Protective effects of zinc in chlorpyrifos induced hepatotoxicity: a biochemical and trace elemental study

Clinical and biochemical understanding of Zinc interaction during liver diseases: A paradigm shift

Zinc (Zn) is an essential and the second most abundant trace element after Iron. It can apply antioxidant, anti-inflammatory, and anti-apoptotic activity. It is assumed to be indispensable for cell division, cellular differentiation and cell signalling. Zinc is essential for proper liver function which is also the site of its metabolism. Depleted Zn concentrations have been observed in both acute and chronic hepatic diseases. It is reported that Zn deficiency or abnormal Zn metabolism during majority of liver diseases is attributed to deficient dietary intake of Zn, augmented disposal of Zn in the urine, activation of certain Zn transporters, and expression of hepatic metallothionein. Undoubtedly, Zn is involved in generating many diseases but how and whether it plays role from acute to fulminant stage of all chronic liver diseases remains to be cleared. Here, we will discuss the role of Zn in development of different diseases specifically the involvement of Zn to understand the aetiology and intricate mechanism of dynamic liver diseases.

Feed Composition Differences Resulting from Organic and Conventional Farming Practices Affect Physiological Parameters in Wistar Rats-Results from a Factorial, Two-Generation Dietary Intervention Trial

Recent human cohort studies reported positive associations between organic food consumption and a lower incidence of obesity, cancer, and several other diseases. However, there are very few animal and human dietary intervention studies that provide supporting evidence or a mechanistic understanding of these associations. Here we report results from a two-generation, dietary intervention study with male Wistar rats to identify the effects of feeds made from organic and conventional crops on growth, hormonal, and immune system parameters that are known to affect the risk of a number of chronic, non-communicable diseases in animals and humans. A 2 × 2 factorial design was used to separate the effects of contrasting crop protection methods (use or non-use of synthetic chemical pesticides) and fertilizers (mineral nitrogen, phosphorus and potassium (NPK) fertilizers vs. manure use) applied in conventional and organic crop production. Conventional, pesticide-based crop protection resulted in significantly lower fiber, polyphenol, flavonoid, and lutein, but higher lipid, aldicarb, and diquat concentrations in animal feeds. Conventional, mineral NPK-based fertilization resulted in significantly lower polyphenol, but higher cadmium and protein concentrations in feeds. Feed composition differences resulting from the use of pesticides and/or mineral NPK-fertilizer had a significant effect on feed intake, weight gain, plasma hormone, and immunoglobulin concentrations, and lymphocyte proliferation in both generations of rats and in the second generation also on the body weight at weaning. Results suggest that relatively small changes in dietary intakes of (a) protein, lipids, and fiber, (b) toxic and/or endocrine-disrupting pesticides and metals, and (c) polyphenols and other antioxidants (resulting from pesticide and/or mineral NPK-fertilizer use) had complex and often interactive effects on endocrine, immune systems and growth parameters in rats. However, the physiological responses to contrasting feed composition/intake profiles differed substantially between the first and second generations of rats. This may indicate epigenetic programming and/or the generation of "adaptive" phenotypes and should be investigated further.

Does the perigestational exposure to chlorpyrifos and/or high-fat diet affect respiratory parameters and diaphragmatic muscle contractility in young rats?

The perinatal period is characterized by developmental stages with high sensitivity to environmental factors. Among the risk factors, maternal High-Fat Diet (HFD) consumption and early-life pesticide exposure can induce metabolic disorders at adulthood. We established the effects of perigestational exposure to Chlorpyrifos (CPF) and/or HFD on respiratory parameters, sleep apnea and diaphragm contractility in adult rats. Four groups of female rats were exposed starting from 4 months before gestation till the end of lactation period to CPF (1 mg/kg/day vs. vehicle) with or without HFD. Sleep apnea and respiratory parameters were measured by whole-body plethysmography in male offspring at postnatal day 60. Then diaphragm strips were dissected for the measurement of contractility, acetylcholinesterase (AChE) activity, and gene expression. The perigestational exposure to CPF and/or HFD increased the sleep apnea index but decreased the respiratory frequency. The twitch tension and the fatigability index were also increased, associated with reduced AChE activity and elevated mRNA expression of AChE, ryanodine receptor, and myosin heavy chain isoforms. Therefore, the perigestational exposure to either CPF and/or HFD could program the risks for altered ventilatory parameters and diaphragm contractility in young adult offspring despite the lack of direct contact to CPF and/or HFD.

Organophosphorus pesticides can influence the development of obesity and type 2 diabetes with concomitant metabolic changes

Widespread use and the bioaccumulation of pesticides in the environment lead to the contamination of air, water, soil and agricultural resources. A huge body of evidence points to the association between the pesticide exposure and increase in the incidence of chronic diseases, e.g. cancer, birth defects, reproductive disorders, neurodegenerative, cardiovascular and respiratory diseases, developmental disorders, metabolic disorders, chronic renal disorders or autoimmune diseases. Organophosphorus compounds are among the most widely used pesticides. A growing body of evidence is suggesting the potential interdependence between the organophosphorus pesticides (OPs) exposure and risk of obesity and type 2 diabetes mellitus (T2DM). This article reviews the current literature to highlight the latest in vitro and in vivo evidences on the possible influence of OPs on obesity and T2DM development, as well as epidemiological evidence for the metabolic toxicity of OPs in humans. The article also draws attention to the influence of maternal OPs exposure on offspring. Summarized studies suggest that OPs exposure is associated with metabolic changes linked with obesity and T2DM indicated that such exposures may increase risk or vulnerability to other contributory components.

Effects of zinc supplementation on oxidant/antioxidant and lipids status of pesticides sprayers

Background

Excess exposure to pesticides induces oxidative stress and causes alteration in the lipid profile

Objectives

The study aimed to evaluate the effects of Zinc (Zn) supplementation on the oxidant/antioxidant and lipid status in pesticide sprayers.

Methods

Forty pesticide sprayers were included in the study. Blood lipids, malondialdehyde (MDA), glutathione peroxidase (GPx), superoxide dismutase (SOD), and Zn were estimated; before and after Zn supplementation.

Results

Statistical analysis revealed that after Zn supplementation, total cholesterol (TC), triglycerides (TG), low density lipoprotein (LDL), very low density lipoprotein (VLDL), and MDA were significantly decreased. However, there was a significant increase in the high density lipoprotein (HDL), SOD, GPx, and Zn levels. After Zn supplementation, significant inverse correlations were detected between the Zn and the levels of MDA, TG, and VLDL, while positive correlation between Zn and the levels of HDL and TC.

Conclusions

Zn supplementation improves the oxidative/antioxidants and lipid status in pesticide sprayers.

Assessment of neurohepatic DNA damage in male Sprague-Dawley rats exposed to organophosphates and pyrethroid insecticides

The current work was undertaken to test the genotoxic potential of chlorpyrifos (CPF), dimethoate, and lambda cyhalothrin (LCT) insecticides in rat brain and liver using the single cell gel electrophoresis (comet assay). Three groups of adult male Sprague-Dawley rats were exposed orally to one third LD₅₀of CPF, dimethoate, or LCT for 24 and 48 h while the control group received corn oil. Serum samples were collected for estimation of malondialdehyde (MDA) and glutathione peroxidase (GPx); the brain and liver samples were used for comet assay and for histopathological examination. Results showed that signs of neurotoxicity appeared clinically as backward stretching of hind limb and splayed gait in dimethoate and LCT groups, respectively. CPF, LCT, and dimethoate induced oxidative stress indicated by increased MDA and decreased GPx levels. CPF and LCT caused severe DNA damage in the brain and liver at 24 and 48 h indicated by increased percentage of DNA in tail, tail length, tail moment, and olive tail moment. Dimethoate induced mild DNA damage in the brain and liver at 48 h. Histopathological changes were observed in the cerebrum, cerebellum, and liver of exposed rats. The results concluded that CPF, LCT, and dimethoate insecticides induced oxidative stress and DNA damage associated with histological changes in the brain and liver of exposed rats.

Alpha lipoic acid protects against chlorpyrifos-induced toxicity in Wistar rats via modulating the apoptotic pathway

The chronic exposure to chlorpyrifos (CPF) pesticide induces several human disorders including hepatotoxicity. Alpha-lipoic acid (ALA) is a natural antioxidant compound found in plants and animals. The present study aimed to investigate the possible protective effect of ALA against CPF-induced hepatotoxicity and the possible underlying molecular mechanism. Thirty-two male Wistar rats were divided into: Normal rats received only vehicle; ALA group received ALA (10 mg/kg, i.p.); CPF group received CPF (18 mg/kg, s.c.) and CPF-ALA group received CPF (18 mg/kg, s.c.) once daily for 14 days. The present results demonstrated that administration of ALA significantly improved liver functions (p < 0.05) and limited the histopathological lesions induced by CPF in liver tissues. Furthermore, ALA decreased hepatic malondialdehyde contents while increased the glutathione peroxidase, catalase, superoxide dismutase and acetylcholinesterase activities. Interestingly, ALA showed significant antiapoptotic effects through downregulation of Bax and Caspase-3 expression levels. In conclusion, ALA possess protective effects against CPF-induced liver injury through attenuation of apoptosis and oxidative stress.

Adverse effects of organophosphorus pesticides on the liver: a brief summary of four decades of research

Organophosphorus pesticides (OPs) are widely used volatile pesticides that have harmful effects on the liver in acute and chronic exposures. This review article summarises and discusses a wide collection of studies published over the last 40 years reporting on the effects of OPs on the liver, in an attempt to propose general mechanisms of OP hepatotoxicity and possible treatment. Several key biological processes have been reported as involved in OP-induced hepatotoxicity such as disturbances in the antioxidant defence system, oxidative stress, apoptosis, and mitochondrial and microsomal metabolism. Most studies show that antioxidants can attenuate oxidative stress and the consequent changes in liver function. However, few studies have examined the relationship between OP structures and the severity and mechanism of their action. We hope that future in vitro, in vivo, and clinical trials will answer the remaining questions about the mechanisms of OP hepatotoxicity and its management.

Understanding the role of 3-O-Acetyl-11-keto-β-boswellic acid in conditions of oxidative-stress mediated hepatic dysfunction during benzo(a)pyrene induced toxicity

The present study was planned to see whether 3-O-Acetyl-11- keto-β-boswellic acid has any protective effects against benzo(a)pyrene (BaP) induced toxicity or not. In vitro studies show concentration dependent linear association of radical scavenging activity of AK which is comparable to ascorbic acid taken as reference compound. For in vivo studies, the animals were divided randomly into five groups which included a) normal control, b) vehicle treated (olive oil), c) BaP treated, d) AK treated and e) AK + BaP (combined treated). BaP was administered at a dose of 50mg/kg in olive oil twice a week orally for 4 weeks and AK (50mg/kg) was given in olive oil thrice a week for 4 weeks before and after BaP exposure. BaP treated animals showed a significant increase (p < 0.001) in lipid peroxidation (LPO) and protein carbonyl contents (PCC) in hepatic tissue. Further, a significant increase (p < 0.001) in the liver marker enzymes as well as citrulline and nitric oxide levels in the hepatic tissue was also observed. Interestingly, AK when supplemented to BaP treated animals ameliorated the above said biochemical indices appreciately. The histopathological observations also showed appreciable improvement when BaP treated animals were supplemented with AK, thus emphasing the protective potential of AK.

Hepatotoxicity and nephrotoxicity induced by the chlorpyrifos and chlorpyrifos-methyl metabolite, 3,5,6-trichloro-2-pyridinol, in orally exposed mice

3,5,6-Trichloro-2-pyridinol (TCP) is a primary degradation product of chlorpyrifos and chlorpyrifos-methyl. TCP has longer half-life in soil and greater solubility in water than its parent compound, and cause wide contamination in environments. However, studies about the toxic effects of TCP are limited and outdate. In this study, 5 mg/kg/day, 50 mg/kg/day, and 150 mg/kg/day TCP were given to male mice through gavage for four weeks. As a result, the final body weights of TCP treated groups were significantly lower than control, and the relative organ weights of the liver and kidney were significantly higher than that of control. In addition, NMR-based metabolomics was used to investigate the toxic effects of TCP. It was found that a total of 39 serum metabolites were significantly changed in the TCP-treated groups, and these metabolites are related to hepatotoxicity and nephrotoxicity. These results were also confirmed by histopathology, serum biochemical, and oxidative stress analysis. In addition, metabolic disturbances due to TCP exposure were also observed based on altered metabolites. As far as we know, these results are the first to show the metabolomic toxicity of TCP, which warrants further research.

Pesticide chlorpyrifos acts as an endocrine disruptor in adult rats causing changes in mammary gland and hormonal balance

Endocrine disruptors (EDs) are compounds that interfere with hormone regulation and influence mammary carcinogenesis. We have previously demonstrated that the pesticide chlorpyrifos (CPF) acts as an ED in vitro, since it induces human breast cancer cells proliferation through estrogen receptor alpha (ERα) pathway. In this work, we studied the effects of CPF at environmental doses (0.01 and 1mg/kg/day) on mammary gland, steroid hormone receptors expression and serum steroid hormone levels. It was carried out using female Sprague-Dawley 40-days-old rats exposed to the pesticide during 100 days. We observed a proliferating ductal network with a higher number of ducts and alveolar structures. We also found an increased number of benign breast diseases, such as hyperplasia and adenosis. CPF enhanced progesterone receptor (PgR) along with the proliferating cell nuclear antigen (PCNA) in epithelial ductal cells. On the other hand, the pesticide reduced the expression of co-repressors of estrogen receptor activity REA and SMRT and it decreased serum estradiol (E2), progesterone (Pg) and luteinizing hormone (LH) levels. Finally, we found a persistent decrease in LH levels among ovariectomized rats exposed to CPF. Therefore, CPF alters the endocrine balance acting as an ED in vivo. These findings warn about the harmful effects that CPF exerts on mammary gland, suggesting that this compound may act as a risk factor for breast cancer.

Zinc Improves Cognitive and Neuronal Dysfunction During Aluminium-Induced Neurodegeneration

Metals are considered as important components of a physiologically active cell, and imbalance in their levels can lead to various diseased conditions. Aluminium (Al) is an environmental neurotoxicant, which is etiologically related to several neurodegenerative disorders like Alzheimer's, whereas zinc (Zn) is an essential trace element that regulates a large number of metabolic processes in the brain. The objective of the present study was to understand whether Zn provides any physiological protection during Al-induced neurodegeneration. Male Sprague Dawley rats weighing 140-160 g received either aluminium chloride (AlCl₃) orally (100 mg/kg b.wt./day), zinc sulphate (ZnSO₄) in drinking water (227 mg/L) or combined treatment of aluminium and zinc for 8 weeks. Al treatment resulted in a significant decline in the cognitive behaviour of rats, whereas zinc supplementation caused an improvement in various neurobehavior parameters. Further, Al exposure decreased (p ≤ 0.001) the levels of neurotransmitters, acetylcholinesterase activity, but increased (p ≤ 0.001) the levels of L-citrulline as well as activities of nitric oxide and monoamine oxidase in the brain. However, zinc administration to Al-treated animals increased the levels of neurotransmitters and regulated the altered activities of brain markers. Western blot of tau, amyloid precursor protein (APP), glial fibrillary acidic protein (GFAP), ubiquitin, α-synuclein and Hsp 70 were also found to be elevated after Al exposure, which however were reversed following Zn treatment. Al treatment also revealed alterations in neurohistoarchitecture in the form of loss of pyramidal and Purkinje cells, which were improved upon zinc co-administration. Therefore, the present study demonstrates that zinc improves cognitive functions by regulating α-synuclein and APP-mediated molecular pathways during aluminium-induced neurodegeneration.

Radioprotective agents for the prevention of side effects induced by radioiodine-131 therapy

Radioiodine 131 (131I) has been used worldwide for the ablation of remnant thyroidal tissue after surgery or as the first-line treatment for Graves’ disease. Although the use of 131I is becoming increasingly prevalent, there is evidence suggesting that this treatment is associated with side effects such as salivary gland dysfunction and an increased risk of leukemia. This article aims to review the potential use of radioprotective agents and the side effects induced by 131I therapy. Several synthetic and natural compounds have been investigated in preclinical and clinical studies. The protective agents reduced the toxicity of 131I, mainly in the salivary glands, and mitigated the genetic damage through different mechanisms. There are limited clinical studies evaluating the use of radioprotective agents in patients undergoing radioiodine therapy. However, lemon candies, lemon juice and sugarless chewing gum have been proposed to be beneficial for minimizing the side effects of radioiodine within the salivary glands.

Characterization of the interaction between cadmium and chlorpyrifos with integrative techniques in incurring synergistic hepatoxicity

Mixture toxicity is an important issue for the risk assessment of environmental pollutants, for which an extensive amount of data are necessary in evaluating their potential adverse health effects. However, it is very hard to decipher the interaction between compounds due to limited techniques. Contamination of heavy metals and organophosphoric insecticides under the environmental and biological settings poses substantial health risk to humans. Although previous studies demonstrated the co-occurrence of cadmium (Cd) and chlorpyrifos (CPF) in environmental medium and food chains, their interaction and potentially synergistic toxicity remain elusive thus far. Here we integrated the approaches of thin-layer chromatography and (1)H NMR to study the interaction between Cd(2+) and CPF in inducing hepatoxicity. A novel interaction was identified between Cd(2+) and CPF, which might be the bonding between Cd(2+) and nitrogen atom in the pyridine ring of CPF, or the chelation formation between one Cd(2+) and two CPF molecules. The Cd-CPF complex was conferred with distinct biological fate and toxicological performances from its parental components. We further demonstrated that the joint hepatoxicity of Cd ion and CPF was chiefly due to the Cd-CPF complex-facilitated intracellular transport associated with oxidative stress.

Sub-chronic exposure to chlorpyrifos induces hematological, metabolic disorders and oxidative stress in rat: attenuation by glutathione

The current work aimed to investigate the different toxic effects of chlorpyrifos (CPF) in subchronic exposure. Two groups of Sprague-Dawley male rats were exposed to CPF alone in a dose of 30 mg/kg body weight, or CPF dose as previous plus glutathione (GSH) in a dose of 100 mg/kg body weight, for 90 days, twice weekly, orally. Another two groups of rat were given corn oil (control) or GSH. There is a significant decrease in hemoglobin concentration, haematocrit percentage, thrombocytic indices, total protein and albumin levels in CPF-exposed group. CPF induced hyperglycemia and significant increase in total cholesterol, but a significant decrease in triglyceride levels was obtained. A significant increase in the levels of lipid peroxidation was obtained while a significant decrease of the total antioxidant was recorded. The decrease in glycogen content and some histopathological changes were observed in liver after CPF exposure. Furthermore, co-administration of GSH can restore some of these alterations.

Effectiveness of Zinc in Modulating the CCl (4) - Induced Oxidative Stress in Rat Liver

The present study was designed to evaluate the role of zinc on the enzymes involved in oxidative defense mechanism in conditions of carbon tetrachloride (CCl (4)) -induced rat liver toxicity. To carry out the study, rats were divided into four groups: group I (normal control), group II (CCl (4) treated), group III (zinc control), and group IV (zinc + CCl (4) treated). Animals in group II and group IV were administered 0.1 mL of CCl (4) mixed with 0.1 mL of groundnut oil on alternate days for a period of 8 weeks. Zinc in the form of zinc sulphate was given to animals of group II and group IV at a dose level of 227 mg/L in drinking water. Animals given CCl (4) treatment alone showed a significant increase in the activities of superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx), and the concentration of malondialdehyde (MDA) product, whereas a significant depression was observed in the levels of reduced glutathione (GSH). Zinc treatment to CCl (4) -treated rats brought the altered levels of GSH, MDA, and SOD as observed following CCl (4) -treatment alone to within normal limits. However, the activities of catalase and glutathione peroxidase, which were increased under carbon tetrachloride treatment, were significantly attenuated and tended to become normal. Hence, the present study suggests that zinc may play an important role in regulating the activities of the enzymes involved in antioxidative defense system under CCl (4) toxic conditions.

Pathological effects of dichlorvos and fenitrothion in mice

Seeds of faba and soybeans were treated with dichlorvos (12 mg/kg) and fenitrothion (5 mg/kg) insecticides and stored for 30 weeks. The total internal residues of dichlorvos and fenitrothion amounted to about 69%, 73% and 67%, 74% in the applied doses in faba and soybeans, respectively. The pathological potential of dichlorvos and fenitrothion residues was studied by feeding mice for 90 days with the treated seeds. Parallel studies were conducted in two control groups. Liver and kidney were taken for histological examinations. The results of blood biochemistry are supported by the histopathological changes observed in the liver and kidney of treated mice. Dichlorvos and fenitrothion insecticides caused degenerative changes in the liver and kidney of mice. Changes were more intense in mice which were given beans treated with dichlorvos than in mice fed on beans treated with fenitrothion. The livers of both treated groups showed an abnormal size and shape of hepatic cells. The kidneys of treated mice showed tubular vascular degeneration and lumen dilatation in both groups as compared with the control group.

Accumulation levels and characteristics of some pesticides in human adipose tissue samples from Southeast China

This paper presents a comprehensive study of pesticide levels and bio-accumulation characteristics in human adipose tissues among residents of Southeast China. A large number of adipose samples (n=633) were selected for 58 pesticides and were analyzed by high sensitive Gas Chromatography-Tandem Mass Spectrometry (GC-MS/MS). The results showed that POPs pesticides were frequently detected, including 2,4'-DDD, 2,4'-DDE, 2,4'-DDT, 4,4'-DDD, 4,4'-DDE, 4,4'-DDT, α-HCH, β-HCH, γ-HCH, δ-HCH, hexachlorobenzene (HCB), and mirex. Other detected pesticide species were dicofol, methamidophos and chlordimeform, which have rarely been reported. Comparing to different countries, the concentrations of total DDT and HCH in these three Chinese southeastern sites were in the middle range, whereas the HCB and mirex were in the lower end. A significant correlation was observed between region as well as age and POPs pesticide levels. Some pesticide residue levels were also found significantly correlated to occupation. However, there was no significant correlation between gender and pesticides. Meanwhile, it is interesting to find that mortality of malignant tumors tends to associate with the pesticides levels in human adipose tissue. More importantly, the measured data presented in this study provide realistic information which is useful for assessing human exposure to pesticides in the general population of Southeast China.

Effect of different dietary zinc levels on hepatic antioxidant and micronutrients indices under oxidative stress conditions

Dietary zinc (Zn) status exerts a powerful influence on the degree of oxidative damage caused by free radicals. We examined the effect of dietary Zn variations with oxidative stress (OS) treatment on antioxidant status, liver function, and status of vitamins in male Wistar rats. Oxidative stress was generated by intraperitoneal injections of tert-butyl hydroperoxide; and dietary Zn variations done were Zn deficient, normal, and excess, with 8, 30, and 60 mg Zn per kilogram diet, respectively. After 21-day dietary regimen, the animals were killed; and plasma aspartate aminotransferase, alanine aminotransferase, hepatic antioxidant enzymes (catalase, superoxide dismutase, glutathione peroxidase), Zn, reduced glutathione, lipid peroxidation (LPO), and hepatic riboflavin, nicotinic acid, and ascorbic acid estimations were done. The alanine aminotransferase and aspartate aminotransferase levels were elevated in rats with OS and Zn-deficient diet, which were restored to normal levels with excess dietary Zn. Hepatic antioxidant enzymes and reduced glutathione levels were significantly decreased with concomitant increase in LPO due to OS induction in animals with Zn-deficient diet. Corresponding enhanced enzyme activities, higher hepatic Zn, and lowered LPO were observed in animals with normal- and excess-Zn diet. A dose-dependent increase in hepatic nicotinic acid accumulation was observed as the dietary Zn level increased from deficient to excess; however, there was no influence on riboflavin and ascorbic acid status. The results suggest that Zn may have a therapeutic potential in treatment of oxidative liver damage along with enhanced nicotinic acid absorption.

Monitoring health implications of pesticide exposure in factory workers in Pakistan

The study aimed to determine the hazardous health effects of pesticides exposure in the factory workers by measuring plasma cholinesterase (PChE), pesticides residues, and renal and hepatic biochemical markers. In addition, we also assessed the knowledge, attitudes, and safety practices adopted by the industrial workers. The study was conducted in three different sizes of factories located in Lahore (large), Multan (medium), and Karachi (small) in Pakistan. Total 238 adult males consisting of 184 pesticide industrial workers (exposed group) from large-sized (67), medium-sized (61), small-sized (56) industrial formulation factories, and 54 controls (unexposed) were included in the study. All the participants were male of aged 18 to 58 years. PChE levels were estimated by Ellmann's method. Plasma pesticides residue analysis was performed by using reverse phase C-18 on high-performance liquid chromatograph and GC with NPD detector. Plasma alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatinine, urea, and gamma glutamyltransferase (GGT) were measured on Selectra E auto analyzer. Plasma and C-reactive protein was analyzed by Immulite 1000. The results revealed a significant decrease in plasma post exposure PChE levels (<30%) as compared to baseline in the workers of small (29%) and medium (8%) industrial units (p < 0.001). Plasma cypermethrin, endosulfan, imidacloprid, thiodicarb, carbofuran, and methamidophos levels were found to be higher than allowable daily intake. Serum AST, ALT, creatinine GGT, malondialdehyde, total antioxidant, and CRP were significantly raised among the workers of small and medium pesticide formulation factories as compared to large industrial unit and controls (p < 0.001). The study demonstrated that unsafe practices among small- and medium-sized pesticides industrial workers cause significant increase in pesticide exposure, oxidative stress, and derangement of hepatic and renal function.

Uptake and retention of 65Zn in lithium-treated rat liver: role of zinc

AIM

To evaluate the effects of zinc on the biokinetics of (65)Zn in rat and its distribution in various organs and in subcellular compartment following lithium therapy.

METHODS

Female wistar rats received either lithium treatment at a dose of 1.1g/kg in diet, zinc alone at a dose of 227 mg/L in drinking water, and combined lithium plus zinc for duration of four months.

RESULTS

After four months of lithium treatment, liver enzymes increased significantly (glutamic oxaloacetic transaminase, +66.73%; glutamic pyruvic transaminase, +63.70%; alkaline phosphatase, +40.28%; p< or =0.001); zinc supplementation to lithium-treated rats significantly reduced liver enzymes (glutamic oxaloacetic transaminase, -13.11%; glutamic pyruvic transaminase, -21.78%; alkaline phosphatase, -11.77%; p< or =0.001). The biological half-lives of (65)Zn showed an initial fast component (Tb(1)) and a slower component (Tb(2)). A significant increase in Tb(2) (38.82%, p< or =0.001) in liver was observed following lithium treatment, which significantly decreased following zinc treatment (21.71%, p< or =0.001). A significant decrease in the uptake of (65)Zn (53.93%, p< or =0.01) in liver was observed and in nuclear (p< or =0.01), mitochondrial (p< or =0.01), and microsomal (52.67%, p< or =0.001) fractions. A significant increase in the uptake of (65)Zn (82.92%, p< or =0.05) in liver microsomal fraction (34.09%, p< or =0.001) was observed in lithium-treated rats receiving zinc supplementation.

CONCLUSION

The study suggests that zinc has the potential to regulate the biokinetics of (65)Zn and its subcellular distribution in rat liver following lithium therapy.

Biosafety of flavonoids in rats: effects on copper and zinc homeostasis and interaction with low-level pesticide exposure

Two 30-day experiments (36 male Sprague-Dawley rats each) were conducted to determine effect of administering flavonoid mixture (FM) with concomitant exposure to a pesticide mixture (PM) or FM at varied levels on changes in concentrations of zinc and copper in tissues. In experiment 1, PM = chlorpyrifos, endosulfan, and thiram at 25% LD(50) was dissolved in soybean (SB) oil and gavage-fed 0.1 mL 5 days/week; FM in SB oil was mixed in AIN-93M diet at 1.0 and 5.0 mM/kg diet and fed ad libitum. The groups were Control (CON), PM, FM1, FM5, PM+FM1, and PM+FM5. In experiment 2, FM in 1% polyethylene glycol was gavage-fed (0.5 mL/5 days/week), at increasing levels(mg/kg body weight); the groups were CON, FM5, FM25, FM50, FM100, and FM200. In experiment 1, PM plus FM increased tissue Cu as compared to the CON by: plasma, 16-37%; liver, 9-20%; kidney, 13-41%; small intestinal mucosa (IM), 41%; and small intestines (SI), 77%. In experiment 2, FM fed at higher levels decreased tissue Cu by: plasma, 22-36%; liver, 23%; kidney, 24-44%; IM, 17-26%; and SI, 58% and 77%, as compared to respective CON. Kidney zinc increased at higher concentrations of FM by 14-34%. These results indicate that flavonoids can modify copper homeostasis depending on whether they are fed in the diet or by gavage.

Hepatoprotective Role of Zinc in Lead-Treated, Protein-Deficient Rats

The current study was designed to evaluate the hepatoprotective role of zinc after lead (Pb) treatment of protein-deficient (PD) rats. The animals were subjected to seven different treatment groups: G-1 (normal control, 18% protein), G-2 (protein-deficient, 8% protein), G-3 (Pb-treated, 100 mg/kg body weight of lead acetate), G-4 (Zn-treated, zinc sulfate at a dose level of 227 mg/L drinking water), G-5 (PD + Pb-treated), G-6 (PD + Zn-treated), and G-7 (PD + Pb + Zn-treated). Serum albumin levels and total serum protein contents were estimated to assess the severity of protein deficiency at the end of 8 weeks in all the treatment groups. Also, the study explored the role of zinc on antioxidative defense system enzymes in liver of protein-deficient rats subjected to lead toxicity treatment. Further, the study was extended to elucidate the levels of zinc and lead in liver tissue after different treatments of rats using positron-induced X-ray emission technique (PIXE). The current study indicated a significant change in the levels of various antioxidative enzymes and serum albumin as well as total protein contents of protein-deficient rats subjected to lead treatment. A significant increase in the levels of malondialdehyde (MDA), catalase, and glutathione peroxidase (GPx) was seen after 8 weeks of lead treatment of protein-deficient rats. On the contrary, levels of albumin, total protein content, superoxide dismutase (SOD), GSH, were found to be decreased. Interestingly, zinc supplementation has tended to normalize the altered levels of these enzymes to a significant extent. The levels of zinc in liver tissue was found to be decreased significantly in protein-deficient as well as lead-treated rats. However, hepatic zinc concentration was increased to a significant extent in protein-deficient rats supplemented with zinc when compared with protein-deficient rats. Further, the presence of lead was also observed in livers of lead-treated animals. In conclusion, the study revealed the antioxidative role of zinc in hepatotoxic conditions induced by subjecting the rats to protein-deficient diet and lead treatment.

Role of zinc in mitigating the toxic effects of chlorpyrifos on hematological alterations and electron microscopic observations in rat blood

The present study determined the protective potential of zinc in attenuating the toxicity induced by chlorpyrifos in rat blood. Male Sparque Dawley (SD) rats received either oral chlorpyrifos (13.5 mg/kg body weight) treatment every alternate day, zinc alone (227 mg/l in drinking water) or combined chlorpyrifos plus zinc treatment for a total duration of 8 weeks. The effects of different treatments were studied on various parameters in rat blood including haemoglobin (Hb) levels, total leukocyte count (TLC), differential leukocyte count (DLC), zinc protoporphyrins (ZPP), serum trace elemental concentrations and Scanning Electron Microscopic (SEM) observation of the blood cells. Chlorpyrifos treatment to normal control animals resulted in a significant decrease in TLC and ZPP concentration after 4 and 8 weeks. Chlorpyrifos treated animals also showed significant neutrophilia and lymphopenia after 8 weeks of toxicity. In addition, a significant decrease in serum zinc and iron concentrations were observed following chlorpyrifos intoxication, however, these animals responded with increased serum copper levels following the toxic treatment with this organophosphate. SEM studies of the red blood cells from chlorpyrifos treated animals indicated marked alterations in the topographical morphology of the various cell types, with the prominent feature being common aniscocytosis of the erythrocytes. Oral zinc treatment to the chlorpyrifos treated animals significantly improved the total leukocyte, neutrophil and lymphocyte counts, as well as the otherwise reduced concentrations of ZPP and the levels of various serum trace elements. Protective effects of zinc were also evident in the electron microscopic observations where most blood cell types depicted reverted to a close to the normal appearance. Based upon these data, the present study is first of its kind and suggests that zinc treatment considerably attenuates chlorpyrifos induced toxicity induced in restoring the altered hematological indices and morphological changes.

Effect of pesticide residues on health and different enzyme levels in the blood of farm workers from Gadap (rural area) Karachi-Pakistan

Persons from 14 different fruit and vegetable farm stations from Gadap (rural area), Karachi-Pakistan were examined for the presence of pesticide (cypermethrin, deltamethrin, polytrin-C, diazinon, monocrotophos, DDT and DDE) residues in their blood samples. The present study is concerned with effects of residue on the enzyme levels (GPT, GOT and ALP) as well as the health hazards of pesticide exposed persons. There is a significant increased in the enzyme levels at different stations. Exposed persons complained about liver and kidney dysfunctions and RTI. It may be concluded that exposure of multiple pesticides for prolonged period has affected the normal functioning of different organ systems and possibly produced characteristics clinical effects such as hepatitis, dyspnea and burning sensation in urine.

Chlorpyrifos-induced alterations in the activities of carbohydrate metabolizing enzymes in rat liver: The role of zinc

The present study was conducted to evaluate the adverse effects of chlorpyrifos on the key enzymes of carbohydrate metabolism in liver, and also to assess the role of zinc under these toxic conditions. Male Sprague-Dawley (SD) rats received either oral chlorpyrifos treatment (13.5 mg/kg body weight in corn oil) every alternate day, zinc alone (227 mg/l in drinking water), or combined chlorpyrifos and zinc treatments for a total duration of 8 weeks. The effects of different treatment regimens were studied on various enzymes of carbohydrate metabolism in the rat livers, which included hexokinase, glucose-6-phosphatase, fructose-1,6-diphosphatase, glycogen phosphorylase, succinate dehydrogenase (SDH), lactate dehydrogenase (LDH) and the levels of glycogen. In vitro uptake of (14)C-D-glucose was also assessed in liver slices after similar treatments. Chlorpyrifos intoxication resulted in a significant increase in the activities of glucose-6-phosphatase and glycogen phosphorylase, whereas, it caused a significant inhibition in the levels of hexokinase, SDH, LDH and glycogen content. However, zinc treatment to chlorpyrifos-intoxicated animals was able to normalize the activities of most of these enzymes to either close to, or within normal limits. Chlorpyrifos intoxication demonstrated significantly inhibited (14)C-D-glucose uptake in liver slices, which again was reversed to normal limits following simultaneous zinc treatment. Levels of metallothionein were also found to be depressed in chlorpyrifos-treated animals, but tended to increase significantly on co-administration of zinc to chlorpyrifos-treated group. Hence, the present study clearly suggests that zinc plays an important role in regulating the hepatic activities of the enzymes involved in carbohydrate metabolism under conditions of chlorpyrifos toxicity.

Boron ameliorates fulminant hepatic failure by counteracting the changes associated with the oxidative stress

Boron has well-defined biological effects and may be of therapeutic benefit. In the current paper, the effect of boron in the form of borax was tested in experimental animal model of fulminant hepatic failure (FHF). The syndrome was induced in female Wistar rats by three consecutive daily intraperitoneal injections of thioacetamide (400 mg/kg). In the treatment groups, rats received borax (4.0 mg/kg) orally for three consecutive days followed by thioacetamide. The group administered with thioacetamide plus vehicle, and the borax alone treated rats served as controls. In all groups, rats were terminated 4 h after administering the last dose of thioacetamide, and the tissue/serum was used to measure hepatic levels of thiobarbituric acid reactive substances, reduced glutathione, and various enzymes associated with oxidative stress including peroxide metabolizing enzymes and xanthine oxidase. In thioacetamide treated group, many fold increase in the activity level of serum marker enzymes suggesting FHF was observed that could be brought down significantly in rats receiving boron. Modulation and a correlation in the activity level of oxidant generating enzyme and lipid peroxidation as well as hepatic glutathione level was also observed in rats receiving thioacetamide. In the group receiving boron followed by thioacetamide, these changes could be minimized moderately. The activity level of the peroxide metabolizing enzymes and the tripeptide glutathione, which decreased following thioacetamide treatment were moderately elevated in the group receiving boron followed by thioacetamide. The data clearly shows that borax partly normalizes the liver and offsets the deleterious effects observed in FHF by modulating the oxidative stress parameters.

Protective effects of zinc on lipid peroxidation, antioxidant enzymes and hepatic histoarchitecture in chlorpyrifos-induced toxicity

The present study investigated the hepatoprotective role of zinc in attenuating the toxicity induced by chlorpyrifos in rat liver. Male Sprague-Dawley (SD) rats received either oral chlorpyrifos (13.5mg/kg body weight), zinc alone (227mg/l in drinking water) or combined chlorpyrifos plus zinc treatment for a total duration of 8 weeks. The effects of these treatments were studied on various parameters in rat liver, including lipid peroxidation, antioxidant enzymes, levels of metallothionein (MT) and hepatic histoarchitecture. Chlorpyrifos treatment resulted in a significant increase in hepatic lipid peroxidation and activities of superoxide dismutase (SOD), glutathione peroxidase (G-Px) and glutathione reductase (GR). On the contrary, chlorpyrifos intoxication caused a significant inhibition in the levels of reduced glutathione (GSH), catalase (CAT) and glutathione-S-transferase (GST) activities. However, zinc treatment to chlorpyrifos-intoxicated animals normalized the otherwise raised levels of lipid peroxidation to within normal limits. Moreover, zinc treatment to these animals resulted in an elevation in the levels of GSH, catalase and GST, as well as a significant decrease in the levels of SOD. Levels of MT were also found to be depressed in chlorpyrifos-treated animals, but tended to increase following co-administration of zinc. Additionally, chlorpyrifos-treated animals demonstrated increased vacuolization, necrosis and ballooning of the hepatocytes and dilatation of sinusoids as well as increase in the number of binucleated cells. However, zinc administration to chlorpyrifos-treated animals resulted in overall improvement in the hepatic histoarchitecture, emphasizing the protective potential of zinc. Hence, the present study suggests the protective potential of zinc in alleviating the hepatic toxicity induced by chlorpyrifos.

Oxidative stress, toxic hepatitis, and antioxidants with particular emphasis on zinc

Hepatic metabolism of biological toxins, industrial poisons, and medicinal agents involves disturbed hepatic cell biochemistry with augmented generation of reactive oxygen species and free radicals and redox imbalance with secondary damage to proteins, nucleic acids, lipids, and carbohydrates. The xenobiotic hepatotoxicity ranging from a subclinical anicteric state to severe necroinflammatory hepatitis (acute, recurrent or chronic) and cirrhosis depends on the nature, dosage, and duration of exposure to the xenobiotic, the antioxidant defence, and concomitant exposure to other diseases or xenobiotics. Experimental and clinical studies suggest that xenobiotic hepatotoxicity with variable depletion of antioxidants can be avoided or ameliorated by administration of an unusually high dosage of zinc or by a combination of antioxidants above normal daily requirements. Therefore reassessment of optimal prophylactic and therapeutic nutritional requirements of antioxidants (particularly zinc) to defend humans against xenobiotic induced oxidative stress is advocated.