Lead Toxicity, Antioxidant Defense and Environment

CdS Semiconductor Quantum Dots; Facile Synthesis, Application as Off Fluorescent Sensor for Detection of Lead (Pb2+) Ions and Catalyst for Degradation of Dyes from Water

The CdS quantum dots (QDs) were prepared by rapid, one-pot, and novel photochemical method, which used Thioglycolic acid (TGA) molecules as both stabilizer and sulfur source. The structure and morphology of the prepared CdS QDs were characterized by different analyses such as XRD, FT-IR, Raman, EDS, TEM, PL, and absorption. In this work, was used of CdS QDs as off fluorescence sensor for rapid and simple detection of lead (Pb2+) ions in water. The PL intensity of CdS QDs in the presence of lead ions decreased gradually and in the presence of 100 μM lead ions, photo emission completely quenched. The photocatalyst performance of CdS QDs was investigated by methylene blue (MB), methylene orange (MO), and rhodamine b (RB) pollutant dyes under both UV and sun lights. The obtained results showed that CdS QDs had excellent photocatalyst activity with dyes under UV light and 94.9% of MO dye, 94.4% of RB dye, and 81.2% of MB was degraded after 60 min UV irradiation. For understanding about which parameter have a key role in the photodegradation process of MO by CdS QDs under UV illumination, several radical scavengers were used, and results showed that holes have a key role in the degradation process.

Potential Toxic elements in shellfish from three rivers in Niger Delta, Nigeria: bioaccumulation, dietary intake, and human health risk assessment

Human health risks associated with the consumption of three shellfish (Penaeus monodon, Crassostrea rhizophorae, and Tympanostomus fuscatus) harvested from the Buguma, Krakrama, and Bonny Rivers in the Niger Delta region were evaluated in this study. The bioaccumulation of potential toxic elements (PTEs) [Arsenic (As), Cadmium (Cd), Chromium (Cr), Lead (Pb), and Nickel (Ni)] was analyzed using atomic absorption spectrophotometry (AAS). The pollution index (PPI), estimated daily intake (EDI), target hazard quotient (THQ), total hazard index (HI), target cancer risk (CR), and total cancer risk (TCR) were evaluated for potential human health risks. The bioaccumulation levels of PTEs in shellfish samples followed the order: Ni > Cr > Pb > Cd > As and were above standard recommended limits except for inorganic As levels observed in T. fuscatus and P. monodon samples from Krakrama and Bonny and C. rhizophorae from Bonny river. The EDI values for iAs, Cr, and Ni were lower than the tolerable daily intake (TDI), however, the EDI of Cd for children in P. monodon (4.6E-03 mg kg-1day-1), T. fuscatus (1.7E-03 mg kg-1day-1) and C. rhizophorae (1.4E-03 mg kg-1day-1) from Buguma were higher than the TDI value (8.00E-04 mg kg-1day-1). The HI values were above 1. The total cancer risk (TCR) values of all analyzed PTEs for all the shellfish species from the rivers for children and adults ranged from 8.69E-04 to 2.47E-03 and 1.86E-03 to 5.30E-03 respectively and these were higher than the priority risk level (1E-04), hence, the need to monitor shellfish consumption in the study area.

Sodium Para-Aminosalicylic Acid Modulates Autophagy to Lessen Lead-Induced Neurodegeneration in Rat Cortex

Lead (Pb) is a common heavy metal contaminant in the environment, and it may perturb autophagy and cause neurodegeneration. Although sodium para-aminosalicylic (PAS-Na) has been shown to protect the brain from lead-induced toxicity, the mechanisms associated with its efficacy have yet to be fully understood. In this study, we evaluated the efficacy of PAS-Na in attenuating the neurotoxic effects of lead, as well as the specific mechanisms that mediate such protection. Lead exposure resulted in weight loss and injury to the liver and kidney, and PAS-Na had a protective effect against this damage. Both short-term and subchronic lead exposure impaired learning ability, and this effect was reversed by PAS-Na intervention. Lead exposure also perturbed autophagic processes through the modulation of autophagy-related factors. Short-term lead exposure downregulated LC3 and beclin1 and upregulated the expression of p62; subchronic lead exposure upregulated the expression of LC3, beclin1, and P62. It follows that PAS-Na had an antagonistic effect on the activation of the above autophagy-related factors. Overall, our novel findings suggest that PAS-Na can protect the rat cortex from lead-induced toxicity by regulating autophagic processes. (1) Short-term lead exposure inhibits autophagy, whereas subchronic lead exposure promotes autophagy. (2) PAS-NA ameliorated the abnormal process of lead-induced autophagy, which had a protective effect on the cerebral cortex.

Curcumin and cinnamon mitigates lead acetate-induced oxidative damage in the spleen of rats

Lead toxicity is a common occupational and environmental health hazard that exerts many toxic effects on animals and humans, including immunotoxicity. Curcumin (CUR) and cinnamon (CIN) are common medicinal herbs with immunostimulatory and antioxidant properties. Therefore, this study investigated the protective effect of curcumin and cinnamon against lead acetate (LA)-induced splenotoxicity in rats via hemato-biochemical, immunological, oxidative stress marker, CYP-2E1 expression, histological, and immunohistological evaluations. Four groups of seven rats each were used: the control group received corn oil as a vehicle; the lead acetate group received (100 mg/kg), the CUR + LA group received curcumin (400 mg/kg) plus lead acetate, and the CIN + LA group received cinnamon (200 mg/kg) plus lead acetate orally for 1 month. LA exposure induced macrocytic hypochromic anemia, leukocytosis, neutrophilia, monocytosis, and lymphopenia. Additionally, significant elevations in serum iron, ferritin levels, and transferrin saturation percentage with significant decline of total and unsaturated iron binding capacities (TIBC and UIBC), transferrin, and immunoglobulin G and M levels were recorded. In addition, lead acetate significantly upregulated splenic CYP-2E1 expression, that was evident by significant depletion of reduced glutathione (GSH) activity and elevation of malondihyde (MDA), nitric oxide (NO), and protein carbonyl (PC) concentrations in the spleen. Histologically, hyperplasia of lymphoid follicles, hemosiderin deposition, and disturbance of CD3 and CD68 immuno-expressions were evident in the spleen from the lead acetate group. However, curcumin and cinnamon administration restored the hemato-biochemical, immunological, and oxidative stress parameters as well as histological and immunohistological pictures toward normalcy. In conclusion, curcumin and cinnamon can partially ameliorate LA-induced oxidative damage in the spleen, possibly through their antioxidant, immunomodulatory, and gene-regulating activities.

Relationship between Postural Stability, Lead Content, and Selected Parameters of Oxidative Stress

This study attempts to determine whether the increased blood lead concentration affects the posturographic test and to determine the relationship between the parameters of posture stability and selected parameters of oxidative stress. The study population consisted of 268 male employees and was divided into two equal subgroups, depending on the lead content in the blood. A posturographic examination was performed. Concentrations of lead, cadmium, zinc protoporphyrin, selected essential elements, and selected markers of oxidative stress in the blood were tested. Higher blood lead concentrations positively affected the values of the sway results: the field and the mean velocity of the center of the feet pressure in posturography. The absolute value of the proprioception ratio was similar in both subgroups. The content of malondialdehyde shows a statistically significantly higher value in a subgroup with high blood lead concentration and exhibits significant correlations only with some of the posturography parameters. The lipofuscin content in erythrocytes correlates with the results of the posturography test. Zinc protoporphyrin, total oxidant status, total antioxidant capacity, selected minerals, and metals did not correlate with the results of the posturography test. In conclusion, posturographic results correlate only with selected markers of oxidative stress, so it can be assumed that the effect on the body balance is only partial.

Possible role of lead in breast cancer - a case-control study

Numerous risk factors have been associated with breast cancer (BC), exposure to metalloestrogen, like lead, being such. Since lead involvement in BC is still equivocal, we focused on lead levels in three compartments of BC patients, blood, healthy, and malignant tissues. Also, as the cholesterol role in cancer development was recognized at the beginning of the twentieth century and led to involvement in lipid profile impairment, we further extend our research on lipid profile and enzymes responsible for maintaining lipid balance in BC patients. Fifty-five women diagnosed with BC were enrolled in the study. Forty-one healthy women represented the control group. Lead levels in blood, healthy surrounding and malignant tissue, and lipid profile parameters in serum, were determined. Higher lead levels were obtained in surrounding healthy tissue samples compared to cancerous tissue samples, while blood lead levels of BC women did not differ significantly from the control group. The altered lipid profile scheme in women diagnosed with breast cancer contained significantly higher triglycerides levels (P < 0.001). Moreover, logistic regression analysis revealed triglycerides as a significant predictor of BC (OR = 2.6; P < 0.01). Although statistical significance was missing for lower paraoxonase-1 (PON-1) activities observed in BC women, multivariate logistic regression singled out PON-1 activities as significant BC predictors. The result of the present study further indicated oxidative status imbalance and tissue levels bioelements perturbation. Obtained results in the present study propose possible lead involvement in BC onset accompanied with bioelements redistribution and oxidative stress occurrence.

Health Risk Assessment and Multivariate Statistical Analysis of Heavy Metals in Vegetables of Khyber Pakhtunkhwa Region, Pakistan

The level of heavy metals in vegetables grown in soil irrigated with various sources of water and the health risks associated with the consumption of these vegetables were assessed in this study. Samples of water, soil, and vegetables were collected from farmer fields. After digestion in acidic solution, analytical measurements were made using an atomic absorption spectrophotometer. The mean concentration of Pb, Cr, Cd, Cu, Zn, Ni, Fe, and Mn in the soil of two sampling area were in the range from 60.00 to 84.00 mg kg^-1, 68.00 to 98.00 mg kg^-1, 1.60 to 2.60 mg kg^-1, 26.10 to 33.20 mg kg^-1, 22.60 to 30.80 mg kg^-1, 50.10 to 78.30 mg kg^-1, 420.00 to 471.00 mg kg^-1, and 270.20 to 340.50 mg kg^-1, respectively. Heavy metals in soil varied significantly at (P ≤ 0.001) among sampling area. The nine heavy metals were divided into two clusters for wastewater and soil, according to cluster analysis. The number of variables was reduced using principal component analysis, which yielded three latent factors, one for wastewater and one for soil. Pb, Cr, Cd, Cu, Zn, Ni, Fe, and Mn concentrations were significantly higher at P ≤ 0.001 in nine vegetables grown on soil irrigated with untreated wastewater than in vegetables grown on fresh-tube well-water-irrigated soil. The health risks associated with metal intake were assessed using the estimated daily intake of metals (EDIM), hazard quotients (HQs), and hazard index (HI). The rates of metal transfer to vegetables have been determined. Except for Pb and Cd, all of the elements' EDMI values were found to be lower than their RfD values. The corresponding HRI values of metals in the various vegetables were found to be below 1, implying that vegetable consumption in the studied region poses no carcinogenic risk. Constant determination of heavy metals in all fruits and vegetables is essential for the assessment of health risks associated with dietary metal exposure. The study has provided valuable information to the general public about the use of wastewater for irrigation of vegetables.

Lead in the marine environment: concentrations and effects on invertebrates

Lead (Pb) is a non-essential metal naturally present in the environment and often complexed with other elements (e.g., copper, selenium, zinc). This metal has been used since ancient Egypt and its extraction has grown in the last centuries. It has been used until recently as a fuel additive and is currently used in the production of vehicle batteries, paint, and plumbing. Marine ecosystems are sinks of terrestrial contaminations; consequently, lead is detected in oceans and seas. Furthermore, lead is not biodegradable. It remains in soil, atmosphere, and water inducing multiple negative impacts on marine invertebrates (key species in trophic chain) disturbing ecological ecosystems. This review established our knowledge on lead accumulation and its effects on marine invertebrates (Annelida, Cnidaria, Crustacea, Echinodermata, and Mollusca). Lead may affect different stages of development from fertilization to larval development and can also lead to disturbance in reproduction and mortality. Furthermore, we discussed changes in the seawater chemistry due to Ocean Acidification, which can affect the solubility, speciation, and distribution of the lead, increasing potentially its toxicity to marine invertebrates.

Relationship between lead absorption and iron status and its association with oxidative stress markers in lead-exposed workers

BACKGROUND

The emission of lead (Pb) occurring during the extraction, processing and industrial applications of this element remains a significant environmental risk factor. The absorbability of lead in humans is strongly associated with the general health status of exposed individuals. Existing mineral deficiencies are considered being a predisposition to an increased Pb uptake. Both, iron deficiency and lead poisoning are the major causative factors responsible for the prevalence of anemia within the vulnerable population, especially in children. Although some of the intervention programs of counteracting lead poisoning by iron supplementation proved to be effective in the Pb-exposed population, the exact mechanisms of this interaction still require further studies. The objective of the presented study was to examine the association of iron level on oxidative stress measures and its effects on the severity of lead toxicity in the exposed population.

METHODS

The analyzed population consisted of 270 male workers from the lead-zinc smelter. The studied population was divided into two sub-groups based on the serum iron concentration: low iron level group (L-Fe; Fe < median value) and high iron level group (H-Fe; Fe > median value). Measured traits comprised of blood lead (PbB), serum Fe and zinc protoporphyrin (ZPP) levels as well as a blood count and oxidative stress markers.

RESULTS

No significant correlation between serum iron concentration and PbB in the tested cohort was found. On the contrary, the analysis of ZPP levels (long-term marker related to a hematologic toxic effect of Pb) within the subgroups differing in serum Fe level shown that ZPP was 12.3 % lower (p = 0.043) in subjects classified within the H-Fe group. A positive correlation of serum Fe and total antioxidant capacity (TAC) was found (R = 0.1999). The conducted 3-D PCA analysis showed that individuals classified within the H-Fe group were characterized by the co-occurrence of higher Fe levels, lower ZPP, and higher TAC value.

CONCLUSION

These results support the existing evidence providing that maintaining the optimal status of Fe may play a significant role in preventing the lead poisoning and alleviating harmful effects of Pb on the oxidative balance in humans.

Elemental Speciation Analysis in Environmental Studies: Latest Trends and Ecological Impact

Speciation analysis is a key aspect of modern analytical chemistry, as the toxicity, environmental mobility, and bioavailability of elemental analytes are known to depend strongly on an element’s chemical species. Henceforth, great efforts have been made in recent years to develop methods that allow not only the determination of elements as a whole, but also each of its separate species. Environmental analytical chemistry has not ignored this trend, and this review aims to summarize the latest methods and techniques developed with this purpose. From the perspective of each relevant element and highlighting the importance of their speciation analysis, different sample treatment methods are introduced and described, with the spotlight on the use of modern nanomaterials and novel solvents in solid phase and liquid-liquid microextractions. In addition, an in-depth discussion of instrumental techniques aimed both at the separation and quantification of metal and metalloid species is presented, ranging from chromatographic separations to electro-chemical speciation analysis. Special emphasis is made throughout this work on the greenness of these developments, considering their alignment with the precepts of the Green Chemistry concept and critically reviewing their environmental impact.

Phycoremediation and photosynthetic toxicity assessment of lead by two freshwater microalgae Scenedesmus acutus and Chlorella pyrenoidosa

Heavy metal (HM) pollution is a serious agro-economic concern and algae can be used as one of the bioremediating agents as it can grow in different water bodies. In this study, the Scenedesmus acutus and Chlorella pyrenoidosa were exposed to various concentrations of Pb²⁺ for 96 h and a multidimensional toxicity assessment has been performed by pulse amplitude modulation technique and Fourier transform infrared spectroscopy (FTIR). High-angle annular dark-field scanning transmission electron microscopy coupled energy dispersive spectroscopy (HAADF-S/TEM-EDS) detected intracellular localization of Pb²⁺ , thus confirming algal bio-accumulation abilities. Sensitivity assay demonstrated that 500 and 400 ppm of Pb²⁺ as minimum inhibitory concentrations (MIC50) for S. acutus and C. pyrenoidosa, respectively, which inhibited growth (OD) by >50% in 96 h. During bioremoval studies, S. acutus and C. pyrenoidosa were found to remove ∼52 and ∼32% of total Pb²⁺ , respectively. The particulate analysis of Pb²⁺ by ICP-OES showed >99.5% biosorption capacity by both the species. The biomass characterization by FTIR showed the involvement of various cell wall functional groups such as hydroxyl, alkane, and C=C groups in the biosorption of Pb²⁺ by both the species. The noninvasive chlorophyll fluorescence techniques provide a quick insight on heavy metal stress and can be adapted as a rapid detection tool to study the Pb²⁺ stress. S. acutus strain showed higher tolerance and higher bioremoval capacity than C. pyrenoidosa. However, both the species can be exploited for biosorption of Pb²⁺ from aquatic streams as an alternative way for low cost Pb²⁺ recovery systems.

N,N'bis-(2-mercaptoethyl) isophthalamide (NBMI) exerts neuroprotection against lead-induced toxicity in U-87 MG cells

N,N'-bis(2-mercaptoethyl)isophthalamide (NBMI) is a novel lipophilic heavy metal chelator and thiol redox antioxidant. This study was designed to investigate the neuroprotective activity of NBMI in U-87 MG cells exposed to lead acetate (PbAc). Cells were pretreated with NBMI for 24 h prior to a 48 h exposure to PbAc. Cell death (55%, p < 0.0001) and reduction of intracellular GSH levels (0.70-fold, p < 0.005) induced by 250 µM Pb were successfully attenuated by NBMI pretreatment at concentrations as low as 10 µM. A similar pretreatment with the FDA-approved Pb chelator dimercaptosuccinic acid (DMSA) proved ineffective, indicating a superior PKPD profile for NBMI. Pretreatment with NBMI successfully counteracted Pb-induced neuroinflammation by reducing IL-1β (0.59-fold, p < 0.05) and GFAP expression levels. NBMI alone was also found to significantly increase ferroportin expression (1.97-fold, p < 0.05) thereby enhancing cellular ability to efflux heavy metals. While no response was observed on the apoptotic pathway, this study demonstrated for the first time that necrotic cell death induced by Pb in U-87 MG cells is successfully attenuated by NBMI. Collectively these data demonstrate NBMI to be a promising neuroprotective compound in the realm of Pb poisoning.

Advanced mechanotherapy: Biotensegrity for governing metastatic tumor cell fate via modulating the extracellular matrix

Mechano-transduction is the procedure of mechanical stimulus translation via cells, among substrate shear flow, topography, and stiffness into a biochemical answer. TAZ and YAP are transcriptional coactivators which are recognized as relay proteins that promote mechano-transduction within the Hippo pathway. With regard to healthy cells in homeostasis, mechano-transduction regularly restricts proliferation, and TAZ and YAP are totally inactive. During cancer development a YAP/TAZ - stimulating positive response loop is formed between the growing tumor and the stiffening ECM. As tumor developments, local stromal and cancerous cells take advantage of mechanotransduction to enhance proliferation, induce their migratory into remote tissues, and promote chemotherapeutic resistance. As a newly progresses paradigm, nanoparticle-conjunctions (such as magnetic nanoparticles, and graphene derivatives nanoparticles) hold significant promises for remote regulation of cells and their relevant events at molecular scale. Despite outstanding developments in employing nanoparticles for drug targeting studies, the role of nanoparticles on cellular behaviors (proliferation, migration, and differentiation) has still required more evaluations in the field of mechanotherapy. In this paper, the in-depth contribution of mechano-transduction is discussed during tumor progression, and how these consequences can be evaluated in vitro.

Lead uptake and translocation pathways in soybean seedlings: the role of ion competition and transpiration rates

Glycine max (L.) Merr. (soybean) crop plants have been found to have high lead (Pb) levels in aerial organs; however, knowledge about the processes involved in the incorporation, and subsequent translocation and accumulation of the metal in the plants is scarce. Considering the toxicity of this heavy metal, the aim of the present study was to evaluate Pb uptake and translocation, and their toxic effects on soybean seedlings via experiments of ionic competition with Ca2+ (2.5 mM, Ca:Pb 1:1) and alteration of the transpiration flow [0.25 mM Pb(NO3)2]. The following variables were analyzed: biomass, leaf area (morphological parameters), photosynthetic efficiency, biochemical response (considered physiological stress markers: antioxidant power, chlorophylls, carotenoids, starch, proteins, sugars, and malondialdehyde), and Pb content. Results showed that soybean seedlings can accumulate high Pb concentration in its organs; however, in general, no morpho-physiological Pb stress symptoms were observed, except for lipid peroxidation and antioxidant power. The treatment with Ca ions was not effective in reducing Pb entry into root over time when both Ca and Pb where present in the grow solution. Alteration of the transpiration rate in soybean showed that the air flow increased the consumption of solutions, regardless of the treatments. However, Pb accumulation was lower in seedlings exposed to air flow, indicating a selective exclusion of the metal in the solution. In both experiments, soybean seedlings showed to be tolerant to high Pb concentrations.

MOLECULAR MECHANISMS OF LEAD NEUROTOXICITY

Lead (Pb2+) is a non-essential metal with numerous industrial applications that have led to ts ubiquity in the environment. Thus, not only occupational-exposed individuals' health is compromised, but also that of the general population and in particular children. Notably, although the central nervous system is particularly susceptible to Pb2+, other systems are affected as well. The present study focuses on molecular mechanisms that underlie the effects that arise from the presence of Pb2+ in situ in the brain, and the possible toxic effects that follows. As the brain barriers represent the first target of systemic Pb2+, mechanisms of Pb2+ entry into the brain are discussed, followed by a detailed discussion on neurotoxic mechanisms, with special emphasis on theories of ion mimicry, mitochondrial dysfunction, redox imbalance, and neuroinflammation. Most importantly, the confluence and crosstalk between these events is combined into a cogent mechanism of toxicity, by intertwining recent and old evidences from humans, in vitro cell culture and experimental animals. Finally, pharmacological interventions, including chelators, antioxidants substances, anti-inflammatory drugs, or their combination are reviewed as integrated approaches to ameliorate Pb2+ harmful effects in both developing or adult organisms.

Antioxidative properties of Ocimum gratissimum alters Lead acetate induced oxidative damage in lymphoid tissues and hematological parameters of adult Wistar rats

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Chronic lead toxicity was induced in male rats by oral administration of lead acetate.

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Effect of Ocimum gratissimum in lead acetate toxicity on spleen, thymus, and blood.

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Oral lead acetate administration led to oxidative damage in spleen, thymus and blood.

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Ocimum gratissimum extract reversed oxidative stress and enhanced antioxidant enzymes.

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Ocimum gratissimum averts lead acetate-induced toxicity in the blood, thymus and spleen.

Lead exposure is a well-known environmental hazard. Its accumulation in humans may pose a danger to health. The present study investigated the beneficial effect of Ocimum gratissimum extract (OG) in reducing lead acetate (LA) induced oxidative damage in the spleen, thymus, and hematological indices. We employed an in vivo model of LA induced Wistar rats and administered 125 mg/kg/bw and 250 mg/kg/bw of OG extracts respectively. Our control groups were divided into 2; the first group received normal saline, feed, and water while the second group was administered OG extracts only. We assessed the levels of malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT) in the thymus and spleen and estimated percentages of blood cells. Our results showed that LA induces oxidative damage by significantly elevating MDA and diminishing GSH levels, SOD, and CAT activities. LA administration led to a significant decline in blood parameters. However, co-administration with OG compensated oxidative stress by significantly reducing MDA, increasing GSH, SOD, and CAT. Oral administration of OG to rats attenuated anemia, thrombocytopenia, leucocytosis, eosinophilia, monocytosis, and neutropenia induced by LA. The present study indicates that LA induced Spleen, thymus, and blood toxicity, which was reversed by oral OG administration.

Forced swimming stress increases natatory activity of lead-exposed mice

Recent evidence points to the relationship between lead toxicity and the function of the hypothalamic-pituitary-adrenal axis, which suggests that lead exposure could influence how an individual cope with stress. Here we test this hypothesis by investigating the behavioral effects of lead exposure in mice during the forced swimming test (FST), a parading in which animals are exposed to a stressful situation and environment. Swiss mice received either 180 ppm or 540 ppm of lead acetate (Pb) in their ad-lib water supply for 60-90 days, starting at postnatal day 30. Control (Ctrl) mice drank tap water. At the end of the exposure period, mice were submitted to a 5-min session of FST or to an open-field session of the same duration. Data from naïve animals showed that corticosterone levels were higher for animals tested in the FST compared to animals tested in the open-field. Blood-lead levels (BLL) in Pb-exposed mice ranged from 14.3 to 106.9 µg/dL. No differences were observed in spontaneous locomotion between Ctrl and Pb-exposed groups in the open-field. However, in the FST, Pb-treated mice displayed higher swimming activity than Ctrl ones and this effect was observed even for animals with BLL higher than 20 µg/dL. Furthermore, significant differences in brain glutathione levels, used as an indicator of led toxicity, were only observed for BLL higher than 40 µg/dL. Overall, these findings suggest that swimming activity in the FST is a good indicator of lead toxicity and confirm our prediction that lead toxicity influences behavioral responses associated to stress.

The Double Face of Metals: The Intriguing Case of Chromium

Chromium (Cr) is a common element in the Earth’s crust. It may exist in different oxidation states, Cr(0), Cr(III) and Cr(VI), with Cr(III) and Cr(VI) being relatively stable and largely predominant. Chromium’s peculiarity is that its behavior relies on its valence state. Cr(III) is a trace element in humans and plays a major role in glucose and fat metabolism. The beneficial effects of Cr(III) in obesity and types 2 diabetes are known. It has been long considered an essential element, but now it has been reclassified as a nutritional supplement. On the other hand, Cr(VI) is a human carcinogen and exposure to it occurs both in occupational and environmental contexts. It induces also epigenetic effects on DNA, histone tails and microRNA; its toxicity seems to be related to its higher mobility in soil and swifter penetration through cell membranes than Cr(III). The microorganisms Acinetobacter sp. Cr1 and Pseudomonas sp. Cr13 have been suggested as a promising agent for bioremediation of Cr(VI). This review intends to underline the important role of Cr(III) for human health and the dangerousness of Cr(VI) as a toxic element. The dual and opposing roles of this metal make it particularly interesting. An overview of the recent literature is reported in support.

Synergistic protective effect of Beta vulgaris with meso-2,3-dimercaptosuccinic acid against lead-induced neurotoxicity in male rats

Lead (Pb) toxicity is one of the most prevalent causes of human neurotoxicity. The available chelator drugs used now have many adverse effects. So, in this study, the protective role of Beta vulgaris juice (BVJ) on rat neurotoxicity induced by Pb was evaluated and the results were compared with the results of dimercaptosuccinic acid (DMSA, as used drug). Additionally, the synergistic effect of BVJ and DMSA against Pb-induced neurotoxicity was assessed. The study focused on the determination of the antioxidant, anti-inflammatory, and neurological potential of BVJ (alone, and with DMSA) towards lead-induced neurotoxicity. Also, the characterization of BVJ was studied. The results showed that BVJ contains considerable quantities of polyphenols, triterpenoids, and betalains which play an important role as antioxidants and anti-inflammatory. BVJ exhibited a protective effect against neurotoxicity via the reduction of Pb levels in blood and brain. Moreover, BVJ decreased the oxidative stress, inflammation, and cell death induced by Pb. Also, BVJ regulated the activities of acetylcholine esterase and monoamine oxidase-A which changed by Pb toxicity. BVJ and DMSA combination displayed a synergistic antineurotoxic effect (combination index ˂ 1). These results were in harmony with brain histopathology. Conclusion: BVJ has a powerful efficacy in the protection from brain toxicity via diminishing Pb in the brain and blood circulation, resulting in the prevention of the oxidative and inflammatory stress. Treatment with BVJ in combination with DMSA revealed a synergistic effect in the reduction of neurotoxicity induced by Pb. Also, the antioxidant and anti-inflammatory effects of the BVJ lead to the improvement of DMSA therapy.

The Effects of Cadmium Toxicity

Cadmium (Cd) is a toxic non-essential transition metal that poses a health risk for both humans and animals. It is naturally occurring in the environment as a pollutant that is derived from agricultural and industrial sources. Exposure to cadmium primarily occurs through the ingestion of contaminated food and water and, to a significant extent, through inhalation and cigarette smoking. Cadmium accumulates in plants and animals with a long half-life of about 25-30 years. Epidemiological data suggest that occupational and environmental cadmium exposure may be related to various types of cancer, including breast, lung, prostate, nasopharynx, pancreas, and kidney cancers. It has been also demonstrated that environmental cadmium may be a risk factor for osteoporosis. The liver and kidneys are extremely sensitive to cadmium's toxic effects. This may be due to the ability of these tissues to synthesize metallothioneins (MT), which are Cd-inducible proteins that protect the cell by tightly binding the toxic cadmium ions. The oxidative stress induced by this xenobiotic may be one of the mechanisms responsible for several liver and kidney diseases. Mitochondria damage is highly plausible given that these organelles play a crucial role in the formation of ROS (reactive oxygen species) and are known to be among the key intracellular targets for cadmium. When mitochondria become dysfunctional after exposure to Cd, they produce less energy (ATP) and more ROS. Recent studies show that cadmium induces various epigenetic changes in mammalian cells, both in vivo and in vitro, causing pathogenic risks and the development of various types of cancers. The epigenetics present themselves as chemical modifications of DNA and histones that alter the chromatin without changing the sequence of the DNA nucleotide. DNA methyltransferase, histone acetyltransferase, histone deacetylase and histone methyltransferase, and micro RNA are involved in the epigenetic changes. Recently, investigations of the capability of sunflower (Helianthus annuus L.), Indian mustard (Brassica juncea), and river red gum (Eucalyptus camaldulensis) to remove cadmium from polluted soil and water have been carried out. Moreover, nanoparticles of TiO2 and Al2O3 have been used to efficiently remove cadmium from wastewater and soil. Finally, microbial fermentation has been studied as a promising method for removing cadmium from food. This review provides an update on the effects of Cd exposure on human health, focusing on the cellular and molecular alterations involved.

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.

Therapeutic role of garlic and vitamins C and E against toxicity induced by lead on various organs

Due to industrial and urban sewage, the metal contaminations in aquatic and terrestrial environments are increasing day by day, especially in developing countries. Despite the study of several years, we are inert far away from an actual medication for prolonged toxicity of heavy metals such as mercury, lead, cadmium etc. Lead is one of the most common heavy metals that possess toxicological effects on numerous tissues of animals as well as humans. Several toxic effects of lead on reproductive organs, renal system, central nervous system, liver, lungs, blood parameters, and bones have been reported. On the other hand, several reports depicted that garlic is operative in declining the absorption of lead in bones as well as soft tissues. A combination of vitamin C and vitamin E enhances the biological recovery induced by lead and mobilize the heavy metal such as lead from intra-cellular positions. This review provides therapeutic approaches such as vitamin C, vitamin E, and extract of garlic to treat the detrimental effects caused after the exposure of lead. These therapeutic strategies are beneficial for both the prevention and alleviation of lead noxiousness.

Chitosan from crustacean shell waste and its protective role against lead toxicity in Oreochromis mossambicus

In the current study heavy metal removing capability and antioxidant properties of chitosan supplemented diet tested in lead poisoning induced Oreochromis mossambicus in comparison with and standard fish diet. O. mossambicus fishes weighed (20 ± 2gm) were purchased from a local commercial fish pond and acclimated to the laboratory conditions for 10 days. After that fish were dived into four groups, each group received respective feed throughout the experimental period. The fish fed with standard diet exhibited drastic weakening of superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GR), glutathione peroxidase (GPx), ascorbic acid, α- tocopherol and β-carotene and also displayed abnormal histological changes in gills, liver, and intestine. The fish fed with a chitosan supplemented diet for 10 days showed substantial enhancements in antioxidant levels and also normal histological structures of organs in the fish.

Nickel: Human Health and Environmental Toxicology

Nickel is a transition element extensively distributed in the environment, air, water, and soil. It may derive from natural sources and anthropogenic activity. Although nickel is ubiquitous in the environment, its functional role as a trace element for animals and human beings has not been yet recognized. Environmental pollution from nickel may be due to industry, the use of liquid and solid fuels, as well as municipal and industrial waste. Nickel contact can cause a variety of side effects on human health, such as allergy, cardiovascular and kidney diseases, lung fibrosis, lung and nasal cancer. Although the molecular mechanisms of nickel-induced toxicity are not yet clear, mitochondrial dysfunctions and oxidative stress are thought to have a primary and crucial role in the toxicity of this metal. Recently, researchers, trying to characterize the capability of nickel to induce cancer, have found out that epigenetic alterations induced by nickel exposure can perturb the genome. The purpose of this review is to describe the chemical features of nickel in human beings and the mechanisms of its toxicity. Furthermore, the attention is focused on strategies to remove nickel from the environment, such as phytoremediation and phytomining.

Pharmacological Evidences for Curcumin Neuroprotective Effects against Lead-Induced Neurodegeneration: Possible Role of Akt/GSK3 Signaling Pathway

One of main herbal compounds with neuroprotective effects is curcumin. Lead poisoning cause neurodegeneration effect but its clear mechanism remains unknown. The current study evaluates the role of Akt/GSK3 signaling pathway in mediating the neuroprotective effects of curcumin against lead -induced neurodegeneration in rats. Sixty adult male rats were divided to: Group 1 and 2 receiving normal saline and drinking water containing 0.075% of lead acetate. Groups 3, 4, 5, and 6 were treated concurrently with lead acetate (0.075% in drinking water) and Curcumin (10, 20, 40, and 80 mg/kg I.P, respectively). Morris water maze (MWM) was used to evaluate cognitive activity, Hippocampal oxidative, anti-oxidant, as well as inflammatory and apoptotic factors and also Akt and GSK3 protein levels were studied. We found that lead poisoning disturbed the learning and memory and simultaneous treatment with Curcumin reduced the lead -induced cognition disturbances. In addition, lead acetate treatment increased lipid peroxidation and the levels of IL-1β, TNF-α , Bax, GSK3 (total and phosphorylated) while reducing reduced form of GSH, Bcl-2, and Akt3 (total and phosphorylated) levels in the hippocampus. Lead also reduced the activity of SOD, GPx, and GR in the hippocampus. In contrast, various doses of Curcumin attenuated lead -induced apoptosis, oxidative stress and inflammation; while elevating P-Akt and reduced of GSK3 levels. Thus, Curcumin via mediation of Akt/GSK3 signaling pathway confers neuroprotection against lead-induced neurodegeneration in hippocampus.

The effect of diosmin against lead exposure in rats‡

In this study, the effect of diosmin against the adverse effects of lead exposure in rats was investigated. Wistar Albino race 40 male rats weighing 150-200 g 2-3 months were used. A total of 4 groups were assigned, one of which was control and the other 3 were trial groups. The rats in the control group were treated with dimethyl sulfoxide, which was used only as a vehicle in diosmin administration. Groups 2, 3, and 4 from the experimental group were given diosmin at a dose of 50 mg/kg.bw, lead acetate at the dose of 1000 ppm, lead acetate at the dose of 1000 ppm, and diosmin at a dose of 50 mg/kg.bw for 6 weeks, respectively. Application of lead acetate with drinking water and also diosmin was performed by oral catheter. At the end of the experimental period, blood was taken to dry and with heparin by puncture to the heart under light ether anesthesia. Following the blood samples, some organs of the rats (the liver, kidney, brain, heart, and testis) were removed. Some biochemical parameters (glucose, triglyceride, cholesterol, BUN, creatinine, uric acid, LDH, AST, ALT, ALP, total protein, albumin) were measured in serum. Some oxidative stress parameters in tissue samples and blood (MDA, NO, SOD, CAT, GSH-Px, GSH) were evaluated. Body and organ (the liver, kidney, brain, heart, and testis) weights were also evaluated at the end of the study. No significant change was observed in the parameters examined in the diosmin alone-treated group by comparison to control group. On the other hand, significant changes were found in the values ​​of lead acetate-treated group comparing control group. It was observed that the values approached the values of the control group in the combination of lead and diosmin. Exposure to lead acetate at a dose of 1000 ppm for 6 weeks causes organ damage; however the diosmin application at a dose of 50 mg/kg.bw had a positive effect on the regression of tissue damage.

Hepatorenal protective effect of flaxseed protein isolate incorporated in lemon juice against lead toxicity in rats

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Flaxseed protein isolate (FPI) is a good source of protein with potent antioxidant activity.

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Solubility and scavenging radical activity of FPI increased in the acidic medium.

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Lead intoxication elevated lipid peroxidation of kidney, urinary protein and creatinine as well as kidney and liver functions.

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lemon juice and FPI are considered protective sources of kidney and liver against lead toxicity.

Finding renal and hepatoprotective agents preferably with antioxidant activities against environmental pollutants especially lead which can adversely affect liver and kidney is a great demand. In the current study, flaxseed protein isolate (FPI) was extracted from defatted flaxseed meal. Amino acids profile, antioxidant capacity and solubility of the extracted FPI were determined. The solubility of FPI in the acidic media was exploited in preparation of lemon juice with FPI. Twenty four male rats were assigned to four groups; normal control, lead intoxicated (oral daily dose of 60 mg/kg b.w. in distilled water for four weeks), lead intoxicated and orally administrated with daily dose equal 1 ml of lemon juice as well as lead intoxicated and orally administered with FPI (daily dose equal 100 mg/kg) in 1 ml of lemon juice. The oral administration of FPI incorporated in lemon juice suppressed the elevation in kidney functions, lipid peroxidation of kidney tissues, urinary protein and creatinine as well as liver functions caused by lead intoxication. Additionally, lemon juice with FPI combated the reduction of GSH of kidney tissues. It was revealed also that lemon juice without FPI suppressed the elevation in kidney and liver functions caused by lead. It can be concluded that flaxseed protein isolate is a good source of protein with potent antioxidant activity. Additionally, lemon juice and FPI are considered protective sources of kidney and liver against lead toxicity.

Mechanoregulation of titanium dioxide nanoparticles in cancer therapy

Titanium dioxide (TiO₂) nanoparticles (NPs), first developed in the 1990s, have been applied in numerous biomedical fields such as tissue engineering and therapeutic drug development. In recent years, TiO₂-based drug delivery systems have demonstrated the ability to decrease the risk of tumorigenesis and improve cancer therapy. There is increasing research on the origin and effects of pristine and doped TiO₂-based nanotherapeutic drugs. However, the detailed molecular mechanisms by which drug delivery to cancer cells alters sensing of gene mutations, protein degradation, and metabolite changes as well as its associated cumulative effects that determine the microenvironmental mechanosensitive metabolism have not yet been clearly elucidated. This review focuses on the microenvironmental influence of TiO₂-NPs induced various mechanical stimuli on tumor cells. The differential expression of genome, proteome, and metabolome after treatment with TiO₂-NPs is summarized and discussed. In the tumor microenvironment, mechanosensitive DNA mutations, gene delivery, protein degradation, inflammatory responses, and cell viability affected by the mechanical stimuli of TiO₂-NPs are also examined.

Nasr S. Monitoring of Carcinogenic Environmental Pollutants in raw Cows’ Milk

These investigations were conducted to detect the residues of polycyclic aromatic hydrocarbons, lead, and cadmium in the raw milk samples of lactating cows grazing around the Sugar Cane Factory. One hundred raw milk samples were collected from apparent healthy lactating cows during the rest and work periods of the Sugar Cane Factory. Detection of polycyclic aromatic hydrocarbons residue in milk samples was performed using a gas chromatography. Lead and cadmium levels in the milk samples were determined after digestion. Results revealed that benzo(a)anthracene and indeno(1,2,3-cd)pyrene (carcinogenic), and acenaphthylene and phenanthrene non-carcinogenic were detected only in the raw milk samples during the work period, while fluoranthene and benzo(a)pyrene were detected only during the rest period. However, chrysene and benzo(b) fluoranthene (carcinogenic) were detected in the milk at the rest and work periods of the Sugar Cane Factory. The highest levels of lead and cadmium were detected during the work period compared to the levels of lead and cadmium at rest. In conclusion, benzo(a)anthracene, indeno(1,2,3-cd)pyrene, acenaphthylene, and phenanthrene, lead and cadmium could be detected in cows’ milk which raised around the Sugar Cane Factory. Further investigations of these pollutants must be done in water, plants, air, and soil around this factory.

Toxic Effect of Acute Cadmium and Lead Exposure in Rat Blood, Liver, and Kidney

Background: Cadmium and lead are widespread and non-biodegradable pollutants of great concern to human health. In real life scenarios, we are exposed to mixtures of chemicals rather than single chemicals, and it is therefore of paramount importance to assess their toxicity. In this study, we investigated the toxicity of Cd and Pb alone and as a mixture in an animal model of acute exposure. Methods: Experimental groups received a single treatment of aqueous solution of Cd-chloride (15 and 30 mg/kg body weight (b.w.) and Pb-acetate (150 mg/kg b.w.), while the mixture group received 15 mg Cd/kg b.w. and 150 mg Pb/kg b.w. Toxic effects of individual metals and their mixture were investigated on hematological and biochemical parameters, and the redox status in the plasma, liver, and kidneys of treated Wistar rats. Results: Tissue-specific changes were recorded in various parameters of oxidative damage, while the accumulation of metals in tissues accompanied the disturbances of both hematological and biochemical parameters. It was observed that the level of toxic metals in tissues had a different distribution pattern after mixture and single exposure. Conclusions: Comprehensive observations suggest that exposure to Cd and Pb mixtures produces more pronounced effects compared to the response observed after exposure to single metal solutions. However, further research is needed to confirm toxicokinetic or toxicodynamic interactions between these two toxic metals in the organisms.

Toxicity assessment of ash and dust from handmade gold jewelry manufacturing workshops in Bangladesh

Traditionally, handmade gold jewelry played a very important role in the cultural heritage of Bangladesh. Goldsmiths still are partially using ancient manufacturing process with coal fire, candle flame blowing, and nitric and sulfuric acid treatments. Such process leads to the contamination of workplace with the dust of toxic metals, acidic vapors, and particles of different natures. To evaluate contamination by particulate matter (PM), the passive particle collectors were installed in different manufacturing units for a period of 85 days at Tanti Bazar, Dhaka, Bangladesh. The laser diffraction analysis of the samples collected at the soldering units showed significant amounts of particulates, both PM10 and PM 2.5, and also nanoparticles in both nucleation and accumulation mode. SEM/EDS analysis revealed partially melted micro blebs that contain a very high concentration of Fe along with Cu. The toxic elements were detected with ICP analysis and include higher concentrations of cadmium (Cd), chromium (Cr), lead (Pb), and arsenic (As). It is notable that detection of arsenic contamination was unexpected since raw materials used for jewelry making should not have any arsenic.

Mercury Exposure and Heart Diseases

Environmental contamination has exposed humans to various metal agents, including mercury. It has been determined that mercury is not only harmful to the health of vulnerable populations such as pregnant women and children, but is also toxic to ordinary adults in various ways. For many years, mercury was used in a wide variety of human activities. Nowadays, the exposure to this metal from both natural and artificial sources is significantly increasing. Recent studies suggest that chronic exposure, even to low concentration levels of mercury, can cause cardiovascular, reproductive, and developmental toxicity, neurotoxicity, nephrotoxicity, immunotoxicity, and carcinogenicity. Possible biological effects of mercury, including the relationship between mercury toxicity and diseases of the cardiovascular system, such as hypertension, coronary heart disease, and myocardial infarction, are being studied. As heart rhythm and function are under autonomic nervous system control, it has been hypothesized that the neurotoxic effects of mercury might also impact cardiac autonomic function. Mercury exposure could have a long-lasting effect on cardiac parasympathetic activity and some evidence has shown that mercury exposure might affect heart rate variability, particularly early exposures in children. The mechanism by which mercury produces toxic effects on the cardiovascular system is not fully elucidated, but this mechanism is believed to involve an increase in oxidative stress. The exposure to mercury increases the production of free radicals, potentially because of the role of mercury in the Fenton reaction and a reduction in the activity of antioxidant enzymes, such as glutathione peroxidase. In this review we report an overview on the toxicity of mercury and focus our attention on the toxic effects on the cardiovascular system.