Homologous recombination initiated by benzene metabolites: a potential role of oxidative stress.

Benzene is a ubiquitous pollutant and known human leukemogen. Benzene can be enzymatically bioactivated to reactive intermediates that can lead to increased formation of reactive oxygen species (ROS). ROS formation can directly induce DNA double-strand breaks, and also oxidize nucleotides that are subsequently converted to double-strand breaks during DNA replication that can be repaired through homologous recombination, which is not error-free. Therefore increased DNA double-strand-break levels may induce hyper-recombination, which can lead to deleterious genetic changes. To test the hypothesis that benzene and its metabolites can initiate hyper-recombination and to investigate the potential role of ROS, a Chinese hamster ovary (CHO) cell line containing a neo direct repeat recombination substrate (CHO 3-6), was used to determine whether benzene or its metabolites phenol, hydroquinone, catechol, or benzoquinone initiated increased homologous recombination and whether this increase could be diminished by the coincubation of cells with the antioxidative enzyme catalase. Results demonstrated that cells exposed to benzene (1, 10, 30, or 100 micro M) for 24 h did not exhibit increased homologous recombination. Increased recombination occurred with exposure to phenol (1.8-, 2.6-, or 2.9-fold), catechol (1.9-, 2-, 5-, or 3.2-fold), or benzoquinone (2.7-, 5.5-, or 6.9-fold) at 1, 10, and 30- micro M concentrations, respectively, and with exposure to hydroquinone at 10 and 30 micro M concentrations (1.5-1.9-fold; p < 0.05). Studies investigating the effects of catalase demonstrated that increased homologous recombination due to exposure to phenol, hydroquinone, catechol, or benzoquinone (10 micro M) could be completely abolished by the addition of catalase. These data support the hypothesis that increased homologous recombination mediates benzene-initiated toxicity and supports a role for oxidative stress in this mechanism.     

Lipid mediator interplay: resolvin D1 attenuates inflammation evoked by glutathione-conjugated lipid peroxidation products

Non-enzymatic oxidation of cellular lipids, one of the characteristic features of inflammation, leads to formation of highly reactive and toxic α,β-unsaturated aldehydes, such as 4-hydroxy-trans-2-nonenal (HNE). Conjugation of HNE with reduced glutathione (GS-HNE) is widely believed to represent a form of detoxification. The study by Spite et al. in the current issue of the British Journal of Pharmacology shows that glutathiolation of HNE confers potent pro-inflammatory properties on this α,β-unsaturated aldehyde. They find that GS-HNE directly activates human neutrophil granulocytes in vitro and evokes peritonitis in mice. Pre-treatment with resolvin D1, which is derived from ω-3 fatty acids, markedly attenuated the peritoneal leukocyte accumulation and production of prostaglandins and leukotrienes induced by GS-HNE. Their findings have profound implications for the analysis of inflammation in describing the generation of a novel class of pro-inflammatory mediators, through glutathione-dependent metabolism of lipid-peroxidation products, and emphasize the therapeutic potential of resolvin D1 in inflammatory diseases.This article is part of a themed issue on Mediators and Receptors in the Resolution of Inflammation. To view this issue visit http://www3.interscience.wiley.com/journal/121548564/issueyear?year=2009     

Oral isotretinoin therapy of acne patients decreases serum paraoxonase-1 activity through increasing oxidative stress

Objectives: There are only a few earlier studies suggesting relationship between isotretinoin treatment and oxidative stress however, their results are conflicting. Therefore we aimed to concretize the influence of isotretinoin treatment on oxidant/antioxidant status together with paraoxonase-1 (PON1) activity for the first time. Methods: The study was performed on serum samples obtained from 35 acne vulgaris patients before and after three months of isotretinoin treatment. PON1 activity, total oxidant status (TOS), total antioxidant capacity (TAC), oxidative stress index (OSI) and some routine biochemical parameters were monitored. Results: Dramatically decreased PON1 activity (p?p?0.001 and p?0.001; respectively) as well as slightly diminished TAC level were noted in posttreatment stage. Moreover significant increases were observed in lactate dehydrogenase and gamma glutamyl transpeptidase activities and levels of total cholesterol, low density lipoprotein cholesterol, very low density lipoprotein cholesterol, triglycerides, low density lipoprotein cholesterol/high density lipoprotein cholesterol ratio respectively (p?0.05, p?0.001, p?0.001, p?0.001, p?0.001, p?0.001 and p?0.001) while marked decrease was seen in high density lipoprotein cholesterol (p?0.01). Conclusion: This study revealed that decreased PON1 activity and increased oxidative stress may have a crucial role in the pathogenesis of isotretinoin’s side effects. Further studies on a large number of patients are needed to verify these results.     

Pyocyanin induces systemic oxidative stress,inflammation and behavioral changes in vivo

Pyocyanin (PCN) is a virulence factor secreted by Pseudomonas aeruginosa (P. aeruginosa) that has been shown to have numerous toxic effects in both in vitro and in vivo studies. Such toxicities include pro-inflammatory and pro-oxidant mediated responses. It is hypothesized that PCN can cross biological membranes and reach the systemic circulation, but no previous studies have investigated this. The aim of this study was, therefore, to quantify PCN in plasma and assess if systemic responses were occurring after localized intranasal administration in C57BL/6?J mice. This was achieved through the plasma quantification of PCN and assessment of changes to behavior using two commonly used tests, the forced swimming test and the open field test. Furthermore, evidence of systemic oxidative stress and inflammation was measured using malondialdehyde (MDA) and TNF-α post PCN exposure. PCN was found to cross into systemic circulation but in a variable manner. Furthermore, significant increases in plasma TNF-α and MDA (both p?相似文献   

Quercetin protects human peripheral blood mononuclear cells from OTA‐induced oxidative stress,genotoxicity, and inflammation

Ochratoxin A (OTA) is one of the most abundant food‐contaminating mycotoxins world wide, and is detrimental to human and animal health. This study evaluated the protective effect of quercetin against OTA‐induced cytotoxicity, genotoxicity, and inflammatory response in lymphocytes. Cytotoxicity determined by MTT assay revealed IC₂₀ value of OTA to be 20 µM, which was restored to near control values by pretreatment with quercetin. Oxidative stress parameters such as antioxidant enzymes, LPO and PCC levels indicated that quercetin exerted a protective effect on OTA‐induced oxidative stress. Quercetin exerted an antigenotoxic effect on OTA‐induced genotoxicity, by significantly reducing the number of structural aberrations in chromosomes and comet parameters like, % olive tail moment from 2.76 ± 0.02 to 0.56 ± 0.02 and % tail DNA from 56.23 ± 2.56 to 12.36 ± 0.56 as determined by comet assay. OTA‐induced NO, TNF‐α, IL‐6, and IL‐8 were significantly reduced in the quercetin pretreated samples indicating its anti‐inflammatory role. Our results demonstrate for the first time that quercetin exerts a cytoprotective effect against OTA‐induced oxidative stress, genotoxicity, and inflammation in lymphocytes. © 2014 Wiley Periodicals, Inc. Environ Toxicol 31: 855–865, 2016.     

Berberine attenuates inflammation and oxidative stress and modulates lymphocyte E-NTPDase in acute hyperlipidemia

Hyperlipidemia is a common clinically encountered health condition worldwide that promotes the development and progression of cardiovascular diseases, including atherosclerosis. Berberine (BBR) is a natural product with acknowledged anti-inflammatory, antioxidant, and metabolic effects. This study evaluated the effect of BBR on lipid alterations, oxidative stress, and inflammatory response in rats with acute hyperlipidemia induced by poloxamer-407 (P-407). Rats were pretreated with BBR (25 and 50 mg/kg) for 14 days and acute hyperlipidemia was induced by a single dose of P-407 (500 mg/kg). BBR ameliorated hypercholesterolemia, hypertriglyceridemia, and plasma lipoproteins in P-407-adminsitered rats. Plasma lipoprotein lipase (LPL) activity was decreased, and hepatic 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) reductase activity was enhanced in hyperlipidemic rats. The expression of low-density lipoprotein receptor (LDL-R) and ATP-binding cassette transporter 1 (ABCA1) was downregulated in hyperlipidemic rats. BBR enhanced LPL activity, upregulated LDL-R, and ABCA1, and suppressed HMG-CoA reductase in P-407-administered rats. Pretreatment with BBR ameliorated lipid peroxidation, nitric oxide (NO), pro-inflammatory mediators (interleukin [IL]-6, IL-1β, tumor necrosis factor [TNF]-α, interferon-γ, IL-4 and IL-18) and enhanced antioxidants. In addition, BBR suppressed lymphocyte ecto-nucleoside triphosphate diphosphohydrolase (E-NTPDase) and ecto-adenosine deaminase (E-ADA) as well as NO and TNF-α release by macrophages isolated from normal and hyperlipidemic rats. In silico investigations revealed the binding affinity of BBR toward LPL, HMG-CoA reductase, LDL-R, PSK9, ABCA1, and E-NTPDase. In conclusion, BBR effectively prevented acute hyperlipidemia and its associated inflammatory responses by modulating LPL, cholesterolgenesis, cytokine release, and lymphocyte E-NTPDase and E-ADA. Therefore, BBR is an effective and safe natural compound that might be employed as an adjuvant against hyperlipidemia and its associated inflammation.     

坛紫菜硫酸多糖对60Co辐射引起的小鼠体内氧化应激的作用研究

应用生物化学的方法探讨在^60Co辐射条件下，坛紫菜硫酸多糖对小鼠体内氧化应激的抑制作用。结果表明，^60Co辐射能显著降低昆明种小鼠体内不同脏器组织匀浆SOD、GSH—Px的活性，引起脂质过氧化。坛紫菜硫酸多糖可提高辐射损伤后小鼠组织匀浆SOD、GSH—Px的活性，增强总抗氧化能力，减少脂质过氧化。     

Lophirones B and C prevent aflatoxin B1-induced oxidative stress and DNA fragmentation in rat hepatocytes

Context Despite the reported anticarcinogenic activity of lophirones B and C, no scientific information exists for its activity in rat hepatocytes.

Objective Effect of lophirones B and C on aflatoxin B₁ (AFB₁)-induced oxidative stress, and DNA fragmentation in rat hepatocytes was investigated.

Materials and methods Wistar rat hepatocytes were incubated with lophirones B and C (1?mg/mL) or sylimarin (1?mg/mL) in the presence or absence of AFB₁. For an in vivo study, rats were orally administered with lophirones B and C, and/or AFB₁ (20?μg/d) for 9 weeks.

Results Lophirones B and C lowered AFB₁-mediated increase in nitric oxide, superoxide anion radicals, caspase-3 and fragmented DNA. Lophirones B and C attenuated AFB₁-mediated decrease in superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, and reduced glutathione. Also, lophirones B and C attenuated AFB₁-mediated increase in conjugated dienes, lipid hydroperoxides and malondialdehyde in rat hepatocytes. Furthermore, AFB₁-mediated alterations in alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, albumin, total bilirubin and globulin in rat serum were significantly annulled in lophirones B and C-treated rats.

Conclusion This study revealed that lophirones B and C prevented AFB₁-induced oxidative damage in rat hepatocytes.     

Mechanisms for the induction of oxidative stress in Syrian hamster embryo cells by acrylonitrile.

Chronic administration of acrylonitrile to rats resulted in an increase in the incidence of glial neoplasms of the brain. Recent studies have shown that acrylonitrile induces oxidative stress in rat brain and cultured rat glial cells. Acrylonitrile also induces morphological transformation concomitant with an increase in the formation of oxidized DNA in Syrian Hamster Embryo (SHE) cells in a dose-dependent manner. The mechanism for the induction of oxidative stress in SHE cells remains unresolved. The present study examined the effects of acrylonitrile on enzymatic and nonenzymatic antioxidants in SHE cells. SHE cells were treated with subcytolethal doses of acrylonitrile (0, 25, 50, and 75 microg/ml) for 4, 24, and 48 h. Acrylonitrile (50 microg/ml and 75 microg/ml) increased the amount of reactive oxygen species in SHE cells at all time points. Glutathione (GSH) was depleted and catalase and superoxide dismutase activities were significantly decreased in SHE cells after 4 h of treatment. The inhibition of these antioxidants was temporal, returning to control values or higher after 24 and 48 h. Xanthine oxidase activity was increased following 24 and 48 h treatment with acrylonitrile. 1-aminobenzotriazole, a suicidal P450 enzyme inhibitor, attenuated the effects of acrylonitrile on catalase and xanthine oxidase in SHE cells, suggesting that P450 metabolism is required for acrylonitrile to produce its effects on these enzymes. Additional studies showed that in the absence of metabolic sources acrylonitrile had no effect on either catalase or superoxide dismutase activity. These results suggest that the induction of oxidative stress by acrylonitrile involves a temporal decrease in antioxidants and increase in xanthine oxidase activity that is mediated by oxidative metabolism of acrylonitrile.     

The physiological stress response and oxidative stress biomarkers in rainbow trout and brook trout from selenium‐impacted streams in a coal mining region

Selenium (Se) is an essential element that can be toxic at concentrations slightly greater than those required for homeostasis. The main chronic toxic effects of Se in fish are teratogenic deformities, but Se can also activate the physiological stress response and redox cycle with reduced glutathione causing oxidative damage. Rainbow trout, Oncorhynchus mykiss, appear to be more sensitive to Se than brook trout, Salvelinus fontinalis. The objective of this study was to compare the physiological stress response (plasma cortisol, glucose, triiodothyronine, thyroxine, gill Na⁺/K⁺ ATPase, cortisol secretory capacity, K and liver somatic index) and oxidative stress biomarkers (liver GSH, GPx, lipid peroxidation, vitamin A and vitamin E) in rainbow trout (RNTR) and brook trout (BKTR) collected from reference and Se‐exposed streams. The physiological stress response was not impaired (cortisol secretory capacity unchanged); although there were species differences in plasma cortisol and plasma glucose levels. Liver GSH, GPx and vitamin levels were higher in RNTR than BKTR, but lipid peroxidation levels were not different. The elevated GSH reserves may make RNTR more sensitive to Se‐induced lipid peroxidation, but this may be offset by the RNTR's higher antioxidant (GPx and vitamin) levels. Species‐specific biochemical differences may mediate differences in Se sensitivity and be used in aquatic Se risk assessments. Copyright © 2009 John Wiley & Sons, Ltd.     

Copper toxicology,oxidative stress and inflammation using zebrafish as experimental model

Copper is an essential micronutrient and a key catalytic cofactor in a wide range of enzymes. As a trace element, copper levels are tightly regulated and both its deficit and excess are deleterious to the organism. Under inflammatory conditions, serum copper levels are increased and trigger oxidative stress responses that activate inflammatory responses. Interestingly, copper dyshomeostasis, oxidative stress and inflammation are commonly present in several chronic diseases. Copper exposure can be easily modeled in zebrafish; a consolidated model in toxicology with increasing interest in immunity‐related research. As a result of developmental, economical and genetic advantages, this freshwater teleost is uniquely suitable for chemical and genetic large‐scale screenings, representing a powerful experimental tool for a whole‐organism approach, mechanistic studies, disease modeling and beyond. Copper toxicological and more recently pro‐inflammatory effects have been investigated in both larval and adult zebrafish with breakthrough findings. Here, we provide an overview of copper metabolism in health and disease and its effects on oxidative stress and inflammation responses in zebrafish models. Copper‐induced inflammation is highlighted owing to its potential to easily mimic pro‐oxidative and pro‐inflammatory features that combined with zebrafish genetic tractability could help further in the understanding of copper metabolism, inflammatory responses and related diseases. Copyright © 2016 John Wiley & Sons, Ltd.     

熊果酸对动脉粥样硬化大鼠氧化应激和炎性反应的影响

目的 研究熊果酸(UA)对动脉粥样硬化(AS)大鼠氧化应激和炎性反应的抑制作用,并探讨其机制.方法 采用高脂饲料喂养结合腹腔注射VD3的方法建立早期AS大鼠模型,并分别灌胃给予UA(10、20、40 mg· kg-1· d-1)和辛伐他汀(SV, 1.8 mg· kg-1· d-1)进行干预,作为干预组,另设模型组和健康对照组(喂食正常饲料并腹腔注射生理盐水).采用比色法测定血清中抗氧化酶[超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、过氧化氢酶(CAT)]活性和丙二醛(MDA)、活性氧簇(ROS)含量;酶联免疫法(ELISA)测定血浆中炎性细胞因子[C反应蛋白(CRP)、肿瘤坏死因子-α(TNF-α)、白细胞介素-1β(IL-1β)、白细胞介素-6(IL-6)、白细胞介素-10(IL-10)]含量;苏木精-尹红(HE)染色观察主动脉形态结构改变并进行病变分级.结果 UA(20、40 mg· kg -1· d-1)同步干预组大鼠血清中 SOD、CAT 活性较模型组显著升高[(318.3 ±29.4)、(12.3 ±2.4)U· mL-1vs(249.3 ±25.1)、(9.3 ±1.7)U· mL-1],MDA、ROS含量显著降低[(31.2 ±5.1)vs(49.6 ±7.0) mmol· L-1和(291.3 ±31.8)vs(402.9 ±35.7)U· mL-1],且UA 40 mg· kg -1· d-1干预组GSH-Px活性显著升高[(809.3 ± 58.4)vs(676.1 ±48.5)U· mL-1];UA(20、40 mg· kg-1· d-1)同步干预组大鼠血浆中CRP、TNF-α、IL-1β、IL-6含量较模型组均显著降低,且UA 40 mg· kg-1· d-1干预组IL-10含量显著升高[(37.6 ±4.9)vs(23.9 ±3.2)ng· L-1];UA同步干预组大鼠主动脉形态结构改变较模型组明显改善、病变评分显著降低,其中以UA 40 mg· kg-1· d-1干预组效果最为显著.结论UA可能通过抑制氧化应激损伤和炎性反应而对AS大鼠起到一定保护作用.     

Antitumor efficacy and amelioration of oxidative stress by Trichosanthes dioica root against Ehrlich ascites carcinoma in mice

Context: Trichosanthes dioica Roxb. (Cucurbitaceae) is a dioecious climber, traditionally used in India for several medicinal purposes.

Objective: The present study assessed the hydroalcoholic extract of T. dioica root (TDA) for antitumor effect and antioxidant influence against Ehrlich ascites carcinoma (EAC) in Swiss albino mice.

Methods: Twenty four hours after intraperitoneal inoculation of tumor (EAC) cells in mice, TDA was administered at 5 and 10?mg/kg body weight daily for 9 consecutive days. On the 10th day, half of the mice were sacrificed for estimation of tumor proliferation, hematological, and liver antioxidant parameters viz. lipid peroxidation, reduced glutathione (GSH), glutathione S-transferase (GST), superoxide dismutase (SOD) and catalase (CAT); and the rest were kept alive for assessment of increase in life span. The antitumor effect of TDA was assessed by evaluating tumor weight, tumor volume, packed cell volume, viable and non-viable tumor cell counts, median survival time and percentage increase in life span of EAC bearing mice.

Results and discussion: TDA exhibited dose dependent and significant (p?<?0.001) decrease in tumor weight, tumor volume, packed cell volume and viable cell count and extended the life span of EAC bearing hosts. Hematological profiles were significantly (p?<?0.001) restored near to normal in TDA treated mice as compared to EAC control. TDA treatment significantly (p?<?0.001) modulated the aforesaid liver antioxidant parameters as compared to EAC control.

Conclusion: The present study demonstrated that TDA possessed promising antitumor efficacy in mice, plausibly mediated by amelioration of oxidative stress by multiple mechanisms.     

Total flavonoids of Epimedium ameliorates testicular damage in streptozotocin‐induced diabetic rats by suppressing inflammation and oxidative stress

Testicular damage is the anomaly that will often accompany diabetes mellitus. Thus, this study aimed to investigate the role that total flavonoids of Epimedium (TFE) played against streptozotocin (STZ)‐induced diabetic testicular dysfunction and to elucidate the mechanism of action. The diabetic rat model was induced by vein injection of STZ in healthy rats. Thirty male healthy Spraque‐Dawley rats were randomly divided into following groups: the control group, the diabetic group, and the diabetic + TFE group. Gastrointestinal administration begins at fifth week of TFE for 6 weeks. After TFE administration, all animals were euthanized. Testicular tissue samples and blood samples of rats were collected for histopathological examination and for determination of levels of various biomarkers including blood glucose, testosterone, testicular enzymes, and oxidative stress indicators. All testes were weighted to calculate the testicular organ index. Hematoxylin‐eosin staining was used for observing the testis and epididymis pathological changes. Protein expression (monocyte chemoattractant protein‐1, transforming growth factor‐beta‐1, interleukin‐6, and 3‐beta‐hydroxysteroid dehydrogenase) was detected by immunohistochemistry and western blot techniques. There was a significant difference in the changes between the diabetes group and the control group. As a result of treat with TFE, the blood glucose decreased but there was no significant difference, and other indicators showed significant improvement. TFE may protect against STZ‐induced testicular injury by suppressing inflammation and oxidative stress.     

Nanoparticles from photocopiers induce oxidative stress and upper respiratory tract inflammation in healthy volunteers

Abstract

Photocopiers emit large quantities of nanoparticles (NPs); however, their toxicological properties have not been studied. Here we investigate for the first time early human responses following a day's exposure to NPs from photocopiers. Nine healthy subjects spent 6 h at a busy photocopy centre on 2–3 randomly selected days. Matched nasal lavage and urine samples were collected before and at different time points post-exposure. Nasal lavage samples were analysed for 14 cytokines, inflammatory cells and total protein. Urine samples were analysed for 8-hydroxydeoxyguanosine (8-OH-dG). Exposure assessment was conducted using a suite of instruments. The mean total particle number on exposure days was >5 times higher than background, with size distributions in nanoscale range (peak 30–40 nm). Following exposure, 8-OH-dG and several pro-inflammatory cytokines were elevated 2–10 folds compared with pre-exposure levels and remained elevated for up to 36 h. We conclude that NPs from photocopiers induce upper airway inflammation and oxidative stress.     

Specific antioxidant reactions to oxidative stress promoted by natural organic matter in two amphipod species from Lake Baikal

Aquatic organisms are exposed to a variety of natural chemical stressors such as humic substances. The aim of this study was to investigate the mode of action of natural organic matter (NOM, roughly 80% of which is humic substances) on two freshwater amphipods from Lake Baikal, Eulimnogammarus verrucosus (Gerstf.) and Eulimnogammarus cyaneus (Dyb.), in order to assess the potential oxidative stress of NOM impact. Chosen as oxidative stress markers were lipid peroxidation and cell internal hydrogen peroxide level as well as peroxidase, catalase, and glutathione S-transferase activities. Exposure of amphipods to NOM caused a significant increase in lipid peroxidation but a concomitant decrease in hydrogen peroxide concentration, and peroxidase and (to a lesser degree) glutathione S-transferase activities. An interim increase of catalase activity was observed. A possible reason for the decrease in major antioxidant enzyme activity is exhaustion of the reservoir of reduced substrates in the first stage of the antioxidant defense reaction. Despite the inhibition of major antioxidant enzymes, the studied amphipods were able to successfully resist the NOM oxidative impact and, at low NOM concentrations, to combat lipid peroxidation processes.     

Evidence for cigarette smoke-induced oxidative stress in the rat pancreas

Background/aims: Recent findings with a rodent model of cigarette smoke inhalation revealed a causal relationship between chronic exposure to cigarette smoke and the development of pancreatitis. The present study was conducted to ascertain whether cigarette smoke induces oxidative stress in the rat pancreas concurrently with inflammation.

Methodology: Rats (six per treatment group) were treated for 0, 3, 6, 9, or 12 weeks with cigarette smoke (0.7?mg/L). Pancreatic tissues were examined for histological and pathological alterations and serum for changes in interleukin-6 concentration. Pancreatic expression and localization of α-smooth muscle actin, transforming growth factor-β1, and collagen-1 were determined as measures of progressive inflammation/fibrosis. Pancreatic superoxide dismutase and glutathione peroxidase activities and malondialdehyde content were measured as indices of oxidative stress.

Results: Inflammatory cell infiltration and ductal hyperplasia were detected in pancreata after 12 weeks of treatment with cigarette smoke. The serum interleukin-6 concentration increased significantly and pancreatic glutathione peroxidase activity declined significantly after 12 weeks of treatment. No other significant changes were observed.

Conclusions: Pancreata of rats exposed chronically to cigarette smoke exhibit inflammation concurrently with suppression of glutathione peroxidase activity. These observations favor a role for oxidative stress in the induction of pancreatitis associated with chronic cigarette smoke inhalation.     

Genotoxicity assessment and oxidative stress responses in freshwater African catfish Clarias gariepinus exposed to fenthion formulations

Fenthion is one of the most widely used organophosphate insecticides for the control of many varieties of pests in Nigeria. The genotoxic effect of the pesticide was evaluated in the blood erythrocytes of Clarias gariepinus using the micronucleus (MN) test. The oxidative stress parameters were also studied in the liver and gill tissues. Fish were exposed to 2.0, 4.0, and 8.0?mgL^?1 of fenthion and sampling was done on days 1, 7, 14, 21 and after 7-day recovery. Micronuclei induction was highest (7.55) on day 14 at all concentrations in the peripheral blood cells. Oxidative stress was evidenced by increased lipid peroxidation (LPO). Maximum LPO values of 62.47% and 71.17% were observed in the gill and liver tissues respectively in C. gariepinus exposed to 8.0?mgL^?1 concentration of fenthion. There were alterations in the values of reduced glutathione (GSH), glutathione reductase (GR), glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT) during the exposure and recovery periods. The 7-day recovery period was not adequate to eliminate fenthion-induced changes as LPO, CAT, and GR activity remain elevated. However, MN frequency and activity of SOD, GSH, and GPx (except at 8.0?mgL^?1) recovered. The present findings give further credence on the integrated use of MN test and oxidative stress parameters in risk assessment of pollutants in aquatic ecosystem.     

d-α-生育酚对乙醇引发的肝脏氧化应激的影响

目的观察d-α-生育酚对乙醇诱发的小鼠肝脏氧化应激的影响并探讨其机制。方法昆明种小鼠每天给予2.4g.kg-1bw乙醇后,再给予3个不同剂量的d-α-生育酚(25、50、100mg·kg-1bw.d-1),同时设正常对照组和乙醇对照组(乙醇2.4g·kg-1bw.d-1),连续灌胃60d后,测定肝脏超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、Na+,K+-ATP酶(Na+,K+-ATPase)、Ca2+,Mg2+-ATP酶(Ca2+,Mg2+-ATPase)、谷胱甘肽-S转移酶(GST)活力及丙二醛(MDA)的含量。结果小鼠摄入乙醇60d后,肝脏氧化应激水平明显增高。除Ca2+,Mg2+-ATPase以外,其余各项指标与正常对照组相比,差异均有显著性(P<0.05)。50mg·kg-1bw.d-1d-α-生育酚干预后,与乙醇对照组相比,GSH-Px、SOD、GST、Na+,K+-ATPase活力明显升高,MDA含量显著下降。其中,GSH-Px、Na+,K+-ATPase、MDA等3个指标在25mg·kg-1bw.d-1d-α-生育酚干预时亦出现同样的变化。结论适宜剂量的d-α-生育酚可以通过直接抑制脂质过氧化对乙醇诱发的肝脏氧化应激起保护作用。