxicities.

Ameliorative effect of ZnO-NPs against bioaggregation and systemic toxicity of lead oxide in some organs of albino rats

Lead is one of the major environmental pollutions worldwide, particularly in developing countries. Though, various occupational and public health measures have been undertaken to control lead exposure. The present study is designed to investigate the role of zinc oxide nanoparticles (ZnO-NPs) to reduce the bioaggregation of lead in the brain, liver, and kidneys and prevent these organ oxidative damage and apoptosis. Twenty male Wistar rats were grouped into 4 gatherings and exposed to the following materials daily on the skin for 2 weeks: 1-normal saline, 2-ZnO-NPs, 3-PbO, and 4-ZnO-NPs+ PbO. Topical application of PbO to rats increased lead contents in blood and different organs causing remarkable oxidative stress damage, apoptosis, and histopathological alterations in these organs. Moreover, PbO-receiving group showed strong positive caspase-3 protein expression with up-regulation of mRNA levels of BAX and COX-2. Co-treatment of ZnO-NPs with PbO could diminish the toxicologic parameters and the above-mentioned immune marker and gene expression levels. Our data suggest the role of ZnO-NPs cream to reduce the risk of lead dermal exposure via preventing absorption and accumulation of it in the internal organs so that it protects these organs from further damage.

Effect of Antioxidants on Heavy Metals Induced Conformational Alteration of Cytochrome C and Myoglobin

BACKGROUND

The exposure to heavy metals due to unrestrained industrialization, pollution and non-degradability imposes a significant risk to human health. Proteins are prime targets of heavy metal stress, however, the underlying mechanisms and its impact on heme proteins is still not entirely clear.

OBJECTIVE

To analyze the deleterious effect of heavy metals such as cadmium, chromium and mercury on conformation of two proteins namely, cytochrome c and myoglobin. The protective effect of glycine and ascorbic acid (animal origin), gallic acid and sesamol (plant origin) on heavy metal exposure was studied.

METHODS

Far- and near-UV Circular Dichroism (CD) measurements monitored the changes in secondary and tertiary structure. Absorption Soret spectroscopy study revealed changes in heme-protein interaction. Peroxidase activity has been assayed to measure the absorption of tetraguaiacol. The interaction of heme proteins with different heavy metals was done using docking study.

RESULTS

Far- and near-UV CD measurements reveal that heavy metals disrupt the secondary and tertiary structure of heme proteins. Antioxidants counteract the deleterious effect of heavy metals. Absorption spectroscopy revealed changes in the Soret region of these heme proteins. Changes in peroxidase activity was observed on addition of heavy metals and antioxidants. Molecular docking validated interaction of the heavy metals with proteins with a significant binding affinity (-2.3 kcal/- mol).

CONCLUSION

Heavy metals interfered and disrupted both the heme proteins and mercury showed the maximum deleterious effect, further, chromium showed detrimental effect at very small concentration. The antioxidants from animal origin exhibited better protective response than those from plant source.

Tight sorption of arsenic, cadmium, mercury, and lead by edible activated carbon and acid-processed montmorillonite clay

Heavy metal exposure in humans and animals commonly occurs through the consumption of metal-contaminated drinking water and food. Although many studies have focused on the remediation of metals by purification of water using sorbents, limited therapeutic sorbent strategies have been developed to minimize human and animal exposures to contaminated water and food. To address this need, a medical grade activated carbon (MAC) and an acid processed montmorillonite clay (APM) were characterized for their ability to bind heavy metals and mixtures. Results of screening and adsorption/desorption isotherms showed that binding plots for arsenic, cadmium, and mercury sorption on surfaces of MAC (and lead on APM) fit the Langmuir model. The highest binding percentage, capacity, and affinity were shown in a simulated stomach model, and the lowest percentage desorption (< 18%) was shown in a simulated intestine model. The safety and protective ability of MAC and APM were confirmed in a living organism (Hydra vulgaris) where 0.1% MAC significantly protected the hydra against As, Cd, Hg, and a mixture of metals by 30-70%. In other studies, APM showed significant reduction (75%) of Pd toxicity, compared with MAC and heat-collapsed APM, suggesting that the interlayer of APM was important for Pb sorption. This is the first report showing that edible sorbents can bind mixtures of heavy metals in a simulated gastrointestinal tract and prevent their toxicity in a living organism. Graphical abstract.

Caffeic acid protects against Aβ toxicity and prolongs lifespan in Caenorhabditis elegans models

Caffeic acid may alleviate Aβ-induced toxicity and increase lifespan by increasing signaling pathway-associated oxidative stress and regulating metabolism in C. elegans.

Moringa oleifera leaves ethanolic extract influences DNA damage signaling pathways to protect liver tissue from cobalt -triggered apoptosis in rats

This study assessed the potential of Moringa oleifera leaves ethanol extract (MLEE) in attenuating the detrimental effects of cobalt dichloride (CoCl₂) on rat liver. Forty rats were assigned to five equal groups: control group, MLEE-treated group, CoCl₂-treated group, prophylaxis co-treated group, and therapeutic co-treated group. The levels of Co, hepatic injury markers, total antioxidant capacity (TAC), and oxidative stress biomarkers (reactive oxygen species [ROS] and protein carbonyl [PC]) were evaluated. Comet assay was used to evaluate the extent of DNA damage. Further, the expression profile of DNA-damage effector genes was assayed by real-time quantitative polymerase chain reaction (qRT-PCR) analysis. Immunohistochemical analysis of heat shock protein (HSP-70) in hepatocytes was conducted. The results showed that the exposure of CoCl₂ to rats resulted in declined TAC, elevated oxidative injury, and induced DNA damage markers. Upregulation of mRNA expression of tumor suppressor protein (P53), apoptosis inducing factor (AIF), and apoptotic peptidase activating factor 1 (Apaf-1) was observed. The immunostaining density of HSP-70 expression was found to be elevated. Thus, MLEE reduced the CoCl₂-induced genotoxicity by preventing CoCl₂-induced generation of ROS, and protected against ROS mediated-oxidative injury and DNA damage. Moreover, the expression of DNA damage effector genes was affected. Based on these results, we conclude that MLEE is more effective when administered as a prophylactic regimen with the exposure to CoCl₂.

Lactobacillus plantarum LP33 attenuates Pb-induced hepatic injury in rats by reducing oxidative stress and inflammation and promoting Pb excretion

Lead (Pb) is one of the most common heavy metals and is harmful to human health. The liver is considered as a major target organ for Pb poisoning. Although probiotics have been shown to alleviate liver injury, the protective effect of Lactobacillus plantarum LP33 (LP33) against Pb-induced hepatotoxicity remains unclear. In order to explore the hepatoprotective effect of LP33, LP33 was administered to Pb-intoxicated Sprague-Dawley rats once daily by oral gavage for 8 weeks. The present results showed that LP33 supplementation alleviated liver injury, and inhibited oxidative stress and inflammation in Pb-exposed rats. Treatment with LP33 also promoted the phosphorylation of adenosine monophosphate-activated protein kinase and protein kinase B, activated nuclear factor erythroid 2-related factor 2 signaling and inhibited the activation of nuclear factor-κB signaling in liver tissues of rats exposed to Pb. Additionally, LP33 exhibited adequate Pb-binding capacity and satisfactory survival under simulated gastrointestinal conditions in vitro, and promoted Pb excretion via enterohepatic circulation of bile acids. This study demonstrated that LP33 reduced Pb-induced oxidative stress and inflammation and promoted Pb excretion, thereby attenuating the Pb-induced hepatic injury. Our findings suggest that LP33 supplementation may be a potential strategy for the treatment of Pb-induced hepatic toxicity.

Ethanolic Extract of Moringa oleifera Leaves Influences NF-κB Signaling Pathway to Restore Kidney Tissue from Cobalt-Mediated Oxidative Injury and Inflammation in Rats

This study aimed to describe the protective efficacy of Moringa oleifera ethanolic extract (MOEE) against the impact of cobalt chloride (CoCl₂) exposure on the rat’s kidney. Fifty male rats were assigned to five equal groups: a control group, a MOEE-administered group (400 mg/kg body weight (bw), daily via gastric tube), a CoCl₂-intoxicated group (300 mg/L, daily in drinking water), a protective group, and a therapeutic co-administered group that received MOEE prior to or following and concurrently with CoCl₂, respectively. The antioxidant status indices (superoxide dismutase (SOD), catalase (CAT), and reduced glutathione (GSH)), oxidative stress markers (hydrogen peroxide (H₂O₂), 8-hydroxy-2-deoxyguanosine (8-OHdG), and malondialdehyde (MDA)), and inflammatory response markers (nitric oxide (NO), tumor necrosis factor (TNF-α), myeloperoxidase (MPO), and C-reactive protein (CRP)) were evaluated. The expression profiles of pro-inflammatory cytokines (nuclear factor-kappa B (NF-kB) and interleukin-6 (IL-6)) were also measured by real-time quantitative polymerase chain reaction (qRT-PCR). The results showed that CoCl₂ exposure was associated with significant elevations of oxidative stress and inflammatory indices with reductions in the endogenous tissue antioxidants’ concentrations. Moreover, CoCl₂ enhanced the activity of the NF-κB inflammatory-signaling pathway that plays a role in the associated inflammation of the kidney. MOEE ameliorated CoCl₂-induced renal oxidative damage and inflammatory injury with the suppression of the mRNA expression pattern of pro-inflammatory cytokine-encoding genes. MOEE is more effective when it is administered with CoCl₂ exposure as a prophylactic regimen. In conclusion, MOEE administration exhibited protective effects in counteracting CoCl₂-induced renal injury in rats.

Protective role of selenium in the shortening of telomere length in newborns induced by in utero heavy metal exposure

The effects of toxic heavy metals, such as arsenic (As), cadmium (Cd), and lead (Pb), on telomere length (TL) have been reported previously. Although selenium (Se) is considered as an anti-oxidant which may detoxify the effects, there are no data on whether Se could protect against the TL-shortening effects of heavy metals. Thus, the aim of this study was to evaluate the protective role of Se against heavy metal-induced TL shortening. A birth cohort study was conducted in Myanmar in 2016, including 408 mother-infant pairs. First, pregnant women in the third trimester were interviewed concerning their socioeconomic, and pregnancy and birth characteristics using a pre-validated questionnaire. Maternal spot urine samples were collected after the interview. During the follow-up period (1-3 months), blood samples were collected from the umbilical cord at birth by local health workers. Metal concentrations were measured using inductively coupled plasma mass spectrometry (ICP-MS). TL was measured by quantitative real-time polymerase chain reaction (PCR). Relative TL was calculated as the ratio of telomere genes to single-copy genes. To evaluate the effect of Se on TL shortening, molar ratios were calculated. Linear regression analyses were performed to examine the associations between heavy metals and TL, individually and after adjustment for Se level. The effects of As, Cd, and Pb exposure on TL were smaller after adjustment for the Se level, especially for Pb (unadjusted β = -0.10; 95% CI: 0.18, -0.01; adjusted β = -0.03; 95% CI: 0.13, 0.05). On stratifying the data by Se concentration, there was no significant association between Cd or Pb exposure and TL in the high-Se group. Our study indicated a protective effect of Se against the TL shortening induced by heavy metal exposure, where the effect sizes were smaller after adjusting for the Se level, compared to individual metal exposure.

Lead Toxicity: Health Hazards, Influence on Food Chain, and Sustainable Remediation Approaches

Lead (Pb) toxicity has been a subject of interest for environmental scientists due to its toxic effect on plants, animals, and humans. An increase in several Pb related industrial activities and use of Pb containing products such as agrochemicals, oil and paint, mining, etc. can lead to Pb contamination in the environment and thereby, can enter the food chain. Being one of the most toxic heavy metals, Pb ingestion via the food chain has proven to be a potential health hazard for plants and humans. The current review aims to summarize the research updates on Pb toxicity and its effects on plants, soil, and human health. Relevant literature from the past 20 years encompassing comprehensive details on Pb toxicity has been considered with key issues such as i) Pb bioavailability in soil, ii) Pb biomagnification, and iii) Pb- remediation, which has been addressed in detail through physical, chemical, and biological lenses. In the review, among different Pb-remediation approaches, we have highlighted certain advanced approaches such as microbial assisted phytoremediation which could possibly minimize the Pb load from the resources in a sustainable manner and would be a viable option to ensure a safe food production system.

Blood lead in children and associations with trace elements and sociodemographic factors

BACKGROUND

No safe blood lead concentration in children has been identified. Lead can affect nearly every system in the body and is especially harmful to the developing central nervous system of children. The aim of this study is to analyze blood lead in a population of children and its association with sociodemographic variables, biochemical parameters, copper, iron, selenium and zinc.

METHODS

We recruited 155 children (86 boys and 69 girls) with a mean age of 7.3 (SD:4.1). Blood lead and serum selenium concentrations were measured by electrothermal atomic absorption spectrometry. Serum copper and zinc concentrations were measured by flame atomic absorption spectrometry. Serum iron levels were determined by colorimetric assay. A risk exposure questionnaire for lead was administered to the participants.

RESULTS

The median blood lead level was 1.1 (IQR 0.7-1.6) μg/dL. Regarding risk exposure factors, the youngest children (<2 years) who played outdoors presented a median blood lead concentration of 1.1 μg/dL IQR: 0.48-1.48, compared to the median of 0.3 μg/dL IQR:0.2-0.48 in the children who stated they played at home (p = 0.024). Significant differences were also found when taking into account those parents who smoked (median 1.3 IQR 0.8-1.9 μg/dL vs 0.9 IQR 0.5-1.4 μg/dL of non-smokers, p = 0.002). Children who drank tap water had higher blood lead levels (median 1.2 IQR 0.7-1.6 μg/dL) than those who drank bottled water (median 0.7 IQR 0.2-1.3 μg/dL p = 0.014). In addition, children whose mothers had not finished school had higher blood lead levels (median 1.7 IQR 1.2-2.3 μg/dL) than those whose mothers had finished school (median 1.2 IQR 0.7-1.7 μg/dL) and those whose mothers had gone to university (median 0.9 IQR 0.5-1.4 μg/dL) p = 0.034. In the multivariate lineal regression analysis we continue to observe the association between mother's higher level of education and lower blood levels (p = 0.04) and the interaction between age and outdoor play (p = 0.0145).

CONCLUSIONS

In spite of the decline in blood lead concentrations, associated risk factors continue to exist in vulnerable populations such as children.

Neuroprotective and long term potentiation improving effects of vitamin E in juvenile hypothyroid rats

Abstract. Protective effects of vitamin E (Vit E) on long term potentiation (LTP) impairment, neuronal apoptosis and increase of nitric oxide (NO) metabolites in the hippocampus of juvenile rats were examined. The rats were grouped (n=13) as: (1) control; (2) hypothyroid (Hypo) and (3) Hypo-Vit E. Propylthiouracil (PTU) was given in drinking water (0.05%) during 6 weeks. Vit E (20 mg/ kg) was daily injected (IP). To evaluate synaptic plasticity, LTP from the CA1 area of the hippocampus followed by high frequency stimulation to the ipsilateral Schafer collateral pathway was carried out. The cortical and hippocampal tissues were then removed to measure NO metabolites. The brains of 5 animals in each group were removed for apoptosis study. The hypothyroidism status decreased the slope, 10–90% slope and amplitude of field excitatory post synaptic potential (fEPSP) compared to the control group (P<0.01–P<0.001). Injection of Vit E increased the slope, 10–90% slope and amplitude of the fEPSP in the Hypo-Vit E group in comparison to the Hypo group (P<0.05–P<0.01). TUNEL positive neurons and NO metabolites were higher in the hippocampus of the Hypo rats, as compared to those in the hippocampus of the control ones (P<0.001). Treatment of the Hypo rats by Vit E decreased apoptotic neurons (P<0.01–P<0.001) and NO metabolites (P<0.001) in the hippocampus compared to the Hypo rats. The results of the present study showed that Vit E prevented the LTP impairment and neuronal apoptosis in the hippocampus of juvenile hypothyroid rats.

Environmental toxic agents: The impact of heavy metals and organochlorides on brain development

Exposure to environmental toxicants can have deleterious effects on the development of physical, cognitive, and mental health. Extensive laboratory and clinical studies have demonstrated how the developing brain is uniquely sensitive to toxic agents. This chapter focuses on the main neurologic impairments linked to prenatal and postnatal exposure to lead, methylmercury, and polychlorinated biphenyls, three legacy environmental contaminants whose neurotoxic effects have been extensively studied with respect to cognitive and behavioral development. The main cognitive, emotion regulation, sensory, and motor impairments in association with these contaminants are briefly reviewed, including the underlying neural mechanisms such as neuropathologic damages, brain neurotransmission, and endocrine system alterations. The use of neuroimaging as a novel tool to better understand how the brain is affected by exposure to environmental contaminants is also discussed.

Putative impacts of phytogenic additives to ameliorate lead toxicity in animal feed

Lead (Pb) is a toxic heavy metal and an environmental pollutant, particularly because of its anthropogenic activity. The main impacts of Pb is recognized to cause injurious influences of various levels of the tropic chain, due to bio-accumulated lead causes many health issues such as intoxication of different body organs, such as kidneys and liver, and reproductive and nervous systems. Industrial lead toxicity has reduced as a result of the attempts to decrease the lead levels in the surrounding work environment. Conversably, health risks related with long-term environmental exposure to a low dose of Pb have been steadily demonstrated. Long-term exposure to lead toxicity caused inflammatory infiltration, degenerative changes in testicular tissues, reduction in spermatocytes, necrosis of hepatocytes, degeneration in renal tubules, and renal epithelium hypertrophy. Hence, we need an influential approach to vanquish lead toxicity. This consequence has emerged the necessity for potentially safe represent remedy, favorably keeping both enhancement and chelating of the antioxidant competences. Many antioxidants have been used for chelating heavy toxic pollutants such as lead and oxidative stress released in excess during lead exposure. Several studies have stated the noticeable gathering of herbal singly or in combination in modulating lead-induced disturbances, therefore proposing great promise in enhancing health status and welfare of man as well as animals. For this, in the current review, we tried to discuss the enormous harmful influences of lead toxicity on the animal model and the disturbing truth that this detrimental toxic substance can be found quite simply in the surroundings and amplitude.

Speciation transformation of arsenic in abalone viscera hydrolysate fraction: In vitro digestion and in vivo metabolism

Speciation transformation of arsenic in the abalone viscera hydrolysate fraction (AVHF) was evaluated using in vitro and in vivo methods to determine its safety given that AVHF is rich in arsenic. The dimethylarsinic acid (DMA) proportion and some free amino acid contents increased, whereas arsenobetaine (AB) proportion decreased when AVHF was digested by pepsin. However, molecular weight distribution was unchanged, and no obvious changes were found in the intestinal medium. In the single-dose experiment, the AB concentration on the mouse plasma rapidly increased, which reached up to 12.53 ng/mL in 2 h after the administration of AVHF (10 g/kg body weight) and reduced to half of the maximum at 8 h after administration. Furthermore, alanine (Ala) content in the urine of mice increased at 8 h after AVHF administration, suggesting that Ala might be chelated with arsenic and could not be absorbed well. Long-term experiments showed that AB was not accumulated in mice tissue/organ. However, some AB could be converted into DMA, which was mainly accumulated in mice hair. The in vivo experiments also suggested that the AVHF is safe as health food.

Crocus sativus restores dopaminergic and noradrenergic damages induced by lead in Meriones shawi: A possible link with Parkinson's disease

Lead (Pb) is a metal element released into the atmosphere and a major source of environmental contamination. The accumulation and concentration of this metal in a food web may lead to the intoxication of the body, more precisely, the nervous system (NS). In addition, Pb-exposure can cause structural and functional disruption of the NS. Studies have shown that Pb-exposure could be a risk factor in the development of Parkinson's disease (PD). The latter is related to dopaminergic deficiency that may be triggered by genetic and environmental factors such as Pb intoxication. In this study, we have evaluated, in one hand, the neurotoxic effect of Pb (25 mg / kg B.W i.p) for three consecutive days on dopaminergic system and locomotor performance in Merione shawi. In the other hand, the possible restorative potential of C. sativus (CS) (50 mg / kg BW) by oral gavage. The immunohistochemical approach has revealed that Pb-intoxicated Meriones show a significant increase of Tyrosine Hydroxylase (TH) levels within the Substantia Nigra compacta (SNc), Ventral Tegmental Area (VTA), Locus Coeruleus (LC), Dorsal Striatum (DS) and Medial Forebrain Bundle (MFB), unlike the control meriones, a group intoxicated and treated with Crocus sativus hydroethanolic extract (CSHEE) and treated group by CSHEE. Treatment with CSHEE, has shown a real potential to prevent all Pb-induced damages. In fact, restores the TH levels by 92%, 90%, 88%, 90% and 93% in SNc, VTA, LC, DS and MFB respectively, similarly, locomotor activity dysfunction in Pb-intoxicaed meriones was reinstated by 90%. In this study, we have revealed a new pharmacological potential of Crocus sativus that can be used as a neuroprotective product for neurodegenerative disorders, especially, which implying dopaminergic and noradrenergic injuries, like PD, trigged by heavy metals.

Lead: Tiny but Mighty Poison

The documentation of lead toxicity (plumbism) dates back to the times when man learnt its various applications. This versatile heavy metal is non-degradable and its ability to get accumulated in the body that goes undiagnosed, makes it a serious environmental health hazard. Lead is now known to affect almost every organ/tissue of the human body. With irreversible effects on neurobiological development of young children and foetus, its toxicity has lasting implications on the human life. Outlining the symptoms, diagnosis and treatment therapy for lead poisoning, the present review elaborates the pathophysiological effects of lead on various organs. This will be of immense help to the health professionals so as to inculcate a better understanding of the lead poisoning which otherwise is asymptomatic. With chelation therapy being the classic path of treatment, new strategies are being explored as additive/adjunct therapy. It is now understood that lead toxicity is completely preventable. In this regard significant efforts are in place in the developed countries whereas much needs to be done in the developing countries. Spreading the awareness amongst the masses by educating them and reducing the usage of lead following stricter industry norms appears to be the only roadmap to prevent lead poisoning. Efforts being undertaken by the Government of India and other organisations are also mentioned.

Effect of Lead on Human Middle Ear Epithelial Cells

Lead is a ubiquitous metal in the environment, but no studies have examined lead toxicity on the middle ear. Here, we investigated lead toxicity and its mechanism in human middle ear epithelial cells (HMEECs). Moreover, we investigated the protective effects of amniotic membrane extract (AME) and chorionic membrane extract (CME) against lead toxicity in HMEECs. Cell viability was analyzed using the cell counting kit, and reactive oxygen species (ROS) activity was measured using a cellular ROS detection kit. After lead(II) acetate trihydrate treatment, mRNA levels of various genes were assessed by semiquantitative real-time polymerase chain reaction. Following treatment with AME or CME after lead exposure, the changes in cell viability, ROS activity, and gene expression were analyzed. Exposure to >100 μg/mL of lead(II) acetate trihydrate caused a significant decrease in cell viability and increased ROS production in HMEECs. Lead exposure significantly increased the mRNA expression of genes encoding inflammatory cytokines and mucins. Administration of AME or CME restored cell viability, reduced ROS activity, and ameliorated mRNA levels. Our findings suggest that environmental lead exposure is related to the development of otitis media, and AME and CME may have antioxidative and anti-inflammatory effects against lead toxicity.

Anti-apoptotic role of spermine against lead and/or gamma irradiation-induced hepatotoxicity in male rats

Exposure to either lead (Pb) or γ-irradiation (IR) results in oxidative stress in biological systems. Herein, we explored the potential anti-apoptotic effect of spermine (Spm) against lead and/or γ-irradiation-induced hepatotoxicity in male albino rats. Rats were divided into eight experimental groups of ten rats each: groups including negative control, whole body γ-irradiated (6 Gray (Gy)), lead acetate (PbAct) trihydrate orally administered (75 mg/kg bw ≡ 40 mg/kg bw Pb for 14 consecutive days), and Spm intraperitoneally dosed (10 mg/kg bw for 14 consecutive days) rats and groups subjected to combinations of Pb + IR, Spm + IR, Spm + Pb, and Spm + Pb followed by IR on day 14 (Spm + Pb + IR). A significant decrease in arginase activity as well as mRNA and protein levels of Bcl-2 and p21 was observed in rats intoxicated with Pb and/or γ-irradiation compared to controls, whereas Bax mRNA and protein levels were significantly increased. Also, an increased level of nitric oxide (NO) with a reduced arginase activity was observed in liver tissues of intoxicated rats. Spm co-treatment with lead and/or γ-irradiation attenuated the increase in Bax mRNA and protein expression, while it restored those of Bcl-2 and p21 together with NO levels and arginase activity to control values. Altogether, we suggest that Spm may be useful in combating free radical-induced apoptosis in Pb-intoxicated and/or γ-irradiated rats.

Omega-3 fatty acid attenuates oxidative stress in cerebral cortex, cerebellum, and hippocampus tissue and improves neurobehavioral activity in chronic lead-induced neurotoxicity

Objectives: In view of the increasing risk of lead on human health, the present study has been carried out to investigate the neuroprotective effect of omega-3 fatty acid on chronic lead-induced neurotoxicity and behavioral impairment in rats. Methods: Different neurobehavioral parameters, biochemical assays, and histopathological analyses in brain regions of rats were conducted. Results: Rats exposed to different doses of lead (lead acetate 2.5, 5.0, 7.5 mg/kg body weight p.o. for 90 days) caused a significant decrease in body weight, brain weight, and behavioral changes as compared to controls. Abnormal histopathological and increased levels of lead in blood and brain regions increased the levels of ROS, LPO, PCC and decreased the levels of GSH with concomitant reduction in SOD, CAT, and GPx activities in the brain region of rats treated with different doses of lead as compared to controls. Co-treatment of lead with omega-3 fatty acid (500 mg/kg body weight p.o. for 90 days) decreased the levels of ROS, LPO, PCC, and increased the level of GSH, also increased SOD, CAT, and GPx activity and showed improvements in behavioral as well as histopathological changes as compared to lead-treated groups. Discussion: Our results proved that omega-3 fatty acid improved behavioral deficits, altered histopathological and oxidative stress in lead-intoxicated rats. Among three different doses, 2.5 mg/kg b.wt. of lead along with omega-3 fatty acid was the most preventive dose for the neurotoxicity. This work reveals the potential of omega-fatty acid as a protective drug for lead neurotoxicity.

Antioxidant responses in gills and digestive gland of oyster Crassostrea madrasensis (Preston) under lead exposure

Crassostrea are ecologically and economically important bivalves and provide a good livelihood for coastal regions of many countries, including India. This study aims at evaluating the response of the antioxidant defense system in oyster Crassostrea madrasensis against lead (Pb) exposure under laboratory conditions. Antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), and glutathione-s-transferase (GST) and oxidative damage parameter lipid peroxidation (LPO) were measured in the gills and digestive glands of oysters exposed to 1-50µg/l of Pb (NO₃)₂ over a period of 8 days. LPO index increased progressively with increase in Pb concentration (1, 10, 25 and 50µg/l) in both tissues, gills and digestive gland. Although CAT and SOD activities induced together in the initial phase (upto 6th day), their activities decreased at a later stage of the experiment. However, GST activity increased on 8th day in both the tissues at concentration 10, 25 and 50µg/l indicates the compensatory defense mechanism against oxidative stress. The induced antioxidant responses recorded at 25 and 50µg/l of Pb concentrations suggest the presence of Pb-induced oxidative stress at these concentrations. The results of this work also indicate that LPO, SOD, and GST could be used as biomarkers to assess the impact of Pb on the C. madrasensis. This study concludes that any high level of dissolved Pb concentration (>10µg/l) in surrounding seawater could be harmful to the physiology of the C. madrasensis.

Lead Induced Hepato-renal Damage in Male Albino Rats and Effects of Activated Charcoal

Lead is a multi-organ toxicant implicated in various cancers, diseases of the hepatic, renal, and reproductive systems etc. In search of cheap and readily available antidote this study has investigated the role of activated charcoal in chronic lead exposure in albino rats. Eighteen mature male albino rats were used, divided into three groups of six rats per group. Group 1 (control rats) received deionised water (10 ml/kg), group 2 was given lead acetate solution 60 mg/kg and group 3 rats were given lead acetate (60 mg/kg) followed by Activated charcoal, AC (1000 mg/kg) by oral gavage daily for 28 days. Rats in group 2 showed significant increases in serum Aspartate aminotransferase, Alkaline phosphatase, Alanine aminotransferase, urea, bilirubin, total cholesterol, triglycerides, Low Density Lipoprotein, Very Low Density Lipoproteins, Total White Blood Cell Counts, Malondialdehyde, Interleukin-6, and decreases in Packed Cell Volume, hemoglobin concentration, Red blood cell count, total proteins, albumins, superoxide dismutase, glutathione peroxidase and total glutathione. Co-administration of AC significantly decreased these biomarkers with the exception of the sperm parameters. Histopathology of liver and kidney also confirmed the protective effective of AC against lead induced hepato-renal damage. AC may be beneficial in chronic lead induced liver and kidney damage.

Protective and ameliorative effect of sea buckthorn leaf extract supplementation on lead induced hemato-biochemical alterations in Wistar rats

Aim:

To evaluate the protective and ameliorative effect of aqueous sea buckthorn leaf extract (SLE) on hemato-biochemical profile in lead intoxicated Wistar rats.

Materials and Methods:

An experiment was conducted for 60 days. 36 adult male Wistar rats with a mean body weight of 177.8±12.6 g were divided into five groups and were subjected to various daily oral treatment regimens. Group I served as a negative control receiving only feed and water, Group II (positive control for lead) received lead acetate at 250 ppm in drinking water, and Group III (positive control for SLE) received SLE at 100 mg/kg b.wt. Animals in Group IV received a combination of lead acetate at 250 ppm in drinking water for the first 45 days and SLE at 100 mg/kg b.wt. throughout the experimental period of 60-day, and in Group V for the last 15 days of the trial after the administration of lead acetate until the first 45 days of the trial to study the protective and ameliorating effects of SLE, respectively. Blood samples were collected from retro-orbital fossa of each rat on 0^th, 45^th, and 60^th day of the experiment for hemato-biochemical analysis including hemoglobin (Hb), packed cell volume (PCV), serum total protein, albumin, globulin, albumin:globulin ratio, cholesterol, urea, and creatinine.

Results:

Significantly (p<0.01) lower levels of serum total proteins and albumin, and a significantly (p<0.01) higher serum cholesterol, urea and creatinine levels were observed in Group II (lead intoxicated group) in comparison to Group I (negative control). Administration of SLE at 100 mg/kg body wt. to lead intoxicated Wistar rats resulted in normalization of almost all the biochemical parameters studied in both the treatment Groups, i.e., IV and V (protective and ameliorative). However, the effects were more pronounced in the protective group. No effects of SLE supplementation were observed on Hb levels. PCV levels improved in protective groups, but no effect was observed in ameliorative group in comparison to lead intoxicated groups.

Conclusion:

SLE administration at 100 mg/kg b.wt. to lead intoxicated Wistar rats may be used to protect/ameliorate lead induced biochemical alterations in Wistar rats.

Alteration in bone geometric and mechanical properties, histomorphometrical parameters of trabecular bone, articular cartilage, and growth plate in adolescent rats after chronic co-exposure to cadmium and lead in the case of supplementation with green, black, red and white tea

Adolescent male Wistar rats were used to check whether regular consumption of black, red, white, or green tea would have a protective effect on femur development during 12-week exposure to Cd and Pb (7mg Cd and 50mg Pb in 1kg of the diet). The animals were randomly divided (n=12) into a positive control (without Cd, Pb and teas), a negative control group (Cd and Pb), and groups supplemented additionally with green (GT), black (BT), red (RT), and white tea (WT). Heavy metals reduced the geometric and densitometric parameters and the total thickness of articular cartilage irrespective of tea administration and influenced mechanical endurance, growth plate thickness, and trabecular histomorphometry depending on the tea type. It is difficult to indicate which tea has the best protective effects on bone and hyaline cartilage against heavy metal action.

Effects of Dietary Selenium Against Lead Toxicity on mRNA Levels of 25 Selenoprotein Genes in the Cartilage Tissue of Broiler Chicken

The interactions between the essential element selenium (Se) and the toxic element lead (Pb) have been reported extensively; however, little is known about the effect of Se on Pb toxicity and the expression pattern of selenoproteins in the cartilage of chicken. To investigate the effects of Se on Pb toxicity and the messenger RNA (mRNA) expressions of selenoproteins in cartilage tissue, an in vitro study was performed on 1-day-old broiler chickens (randomly allocated into four groups) with diet of different concentration of Se and Pb. After 90 days, the meniscus cartilage and sword cartilage tissue were examined for the mRNA levels of 25 selenoprotein genes. The results showed that Se and Pb influenced the expression of selenoprotein genes in the chicken cartilage tissue. In detail, Se could alleviate the downtrend of the expression of Gpx1, Gpx2, Gpx4, Txnrd2, Txnrd3, Dio1, Dio2, Seli, Selu, Sepx1, Selk, Selw, Selo, Selm, Sep15, Sepnn1, Sels, and Selt induced by Pb exposure in the meniscus cartilage. In the sword cartilage, Se alleviated the downtrend of the expression of Gpx2, Gpx3, Gpx4, Txnrd1, Txnrd2, Dio2, Dio3, Seli, Selh, SPS2, Sepx1, Selk, Selw, Selo, Selm, Sep15, Selpb, Sepn1, and Selt induced by Pb exposure. The present study provided some compensated data about the roles of Se against Pb toxicity in the regulation of selenoprotein expression.

The detrimental effects of lead on human and animal health

Lead, a chemical element in the carbon group with symbol Pb (from Latin: Plumbum, meaning “the liquid silver”) and has an atomic number 82 in the periodic table. It was the first element that was characterized by its kind of toxicity. In animal systems, lead (Pb) has been incriminated in a wide spectrum of toxic effects and it is considered one of the persistent ubiquitous heavy metals. Being exposed to this metal could lead to the change of testicular functions in human beings as well as in the wildlife. The lead poising is a real threat to the public health, especially in the developing countries. Accordingly, great efforts on the part of the occupational and public health have been taken to curb the dangers of this metal. Hematopoietic, renal, reproductive, and central nervous system are among the parts of the human body and systems that are vulnerable toward the dangers following exposure to high level of Pb. In this review, we discussed the massive harmful impact that leads acetate toxicity has on the animals and the worrying fact that this harmful toxicant can be found quite easily in the environment and abundance. Highlighting its (Pb) effects on various organs in the biological systems, its economic, as well as scientific importance, with the view to educate the public/professionals who work in this area. In this study, we focus on the current studies and research related to lead toxicity in animals and also to a certain extent toward human as well.

Arsenic and dichlorvos: Possible interaction between two environmental contaminants

Metals are ubiquitously present in the environment and pesticides are widely used throughout the world. Environmental and occupational exposure to metal along with pesticide is an area of great concern to both the public and regulatory authorities. Our major concern is that combination of these toxicant present in environment may elicit toxicity either due to additive or synergistic interactions or 'joint toxic actions' among these toxicants. It poses a rising threat to human health. Water contamination particularly ground water contamination with arsenic is a serious problem in today's scenario since arsenic is associated with several kinds of health problems, such arsenic associated health anomalies are commonly called as 'Arsenism'. Uncontrolled use and spillage of pesticides into the environment has resulted in alarming situation. Moreover serious concerns are being addressed due to their persistence in the environmental matrices such as air, soil and surface water runoff resulting in continuous exposure of these harmful chemicals to human beings and animals. Bio-availability of these environmental toxicants has been enhanced much due to anthropological activities. Dreadfully very few studies are available on combined exposures to these toxicants on the animal or human system. Studies on the acute and chronic exposure to arsenic and DDVP are well reported and well defined. Arsenic is a common global ground water contaminant while dichlorvos is one of the most commonly and widely employed organophosphate based insecticide used in agriculture, horticulture etc. There is thus a real situation where a human may get exposed to these toxicants while working in a field. This review highlights the individual and combined exposure to arsenic and dichlorvos on health.

Nano drug delivery systems: a new paradigm for treating metal toxicity

INTRODUCTION

The standard medical treatment for metal toxicity is chelation therapy. Chelating agents work by forming less toxic complexes with the toxic metal ions which are readily excreted from the body. These compounds, based on their hydrophilic/lipophilic property, can either remove toxic metal ions from extracellular sites or can penetrate the intracellular compartments to facilitate the removal of toxic metal ions. However, there are various disadvantages associated with this kind of therapy, notably, selectivity. Other problems and challenges are that the therapy regime is expensive, time consuming and has poor patient compliance. Two chelating agents, dimercaptosuccinic acid (DMSA) and dimercaptopropionicsulfonate (DMPS) have gained increased acceptance among clinicians, undoubtedly improving the management of metal intoxications.

AREAS COVERED

The present review provides an insight into the conventional chelating agents, new chelators under development, and the new opportunities presented by the use of nanotherapy for the treatment of metal poisoning cases.

EXPERT OPINION

Today's research should not only focus towards development of alternate chelators but also targeted therapy such as the nanotherapy.

Amelioration of cadmium- and mercury-induced liver and kidney damage in rats by genetically engineered probiotic Escherichia coli Nissle 1917 producing pyrroloquinoline quinone with oral supplementation of citric acid

OBJECTIVE

Antioxidants, chelating agents, and probiotics are used to manage the toxic effects of cadmium (Cd) and mercury (Hg). The aim of this study was to investigate the combined effects of antioxidants, chelating agents, and probiotics against heavy metal toxicity.

METHOD

Genetically modified probiotic Escherichia coli Nissle 1917 (EcN-20) producing a potent water soluble antioxidant pyrroloquinoline quinone (PQQ) was supplemented with oral citric acid and compared with another genetically modified probiotic EcN-21 producing PQQ and citric acid against oxidative stress induced by Cd and Hg. Rats were independently given 100 ppm Cd and 80 ppm Hg in drinking water for 4 wk.

RESULTS

EcN-20 was found to be more effective than EcN-2 (EcN strain with genomic integration of vgb and gfp genes) with orally given PQQ against oxidative stress induced by Cd and Hg. EcN-20 supplemented with oral citric acid was more effective against Cd and Hg toxicity compared with EcN-2+citric acid (oral), EcN-2+PQQ (oral), EcN-2+PQQ (oral)+citric acid (oral), EcN-20, and EcN-21. However, protection shown by EcN-21 was similar to EcN-20.

CONCLUSION

The combination therapy involving probiotic EcN-20 producing PQQ with citric acid given orally was found to be a moderately effective strategy against toxicity induced by Cd and Hg, whereas the protective effect of EcN-21 was the same as EcN-20.

Natural Antioxidants Against Arsenic-Induced Genotoxicity

Arsenic is present in water, soil, and air in organic as well as in inorganic forms. However, inorganic arsenic is more toxic than organic and can cause many diseases including cancers in humans. Its genotoxic effect is considered as one of its carcinogenic actions. Arsenic can cause DNA strand breaks, deletion mutations, micronuclei formation, DNA-protein cross-linking, sister chromatid exchange, and DNA repair inhibition. Evidences indicate that arsenic causes DNA damage by generation of reactive free radicals. Nutritional supplementation of antioxidants has been proven highly beneficial against arsenic genotoxicity in experimental animals. Recent studies suggest that antioxidants protect mainly by reducing excess free radicals via restoring the activities of cellular enzymatic as well as non-enzymatic antioxidants and decreasing the oxidation processes such as lipid peroxidation and protein oxidation. The purpose of this review is to summarize the recent literature on arsenic-induced genotoxicity and its mitigation by naturally derived antioxidants in various biological systems.

Lead Toxicity, Antioxidant Defense and Environment

Environmental and occupational exposure to a large number of chemicals occurs at various stages throughout human life. Many of these are devoid of toxicity, but some could pose a significant health risk, i.e. the exposure to environmental xenobiotic metals as lead, mercury (Sinicropi et al. 2010a; Carocci et al. 2014), cadmium, etc. In particular, lead has long been a widespread public concern (Basha and Reddy 2010). Lead is one of the earliest heavy metals discovered by men. Due to its unique properties, as low melting point, softness, malleability, ductility, and resistance to corrosion, men have used lead for the last 5000 years in a wide range of applications.

The lack of protective effects of tea supplementation on liver and jejunal epithelium in adult rats exposed to cadmium and lead

Adult rats at the age of 12 weeks were divided into the control group and groups supplemented with green (GT), black (BT), red (RT), or white (WT) tea extracts. The diet (except that for the control) was mixed with 7 mg Cd/kg and 50 mg Pb/kg. The experiment lasted 12 weeks. Basal haematology and plasma biochemical parameters as well as the histomorphometrical parameters of jejunal epithelium and liver were determined. The lowest body mass was found in the RT and WT groups. Some functional (increased plasma ALT and AST, and the de Ritis coefficient) and structural changes in the liver (slight fatty degenerative changes, an increase in the intercellular space) were evident irrespective of the type of tea in the Cd and Pb poisoned rats. This toxic effect was visible especially in rats drinking black or red tea. However, the rats had no elevated LDH and ALT activities. The highest content of Cd and Pb in the liver and blood plasma was found in rats drinking red tea. Based on the results obtained, it is clear that long-term exposure of adult rats with a mature intestinal barrier to Cd and Pb contamination, under higher exposure conditions than the current estimates of weekly exposure of the general population to Cd and Pb through diet, causes a toxic effect, especially in the liver, and can change the structure of intestinal mucosa, irrespective of tea administration.

Effects of vitamin E on lead-induced impairments in hippocampal synaptic plasticity

Lead (Pb) exposure during development is associated with impaired cognitive function and long-term potentiation (LTP). Vitamin E (VE) is an antioxidant that could have protective effects against Pb intoxication. In this study, we examined the protective effects of vitamin E against Pb-induced LTP impairments. Forty-six adult male Wistar rats were randomly divided into 6 treatment groups: (1) control; (2) Pb exposure; (3) VE; (4) Pb +VE; (5) Pb exposure followed by VE 2 months after exposure; (6) VE followed by Pb exposure 1 month after treatment. Rats were exposed to Pb through daily consumption of Pb-contaminated distilled water; VE was administered by daily gavage for 3 months. After this period, the population spike (PS) amplitudes and the slopes of excitatory postsynaptic potentials (EPSPs) were measured in the dentate gyrus (DG) area of the hippocampus in adult rats in response to electrical stimulation applied to the perforant pathway in vivo. Blood samples were also collected to evaluate malondialdehyde (MDA) levels, total antioxidant capacity (TAC), and total oxidant status (TOS). Biochemical analyses demonstrated significant increases in plasma MDA and TOS levels in the Pb-exposed group compared to the control group. VE-protected groups revealed significant increases in TAC levels. Our results demonstrate that Pb decreased EPSP slopes and PS amplitudes compared to the control group, whereas VE increased these parameters compared to the control group. Co-administration of VE with Pb exposure inhibited Pb-induced effects. These findings suggest that VE via its antioxidant activity reverses Pb-induced impairments of synaptic plasticity in the DG.

Oral nanoparticulate curcumin combating arsenic-induced oxidative damage in kidney and brain of rats

Arsenic exposure through drinking water causes oxidative stress and tissue damage in the kidney and brain. Curcumin (CUR) is a good antioxidant with limited clinical application because of its hydrophobic nature and limited bioavailability, which can be overcome by the encapsulation of CUR with nanoparticles (NPs). The present study investigates the therapeutic efficacy of free CUR and NP-encapsulated CUR (CUR-NP) against sodium arsenite-induced renal and neuronal oxidative damage in rat. The CUR-NP prepared by emulsion technique and particle size ranged between 120 and 140 nm, with the mean particle size being 130.8 nm. Rats were divided into five groups (groups 1–5) with six animals in each group. Group 1 served as control. Group 2 rats were exposed to sodium arsenite (25 ppm) daily through drinking water for 42 days. Groups 3, 4, and 5 were treated with arsenic as in Group 2; however, these animals were also administered with empty NPs, CUR (100 mg/kg body weight), and CUR-NP (100 mg/kg), respectively, by oral gavage during the last 14 days of arsenic exposure. Arsenic exposure significantly increased serum urea nitrogen and creatinine levels. Arsenic increased lipid peroxidation (LPO), reduced glutathione content and the activities of superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase were depleted significantly in both kidney and brain. Treatment with free CUR and CUR-NP decreased the LPO and increased the enzymatic and nonenzymatic antioxidant system in kidney and brain. Histopathological examination showed that kidney and brain injury mediated by arsenic was ameliorated by treatment. However, the amelioration percentage indicates that CUR-NP had marked therapeutic effect on arsenic-induced oxidative damage in kidney and brain tissues.

Toxicity of cadmium and protective effect of bee honey, vitamins C and B complex

The present work aimed to study the toxic effect of cadmium (Cd) on rabbits' blood indices, as well as the therapeutic effect of the antioxidant agents, vitamins C and B complex and bee honey on Cd intoxicated rabbits. Cadmium chloride (CdCl2) was injected subcutaneously at a dose of 3 mg/kg of body weight. The results showed a significant increase in serum glucose, triglycerides, cholesterol, total protein, albumin, globulin, urea and creatinine, compared to the control group. In addition, CdCl2 intoxication increased the levels of uric acid, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase and bilirubin. Concerning haematological parameters, the more obvious changes were an increase in mean corpuscular volume and a decrease in white blood cells count, platelets, lymphocytes, heamatocrit, haemoglobin and red blood cells count. Treatment of CdCl2-intoxicated animals with vitamins C and B complex and bee honey showed a decrease in the harmful effects of Cd by restoring haematological and biochemical changes. Bee honey treatment was the most effective in providing recoveries in the altered blood parameters.

Moringa oleifera hydroethanolic extracts effectively alleviate acetaminophen-induced hepatotoxicity in experimental rats through their antioxidant nature

The aim of the study was to investigate the in vitro antioxidant properties Moringa oleifera Lam. (MO) extracts and its curative role in acetaminophen (APAP)- induced toxic liver injury in rats caused by oxidative damage. The total phenolic content and antioxidant properties of hydroethanolic extracts of different MO edible parts were investigated by employing an established in vitro biological assay. In the antihepatotoxic study, either flowers or leaves extract (200 mg/kg or 400 mg/kg, i.p) were administered an hour after APAP administration, respectively. N-Acetylcysteine was used as the positive control against APAP-induced hepatotoxicity. The levels of liver markers such as alanine aminotransferase (ALT) and the levels of oxidative damage markers including malondialdehyde (MDA), 4-hydroxynonenal (4-HNE) protein adduct, reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) were analysed and compared between experimental groups. Among MO edible parts the flower extracts contain the highest total phenolic content and antioxidant capacity, followed by leaves extract. The oxidative marker MDA, as well as 4-HNE protein adduct levels were elevated and GSH, SOD and CAT were significantly decreased in groups treated with hepatotoxin. The biochemical liver tissue oxidative markers measured in the rats treated with MO flowers and leaves hydroethanolic extracts showed a significant (p < 0.05) reduction in the severity of the liver damage. The results of this study strongly indicate the therapeutic properties of MO hydroethanolic extracts against acute liver injury and thereby scientifically support its traditional use.