Showing papers in "Toxicology and Industrial Health in 2012"

Toxicity of zinc oxide nanoparticles through oral route.

Abstract: This experiment was aimed to determine the significance of dose by comparing acute oral toxicological potential of nano-sized zinc oxide (20 nm) with its micro-sized zinc oxide. Sprague Dawley rats, 8 to 9 weeks old, were administered with 5, 50, 300, 1000 and 2000 mg/kg body weight (b.w.) of nano- and micro-sized zinc oxide suspended in distilled water once through oral gavage. The effects of the micro- and nano-sized zinc oxide on biochemical and hematological parameters were analyzed on day 14 of administration. The organs were collected for histopathology. Interestingly, inverse dose-dependent increase was noted in aspartate aminotransferase, alanine aminotransferase serum levels of nano-size zinc oxide groups when compared with their micro-sized zinc oxide. Clotting time was effected in all the male groups of nano-size zinc oxide, except in 1000 mg/kg b.w. The incidences of microscopic lesions in liver, pancreas, heart and stomach were higher in lower doses of nano-size zinc oxide compared to higher dose. However, the incidences of above lesions were higher in rats treated with a high dose of micro-sized zinc oxide. We conclude that nano-size zinc oxide exhibited toxicity at lower doses, thus alarming future nanotoxicology research needs to be focused on importance of dose metrics rather following the conventional methods while conducting in vivo experiments.

Hypoglycemic effect of basil (Ocimum basilicum) aqueous extract is mediated through inhibition of α-glucosidase and α-amylase activities: an in vitro study.

Abstract: The present study investigated the in vitro hypoglycemic activity of basil (Ocimum basilicum) aqueous extract. Preliminary phytochemical screening of the extract revealed the presence of reducing s...

Anti-apoptotic effects of curcumin on cadmium-induced apoptosis in rat testes.

Abstract: Cadmium (Cd) is one of the environmental pollutants affecting various tissues and organs including testis. The aim of this study was to investigate the anti-apoptotic effects of curcumin (Cur) on Cd-induced apoptosis in rat testes. The rats were randomly allotted into one of three experimental groups: control, Cd treated and Cd treated with Cur; each group contained 10 animals. The control group received 2 ml/day of dimethyl sulfoxide (DMSO). To induce toxicity, Cd (1 mg/kg body weight) was dissolved in normal saline and subcutaneously injected into rats for 4 weeks. The rats in Cur-treated group was given a daily dose of 100 mg/kg of Cur for 4 weeks. To date, no examinations of the anti-apoptotic properties of Cur on Cd-induced apoptosis in rat testes have been reported. The mean seminiferous tubule diameter, mean testicular biopsy score values and serum testosterone levels were significantly decreased in Cd-treated groups were compared to the control group. Furthermore, the Cur-treated animals showed an improved histological appearance and serum testosterone levels in Cd-treated group. Our data indicate a significant reduction in the activity of in situ identification of apoptosis using terminal dUTP nick end-labeling in testis tissues of the Cd-treated group with Cur therapy. The present study showed that Cur treatment protected testes against toxic effects of Cd. We believe that further preclinical research into the utility of Cur may indicate its usefulness as a potential treatment on the spermatogenesis after testicular injury caused by Cd-treated rats.

Biochemical evidence on the potential role of organophosphates in hepatic glucose metabolism toward insulin resistance through inflammatory signaling and free radical pathways.

Abstract: Several studies show that organophosphate pesticides exert several effects on glucose homeostasis. The current study investigates the influence of subchronic exposure to malathion (MT) on hepatic gluconeogenesis in relation to acetyl cholinesterase (AChE) inhibition, oxidative stress and inflammatory response in the rat. MT was administered by gavage at doses of 25, 50 and 100 mg/kg for 32 days. Fasting hyperglycemia was seen in line with an increased activity of hepatic phosphoenolpyruvate carboxykinase, glucose 6-phosphatase and tumor necrosis factor α. In addition to the impaired glucose tolerance and inhibition of AChE in a dose-dependent manner, there were significant increases in hepatic lipid peroxidation, carbonyl groups and 8-deoxyguanosine as the biomarkers of reactive oxygen species-mediated damage to lipid, protein and DNA, respectively. Altered quality of the liver in glucose production especially gluconeogenesis could be a compensatory mechanism against MT toxicity or even result in tissue damage. MT-induced insulin resistance in the liver occurs through oxidative and inflammatory signaling pathways.

Electroencephalogram, cognitive state, psychological disorders, clinical symptom, and oxidative stress in horticulture farmers exposed to organophosphate pesticides.

Abstract: The aim of this paper was to study the toxicity of organophosphate (OP) pesticides in exposed farmers for electroencephalography, cognitive state, psychological disorders, clinical symptom, oxidati...

Free radical scavenging (DPPH) potential in nine Mentha species.

Abstract: Mentha species are used in every day life in various food items. These species produce valuable secondary metabolites that scavenge toxic free radicals. Toxic free radicals can cause different diseases in the human body. In the present study free radical scavenging potential (1,1-diphenyl-2-picrylhydrazyl scavenging activity) in nine Mentha species were investigated to evaluate and explore new potential sources for natural antioxidants. The activity was performed after different time intervals with incubation period of 30 minutes. The methanolic extracts revealed that significantly higher activity (82%) was observed in Mentha suaveolens, followed by Mentha longifolia (79%), Mentha officinalis (76%) and Mentha piperita, Mentha pulegium, Mentha royleana (75%), respectively. Significantly same activity was observed in Mentha arvensis and Mentha spicata. Lower activity was observed in Mentha citrata (64%). The present study revealed that these species can be used as natural antioxidants.

Baicalein inhibits oxidative stress-induced cellular damage via antioxidant effects.

Abstract: Baicalein (5,6,7-trihydroxyflavone) is a phenolic flavonoid compound derived mainly from the root of Scutellaria baicalensis Georgi, a medicinal plant traditionally used in oriental medicine. In our previous study, baicalein attenuated mitochondrial oxidative stress by scavenging reactive oxygen species (ROS) and by induction of nuclear factor erythroid 2-related factor 2 transcription factor-mediated manganese superoxide dismutase. In the present study, the protective effects of baicalein against oxidative stress-induced damage, especially cellular components including DNA, lipid, and protein, were studied. The results of this study showed that baicalein scavenged intracellular ROS. Baicalein inhibited the H₂O₂-induced DNA damage that was demonstrated by decreased phospho-H2A.X expression and DNA tail formation. In addition, it prevented the lipid peroxidation shown by the fluorescence intensity of diphenyl-1-pyrenylphosphine and the formation of thiobarbituric acid reactive substances. Moreover, baicalein inhibited protein oxidation demonstrated by protein carbonyl formation. Furthermore, baicalein protected cells via the inhibition of apoptosis induced by H₂O₂. The findings of this study suggest that baicalein provides protection for cellular components against oxidative damage via scavenging ROS and inhibiting apoptosis.

Antioxidant and antiapoptotic effects of capsaicin against carbon tetrachloride-induced hepatotoxicity in rats.

Abstract: The aim of the study was to evaluate the potential hepatoprotective utility of capsaicin against carbon tetrachloride (CCl₄)-induced liver injury and to explore the possible mechanisms whereby this agent mediated its beneficial effects. We randomized 40 rats into four groups for treatment with corn oil, CCl₄, capsaicin and both CCl₄ and capsaicin, respectively, for 8 weeks. At the end of the experiment, blood samples were collected and used for determination of aspartylaminotransferase (AST), alanine aminotransferase (ALT), and total bilirubin, while the liver tissues were subjected to hematoxylin and eosin examination; evaluation of malondialdehyde (MDA), reduced glutathione (GSH) and active caspase-3 contents; and evaluation of superoxide dismutase (SOD), catalase (CAT) and glutathione-S-transferase (GST) activities. Animals treated with CCl₄ exhibited significant elevation in AST, ALT, total bilirubin and caspase-3 and exhibited significant decrease in activities of SOD, CAT, GST and GSH contents. The combination (both capsaicin and CCl₄) group has preserved the liver histology, liver enzymes and bilirubin close to normal, exhibited significant induction in the activities of CAT, SOD and GST, increased the liver content of GSH and active caspase-3 and conversely showed significant decrease in liver MDA content compared to CCl₄ challenged rats. Capsaicin confers an appealing hepatoprotective effect which might be explained partially via diminishing the generation of MDA, induction of antioxidant systems and inhibition of active caspase-3.

A weight of evidence approach for the assessment of the ototoxic potential of industrial chemicals

Abstract: There is accumulating epidemiological evidence that exposure to some solvents, metals, asphyxiants and other substances in humans is associated with an increased risk of acquiring hearing loss. Furthermore, simultaneous and successive exposure to certain chemicals along with noise can increase the susceptibility to noise-induced hearing loss. There are no regulations that require hearing monitoring of workers who are employed at locations in which occupational exposure to potentially ototoxic chemicals occurs in the absence of noise exposure. This project was undertaken to develop a toxicological database allowing the identification of possible ototoxic substances present in the work environment alone or in combination with noise exposure. Critical toxicological data were compiled for chemical substances included in the Quebec occupational health regulation. The data were evaluated only for noise exposure levels that can be encountered in the workplace and for realistic exposure concentrations up to the short-term exposure limit or ceiling value (CV) or 5 times the 8-h time-weighted average occupational exposure limit (TWA OEL) for human data and up to 100 times the 8-h TWA OEL or CV for animal studies. In total, 224 studies (in 150 articles of which 44 evaluated the combined exposure to noise and a chemical) covering 29 substances were evaluated using a weight of evidence approach. For the majority of cases where potential ototoxicity was previously proposed, there is a paucity of toxicological data in the primary literature. Human and animal studies indicate that lead, styrene, toluene and trichloroethylene are ototoxic and ethyl benzene, n-hexane and p-xylene are possibly ototoxic at concentrations that are relevant to the occupational setting. Carbon monoxide appears to exacerbate noise-induced hearing dysfunction. Toluene interacts with noise to induce more severe hearing losses than the noise alone.

Diazinon-induced brain toxicity and protection by vitamins E plus C.

Abstract: Diazinon (DI) is a widely used pesticide in agriculture, resulting in environmental deleterious effects on neural systems. The current study was performed to investigate the effects of treatment with vitamins E plus C on brain toxicity, which is possibly induced by DI. Twenty-one male rats were divided into three groups (n = 7/group) as follows: (1) control group (C); (2) DI-treated group (DI); (3) DI + vitamins E plus C-treated group (DI + Vit). In order to examine lipid peroxidation and antioxidant status in rats, the level of malondialdehyde (MDA), activities of two free radical scavanging enzymes superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) have been studied in brain of rat. The results showed that treatment with DI induced significant (p < 0.05) increases in the level of serum MDA in rat brain. The vitamins E plus C combination reduced lipid peroxidation in rat brain. The activity of SOD level was significantly higher in DI + Vit group, compared to the control group. GSH-Px, SOD and CAT values were not significantly different in the DI group than in control. Oxidative stress contributes to DI-induced brain toxicity. Our results suggested that vitamins E plus C combination may have a protective effect on DI-induced brain toxicity.

Bioaccumulation and elimination of nickel in the organs of black fish (Capoeta fusca)

Abstract: Since toxicity is based on the effect that a toxicant produces at a target site within an organism, establishing the relationship between the concentration of substance at the target site and the s...

Ameliorative effect of docosahexaenoic acid on 2,3,7,8-tetrachlorodibenzo-p-dioxin-induced histological changes, oxidative stress, and DNA damage in rat liver.

Abstract: 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is an environmental contaminant that leads to the development of hepatotoxicity. Docosahexaenoic acid (DHA) has been proposed to counteract oxidative stress and improve antioxidant status, and several studies suggest that supplementations with antioxidants can influence hepatotoxicity. The aim of the current study was to explore the role of DHA in modulating the toxicity of TCDD in the liver of Sprague-Dawley rats. Animals were assigned to four groups (n = 5): control (only dimethyl sulfoxide (DMSO)), 8 μg/kg body weight (b.w.) TCDD in DMSO solution; 250 mg/kg b.w. DHA and TCDD plus DHA; respectively. Rats were intraperitoneally administered their respective doses daily for 21 days. On day 21, the animals were killed, and then biochemical tests, pathological examination, and micronucleus (MN) assay were performed in the liver. Our results showed that the activities of antioxidant enzymes were significantly decreased and serious pathological findings were established in rats that received TCDD. Beside the rate of MNs in hepatocytes was increased after the treatment with dioxin. In rats treated with DHA alone, MNs were not changed and the activities of antioxidant enzymes were significantly increased. The presence of DHA with TCDD alleviated its pathological effects in hepatic tissue. DHA also prevented the suppression of antioxidant enzymes in the livers of animals exposed to TCDD and displayed a strong protective effect against MNs. It can be concluded that DHA has beneficial influences and could be able to antagonize TCDD toxicity in liver.

Antiapoptotic and proliferative activity of curcumin on ovarian follicles in mice exposed to whole body ionizing radiation.

Abstract: The aim of this study was to evaluate the antiapoptotic and proliferative activity of curcumin (Cur) on the ovarian follicles in mice exposed to whole body ionizing radiation (Rd). The mice were exposed to 8.3 gray whole body Rd, and Cur groups were given as a daily dose of 100 mg/kg of Cur for 10 days (10 days before Rd). The ovaries were collected 3 and 12 h after irradiation. To date, no such studies have been performed on antiapoptotic and proliferative activity of Cur on the ovarian follicles in mice exposed to whole body Rd. Analysis of mice ovary after exposure to Rd by terminal-deoxynucleotidyl-transferase-mediated dUTP nick end labeling showed that there were apoptotic cells both in the follicular wall and the antrum, and that the number of follicles showing early atresic features was high 3 h after Rd. On the other hand, analysis of mice ovary 12 h after exposure to Rd showed that the number of follicles containing apoptotic cells with advanced atresic features was significantly higher when comp...

Anti-inflammatory and antioxidant effects of infliximab in a rat model of intestinal ischemia/reperfusion injury

Abstract: The aim of this study was to investigate the possible protective effects of infliximab on oxidative stress, cell proliferation and apoptosis in the rat intestinal mucosa after ischemia/reperfusion ...

Acute toxicity bioassay of mercury and silver on Capoeta fusca (black fish).

Abstract: Since toxicity is based on the effect that a toxicant produces at a target site within an organism, establishing the relationship between the concentration of substance at the target site and the subsequent toxic effect can provide a tool for predicting toxicity. The behavior of a single toxicant could not be fully understood without the knowledge of the fact the physical and biochemical properties of substances that can change. To understand this, the acute toxicity of mercury (as HgSO4) and silver (as AgSO4) to Capoeta fusca (6 treatments in triplicate) was determined. During September 2009, C. fusca belonging to the family Cyprinidae, weighing 2.95 (±0.55) g, were obtained from qanats in Birjand, East of Iran. The fish were maintained in an aquarium system at a holding temperature of 21 (±0.2) and were allowed to adjust to lab conditions for 1 week before experimentation. The lethal concentration 50 (LC50) values for HgSO4 at 24, 48, 72, and 96 h of exposure were 0.32, 0.28, 0.26, and 0.24 mg L–1, resp...

Review of melamine scandal: still a long way ahead.

Abstract: In September 2008, in China, tens of thousands of children were hospitalized, several even died, as a result of infant-formula milk adulterated with a synthetic chemical compound, melamine, and in the next few months, this crisis became the focus of attention worldwide. Although there are a number of articles about melamine toxicity on different species of animals, the long-term effect of melamine on humans is still unknown. Besides, several recent in vitro studies indicated that melamine can damage cells of other parts of the body, including the central nervous system, breaking the previous view that melamine toxicity is limited to the urinary system. Hence, we strongly recommend a long-term follow-up for the overall health status of the victims, not confined to kidneys, to minimize the potential toxic effects in their later life; and research to study the specific mechanism of melamine should be encouraged.

Municipal landfill leachate induces hepatotoxicity and oxidative stress in rats.

Abstract: Human beings are more often exposed to complex mixtures of hazardous chemicals than single toxicant. The present study investigated the effects of Olushosun municipal landfill leachate (OMLL) from Ojota in Lagos State of Nigeria on hepatic function and some biomarkers of oxidative stress in adult rats. Physicochemical characteristic analysis of OMLL showed that while total alkalinity, total acidity, total hardness, biochemical oxygen demand and chemical oxygen demand were 3-fold, 2-fold, 4-fold and 1-fold, respectively, concentrations of heavy metals analysis showed that copper, lead, cadmium, arsenic, cobalt, chromium and mercury were 9-fold, 4-fold, 21-fold, 1320-fold, 7-fold, 5-fold and 4-fold, respectively, higher than acceptable limits by regulatory authorities. The OMLL was administered at 0, 10, 20, 30 and 40% concentrations to adult male rats for 14 days. Following exposure, serum was collected for serum biochemistry assays and liver was collected to determine the antioxidant status. Exposure of animals to 10, 20, 30 and 40% OMLL resulted in 3%, 31%, 52% and 83% increase in aspartate aminotransferase activity, whereas it elevated alanine aminotransferase activity by 10%, 25%, 30% and 49%, respectively, when compared with the control. While OMLL administration significantly increased catalase activity, a sequential decrease in reduced glutathione level and in superoxide dismutase and glutathione-S-transferase activities with concomitant increase in malondialdehyde level were observed, when compared with the control. Collectively, the hepatotoxicity of OMLL could be due to the induction of oxidative stress and may suggest possible health hazards in subjects with occupational or environmental exposure.

Protective role of caffeic acid on lambda cyhalothrin-induced changes in sperm characteristics and testicular oxidative damage in rats

Abstract: The synthetic pyrethroids are expected to cause deleterious effects on most of the organs and especially on the male reproductive system. The current study was performed to assess the adverse effect of lambda cyhalothrin (LC) on reproductive organs and fertility in male rats and to evaluate the protective role of caffeic acid phenethyl ester (CAPE) in alleviating the detrimental effect of LC on male fertility. A total of 48 male rats were divided into 4 groups (12 rats each): control group received distilled water ad libitum and 1 ml of vehicle solution given intraperitoneally (i.p.); CAPE-treated group received a single i.p. dose of CAPE (10 μmol kg⁻¹ day⁻¹); LC-treated group received 668 ppm of LC through drinking water; and CAPE + LC-treated group received an i.p. injection of CAPE (10 μmol kg⁻¹ day⁻¹) 12 h before the LC administration. The experiment was conducted for 10 consecutive weeks. LC caused a significant increase in testicular malondialdehyde, catalase, superoxide dismutase, glutathione-S-transferase activities, and sperm abnormalities and a significant reduction in testicular glutathione concentration, sperm count, sperm motility, and a live sperm percentage. Conversely, treatment with CAPE improved the reduction in the sperm characteristics, LC-induced oxidative damage of testes and the testicular histopathological alterations. Results indicate that LC exerts significant harmful effects on the male reproductive system and that CAPE reduced the deleterious effects of LC on male fertility.

Protective effect of Emblica officinalis (amla) on isoproterenol-induced cardiotoxicity in rats

Abstract: Emblica officinalis, commonly known as amla, is an important medicinal plant reputed for its dietary and therapeutic uses. The aim of the present study was to investigate the protective role of E. officinalis against isoproterenol (ISP)-induced cardiotoxicity in rats and elucidate the possible mechanism involved. Rats were administered E. officinalis (100, 250 and 500 mg/kg, p.o.) or vehicle (normal saline) for 30 days, with concurrent subcutaneous injections of ISP (85 mg/kg, at 24 h interval) on 29th and 30th day. ISP-induced cardiac dysfunction as evidenced by decreased mean arterial pressure, heart rate, contractility (+LVdP/dt) and relaxation (-LVdP/dt) along with increased left ventricular end diastolic pressure. ISP significantly (p < 0.05) decreased antioxidant enzymes, superoxide dismutase, catalase and glutathione peroxidase and myocyte-injury-specific marker enzymes, creatine phosphokinase-MB and lactate dehydrogenase in heart. A significant (p < 0.05) depletion of reduced glutathione and increase in thiobarbituric acid reactive substances along with histopathological alteration has further indicated the oxidative damage of myocardium. However, pretreatment with E. officinalis exhibited restoration of hemodynamic and left ventricular function along with significant preservation of antioxidants, myocytes-injury-specific marker enzymes and significant inhibition of lipid peroxidation. Furthermore, histopathological salvage of myocardium reconfirmed the protective effects of E. officinalis. Results of the present study demonstrate cardioprotective potential of E. officinalis attributed to its potent antioxidant and free radical scavenging activity as evidenced by favorable improvement in hemodynamic, contractile function and tissue antioxidant status.

Prevention of rat breast cancer by genistin and selenium

Abstract: Breast cancer is the second leading cause of cancer death among women and the third most common cancer. In this study, we investigated the chemoprevention efficacy of each of soy genistin, selenium or a combination of them against breast cancer. Seventy-five female rats were divided into five groups : control group (I); 7,12-dimethylbenz(a)anthracene (DMBA) group (II); DMBA treated with genistin group (III); DMBA treated with selenium group (IV); and DMBA treated with genistin combined with selenium group (V). The treatments were daily administered for 3 months. There were a significant decrease in body weight and serum total antioxidant, while a significant elevation in serum total sialic acid, carcinoembryonic antigen, prolactin, estradiol, nitric oxide, and malondialdhyde of DMBA injected rats compared with control group. Administration of genistin and selenium was associated with decreasing levels of tumorigenicity, endocrine derangement, and oxidative stress. Formation of breast carcinoma in DMBA-induced rats and abnormal changes were ameliorated in the rats treated with genistin/selenium or genistin alone. Supplementation of genistin alone or with selenium provided antioxidant defense with high-potential chemopreventive activity against DMBA-induced mammary tumors more than selenium alone.

Methamphetamine exposure and chronic illness in police officers: significant improvement with sauna-based detoxification therapy

Abstract: Background: The medical literature reports health hazards for law enforcement personnel from repeated exposuretomethamphetamineandrelatedchemicalcompounds.Mosteffectsappeartransitory,butsomeUtah police officers with employment-related methamphetamine exposures developed chronic symptoms, some leadingtodisability.Thisreportisofanuncontrolledretrospectivemedicalchartevaluationofsymptomaticofficers treated with a sauna detoxification protocol designed to reduce the chronic symptoms and improve the quality of life. Methods: Sixty-nine officers consecutively entering the Utah Meth Cops Project were assessed beforeandafteratreatmentprograminvolvinggradualexercise,comprehensivenutritionalsupportandphysical sauna therapy. Evaluations included pre- and post-treatment scores of the Research and Development Corporation (RAND) 36-item Short Form Health Survey (SF-36) in comparison with RAND population norms, preand post-treatment symptom score intensities, neurotoxicity scores, Mini-Mental Status Examination, presentingsymptomfrequenciesandastructuredevaluationoftreatmentprogramsafety.Results:Statisticallysignificant healthimprovementswereseenintheSF-36evaluations,symptomscoresandneurotoxicityscores.Thedetoxificationprotocolwaswelltolerated,witha92.8%completionrate.Conclusions:Thisinvestigationstronglysuggests that utilizing sauna and nutritional therapy may alleviate chronic symptoms appearing after chemical exposuresassociatedwithmethamphetamine-relatedlawenforcementactivities.Thisreportalsohasrelevance to addressing the apparent ill effects of other complex chemical exposures. In view of the positive clinical outcomes in this group, broader investigation of this sauna-based treatment regimen appears warranted.

Effect of fenugreek seed extract on adriamycin-induced hepatotoxicity and oxidative stress in albino rats:

Abstract: The purpose of this work was to evaluate the effect of aqueous extract of fenugreek seeds against hepatotoxicity induced in albino rats by the anticancer drug adriamycin (ADR). Animals were given single dose of ADR (10 mg/kg body weight) and were killed after 2 and 4 weeks. Liver of ADR-treated animals showed histopathological and biochemical alterations. The histopathological changes include hepatic tissue impairment, cytoplasmic vacuolization of the hepatocytes, congestion of blood vessels, leucocytic infiltrations and fatty infiltration. Moreover, the expression of proliferating cell nuclear antigen was increased in ADR-treated rats. The liver enzymes, aspartate aminotransferase (ALT) and alanine aminotransferase (AST) were increased in the sera of treated rats. Moreover, ADR significantly increased the concentration of malondialdehyde (MDA) and decreased the activities of superoxide dismutase (SOD) and catalase (CAT) in hepatic tissue. Treating animals with ADR and aqueous extract of fenugreek (0.4 g/kg body weight) seeds led to an improvement in histological and biochemical alterations induced by ADR. The biochemical results showed that AST and ALT appeared normal together with reduction in the level of MDA (lipid peroxidation marker) and increase in SOD and CAT activities. It was concluded from this study that the aqueous extract fenugreek seeds has a beneficial impact on ADR-induced hepatotoxicity due to its antioxidant effect in albino rats.

Ameliorating effects of quercetin and chrysin on 2,3,7,8-tetrachlorodibenzo- p-dioxin-induced nephrotoxicity in rats.

Abstract: The aim of this study is to investigate the beneficial effects of the quercetin (Q) and chrysin (CH) against nephrotoxicity induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a persistent envir...

Protective effect of vanillin against carbon tetrachloride (CCl₄)-induced oxidative brain injury in rats.

Abstract: This study investigated the protective effects of vanillin against acute brain damage induced by carbon tetrachloride (CCl₄) in rats. The study was performed on 32 male rats divided into four groups: a control group, vanillin group ([Va] 150 mg/kg/day, intraperitoneally [i.p.]) and CCl₄ toxication groups received a single injection of CCl₄ (1 ml/kg, i.p.; CCl₄ and Va + CCl₄ groups). The degree of protection in brain tissue was evaluated by the levels of malondialdehyde (MDA), glutathione (GSH), superoxide dismutase, glutathione transferase, glutathione peroxidase and nitric oxide (NO). Vanillin showed a significant brain-protective effect by decreasing the level of lipid peroxidation and NO₂ and elevated the activities of antioxidative enzymes and level of GSH. Consequently vanillin blocked oxidative brain damage induced by CCl₄ in rats.

Ameliorative effect of vitamin C on hexavalent chromium-induced delay in sexual maturation and oxidative stress in developing Wistar rat ovary and uterus.

Abstract: Hexavalent chromium (CrVI) is a highly toxic metal and major environmental pollutant and is extensively used in more than 50 industries. The major route of CrVI exposure for the general population is oral intake. Chromium is considered an important nutrient responsible for carbohydrate metabolism. However, excess CrVI exposure is associated with various pathological conditions including reproductive dysfunction. CrVI can traverse the placental barrier and cause wide range of abnormalities in fetal development. Cr is transported to offspring through mother's milk in lactating women exposed to CrVI. Therefore, the present study was carried out to determine the toxic effects of lactational CrVI exposure on ovary and uterus and the beneficial role of vitamin C in preventing/ameliorating the toxic effects of CrVI in developing female Wistar rats. Generation of oxidative stress is considered one of the plausible mechanisms behind Cr-induced cellular deteriorations. The present study evidenced a decrease in the specific activities of antioxidants, serum testosterone and progesterone and an increase in the levels of H₂O₂, lipid peroxidation (LPO) and follicle stimulating hormone in rats exposed to CrVI when compared to control. CrVI exposure also delayed the sexual maturation and extended the estrous cycle. Simultaneous administration of vitamin C significantly prevented the increase in LPO and enhanced the antioxidant status. These results suggest the protective effect of vitamin C against the CrVI exposure-induced toxicity and attest the significance of antioxidants in diet.

The effect of folic acid as an antioxidant on the hypothalamic monoamines in experimentally induced hypothyroid rat

Abstract: Thyroid hormones are recognized as key metabolic hormones that play a critical role in the central nervous system development throughout life. In the present study, we studied the biochemical changes of hypothalamus of hypothyroid rats at post-pubertal stage, and the possible ameliorating effect of folic acid. A total of 50 male albino rats were equally divided into five groups; the first and second groups were the control and folic acid groups, respectively, while the third group was the hypothyroid group in which rats received daily 6-n-propyl-2-thiouracil (PTU) in drinking water for 6 weeks to induce hypothyroidism. The fourth and fifth groups were hypothyroid rats treated with folic acid for 4 weeks during and after receiving PTU, respectively, and were dissected after 6 and 10 weeks, respectively. There was a significant increase in plasma total homocysteine, malondialdehyde (MDA), oxidized glutathione\reduced glutathione and total nitric oxide and hypothalamic MDA, serotonin and norepinephrine in th...

Hepatic megalocytosis due to vanadium inhalation: participation of oxidative stress.

Abstract: The aim of this study was to evaluate the morphological changes, liver function test (LFT), and oxidative stress damage caused by thiobarbituric acid reactive substances (TBARS), in mice exposed to vanadium via inhalation. Male CD-1 mice were exposed to vanadium pentoxide (V2O5) via inhalation (0.02 M), 1 hour twice a week for 6 weeks. At the end of the protocol, controls and exposed mice were killed to evaluate the changes. Histological analysis and LFT were performed to detect the damage. TBARS detection was assessed for oxidative stress. Inflammatory infiltration, binucleation, and meganucleus were detected in the liver of V2O5-exposed mice (p < 0.05). Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were also significantly increased (p < 0.05). Lipid peroxidation was significantly higher in V2O5-exposed animals compared to controls (p < 0.05). V2O5 exposure induced inflammation and cell damage detected by the increase in ALT and AST levels, as well as histological changes tha...

DNA and oxidative damage induced in somatic organs and tissues of mouse by municipal sludge leachate.

Abstract: Pollution by waste landfill leachate has prompted a number of studies on the toxic and potential health effects. This study assessed the genotoxicity of a municipal sludge leachate (MSL) in the som...

Cadmium and lead content in several brands of rice grains (Oryza sativa) in central Iran.

Abstract: The aim of this study was to investigate the cadmium (Cd) and lead (Pb) content of several commercially available brands of rice grains (Oryza sativa) in central Iran. A total of 67 samples of the most widely consumed brands of rice grains were purchased from local bazaar markets in Shahrekord, Iran. The first step, grains of raw rice were digested by acid digestion method and then were analyzed by atomic absorption spectrometer. The results showed that Cd concentration in rice grains ranged from 0.0378 to 0.1225 ppm dry weight and its average concentration was 0.062 ± 0.019 ppm and Pb content ranged from 0.0405 to 0.1281 ppm dry weight and its average concentration was 0.068 ± 0.0185 ppm. Cd and Pb concentrations in the sampled rice grains were lower in comparison with their upper limits (0.2 and 0.2 ppm for Cd and Pb, respectively) approved by food sanitary standard. Therefore, it can be concluded that there is no health problems due to the consumption of brands of rice grains, for these two elements. The results indicated that weekly intake of Cd and Pb from rice grains was below the provisional tolerable weekly intakes recommended by WHO/FAO.

Effect of combined occupational exposure to noise and organic solvents on hearing

Abstract: Noise exposure has been commonly regarded as the main hazard of occupational hearing loss. Recent studies indicate that several chemicals, including organic solvents have ototoxic effects. This stu...