Acephate induced oxidative damage in erythrocytes

The effect of oral administration of acephate (360 mg/kg body weight), for 15 days, daily, was investigated on the erythrocytes of male rats. Activities of acetyl cholinesterase and glucose-6-phosphate dehydrogenase decreased, while those of glutathione-s-transferase and glutathione reductase increased. Decreased glutathione content and increased lipid peroxidation suggest that there was increased oxidative stress in the erythrocytes of treated animals. Increased cholesterol/phospholipid ratio in the erythrocyte membranes and morphological changes in RBCs (scanning electron microscopy studies) were observed in acephate treated animals. The results clearly suggest that acephate induced oxidative stress in erythrocytes leads to morphological changes.     

Effect of melatonin on brain oxidative damage induced by traumatic brain injury in immature rats

Progressive compromise of antioxidant defenses and free radical-mediated lipid peroxidation, which is one of the major mechanisms of secondary traumatic brain injury (TBI), has also been reported in pediatric head trauma. In the present study, we aimed to demonstrate the effect of melatonin, which is a potent free radical scavenger, on brain oxidative damage in 7-day-old rat pups subjected to contusion injury. Whereas TBI significantly increased thiobarbituric acid reactive substances (TBARS) levels, there was no compensatory increase in the antioxidant enzymes such as superoxide dismutase (SOD) and glutathione peroxidase (GPx) 24 hours after TBI in 7-day-old rats. Melatonin administered as a single dose of 5 mg/kg prevented the increase in TBARS levels in both non-traumatized and traumatized brain hemispheres. In conclusion, melatonin protects against oxidative damage induced by TBI in the immature brain.     

Phosphine-induced oxidative damage in rats: attenuation by melatonin

Phosphine (PH(3)), from hydrolysis of aluminum, magnesium and zinc phosphide, is an insecticide and rodenticide. Earlier observations on PH(3)-poisoned insects, mammals and a mammalian cell line led to the proposed involvement of oxidative damage in the toxic mechanism. This investigation focused on PH(3)-induced oxidative damage in rats and antioxidants as candidate protective agents. Male Wistar rats were treated ip with PH(3) at 2 mg/kg. Thirty min later the brain, liver, and lung were analyzed for glutathione (GSH) levels and lipid peroxidation (as malondialdehyde and 4-hydroxyalkenals) and brain and lung for 8-hydroxydeoxyguanosine (8-OH-dGuo) in DNA. PH(3) caused a significant decrease in GSH concentration and elevation in lipid peroxidation in brain (36-42%), lung (32-38%) and liver (19-25%) and significant increase of 8-OH-dGuo in DNA of brain (70%) and liver (39%). Antioxidants administered ip 30 min before PH(3) were melatonin, vitamin C, and beta-carotene at 10, 30, and 6 mg/kg, respectively. The PH(3)-induced changes were significantly or completely blocked by melatonin while vitamin C and beta-carotene were less effective or inactive. These findings establish that PH(3) induces and melatonin protects against oxidative damage in the brain, lung and liver of rats and suggest the involvement of reactive oxygen species in the genotoxicity of PH(3).     

Ameliorative effect of supplementation with l-glutamine on oxidative stress,DNA damage,cell viability and hepatotoxicity induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin in rat hepatocyte cultures

The most potent of the dioxins, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), is a persistent and ubiquitous environmental contaminant. And the health impact of exposure to TCDD is of great concern to the general public. Recent data indicate that l-glutamine (Gln) has antioxidant properties and may influence hepatotoxicity. The objective of the present study was undertaken to explore the effectiveness of Gln in alleviating the hepatotoxicity of TCDD on primary cultured rat hepatocytes. Gln (0.5, 1 and 2 mM) was added to cultures alone or simultaneously with TCDD (0.005 and 0.01 mM). The hepatocytes were treated with TCDD and Gln for 48 h. Then cell viability was detected by [3-(4,5-dimethyl-thiazol-2-yl) 2,5-diphenyltetrazolium bromide] (MTT) assay and lactate dehydrogenase (LDH) release, while total antioxidant capacity (TAC), total glutathione (TGSH) and total oxidative stress (TOS) levels were determined to evaluate the oxidative injury. The DNA damage was also analyzed by liver micronucleus assay (MN) and 8-oxo-2-deoxyguanosine (8-OH-dG). The results of MTT and LDH assays showed that TCDD decreased cell viability but not l-glutamine. TCDD also increased TOS level in rat hepatocytes and significantly decreased TAC and TGSH levels. On the basis of increasing doses, the dioxin in a dose-dependent manner caused significant increases of micronucleated hepatocytes (MNHEPs) and 8-OH-dG as compared to control culture. Whereas, in cultures exposured with Gln alone, TOS levels were not changed and TAC and TGSH together were significantly increased in dose-dependent fashion. The presence of Gln with TCDD modulated the hepatotoxic effects of TCDD on primary hepatocytes cultures. Noteworthy, Gln has a protective effect against TCDD-mediated DNA damages. As conclusion, we reported here an increased potential therapeutic significance of l-glutamine in TCDD-mediated hepatic injury for the first time.     

Radio-protective effects of melatonin against irradiation-induced oxidative damage in rat peripheral blood

During radiotherapy, ionizing irradiation interacts with biological systems to produce free radicals, which attacks various cellular components. The hematopoietic system is well-known to be radiosensitive and its damage may be life-threatening. Melatonin synergistically acts as an immunostimulator and antioxidant. In this study we used a total of 120 rats with 20 rats in each group. Group 1 did not receive melatonin or irradiation (Control group), Group 2 received only 10 mg/kg melatonin (Mel group), Group 3 exposed to dose of 2 Gy irradiation (2 Gy Rad group), Group 4 exposed to 8 Gy irradiation (8 Gy Rad group), Group 5 received 2 Gy irradiation plus 10 mg/kg melatonin (Mel +2 Gy Rad group) and Group 6 received 8 Gy irradiation plus 10 mg/kg melatonin (Mel+8 Gy Rad group). Following exposure to radiation, five rats from each group were sacrificed at 4, 24, 48 and 72 h. Exposure to different doses of irradiation resulted in a dose-dependent decline in the antioxidant enzymes activity and lymphocyte count (LC) and an increase in the nitric oxide (NO) levels of the serum. Pre-treatment with melatonin (10 mg/kg) ameliorates harmful effects of 2 and 8 Gy irradiation by increasing lymphocyte count(LC) as well as antioxidant enzymes activity and decreasing NO levels at all time-points. In conclusion 10 mg/kg melatonin is likely to be a threshold concentration for significant protection against lower dose of 2 Gy gamma irradiation compared to higher dose of 8 Gy. Therefore, it seems that radio-protective effects of melatonin are dose-dependent.     

Protective action of melatonin against oxidative DNA damage: chemical inactivation versus base-excision repair

Melatonin is a hormone-like substance that has a variety of beneficial properties as regulator of the circadian rhythm and as anti-inflammatory and anti-cancer agent. The latter activity can be linked with the ability of melatonin to protect DNA against oxidative damage. It may exert such action either by scavenging reactive oxygen species or their primary sources, or by stimulating the repair of oxidative damage in DNA. Since such type of DNA damage is reflected in oxidative base modifications that are primarily repaired by base-excision repair (BER), we tried to investigate in the present work whether melatonin could influence this DNA-repair system. We also investigated the ability of melatonin to inactivate hydrogen peroxide, a potent source of reactive oxygen species. Melatonin at 50 microM and its direct metabolite N(1)-acetyl-N(2)-formyl-5-methoxykynuramine reduced DNA damage induced by hydrogen peroxide at approximately the same ratio. Melatonin stimulated the repair of DNA damage induced by hydrogen peroxide, as assessed by the alkaline comet assay. However, melatonin at 50 microM had no impact on the activity in vitro of three glycosylases playing a pivotal role in BER: Endo III, Fpg and ANPG 80. On the other hand, melatonin chemically inactivated hydrogen peroxide, reducing its potential to damage DNA. And finally, melatonin did not influence the repair of an a-basic (AP) site by cellular extracts, as was evaluated by a functional BER assay in vitro. In conclusion, melatonin can have a protective effect against oxidative DNA damage by chemical inactivation of a DNA-damaging agent as well as by stimulating DNA repair, but key factors in BER, viz. glycosylases and AP-endonucleases, do not seem to be affected by melatonin. Further study with other components of the BER machinery and studies aimed at other DNA-repair systems are needed to clarify the mechanism underlying the stimulation of DNA repair by melatonin.     

己烯雌酚对成年雄性金色中仓鼠的生殖毒性与氧化损伤的关系

为研究环境雌激素己烯雌酚(DES)的生殖毒性与活性氧(ROS)的关系,连续7天给成年金色中仓鼠皮下注射0、0.01、0.1、1mg/kgBWDES,称量睾丸重量、计算睾丸相对重量,光镜观察睾丸组织结构的变化,分光光度法检测睾丸组织和血浆中超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、总抗氧化能力(T-AOC)和丙二醛(MDA)的含量。结果表明:1mg/kgBWDES导致睾丸萎缩、重量下降,曲细精管中生精细胞排列紊乱,管腔内几乎没有成熟精子;随着DES剂量的增加,睾丸组织中SOD、GSH-Px和T-AOC含量显著下降,MDA显著上升。提示DES的生殖毒性与ROS密切相关,DES通过降低抗氧化酶水平,增加ROS含量,干扰生精细胞正常功能,导致细胞死亡,表明氧化损伤可能是环境雌激素生殖毒性的作用机理之一。     

Antioxidant effects of melatonin and coenzyme Q10 on oxidative damage caused by single-dose ochratoxin A in rat kidney

In the study, the effects of relatively high single-dose of Ochratoxin A (OTA) and the antioxidant effects of Melatonin (Mel) and Coenzyme Q10 (CoQ10) on OTA-induced oxidative damages in rats were investigated. A total of 28 male Sprague-Dawley rats were divided into four groups of 7 rats each: Control, OTA, Mel+OTA and CoQ10+OTA groups. Malondialdehyde (MDA) levels in the plasma and glutathione (GSH) levels in whole blood were measured; kidneys (for histological inspection and for apoptosis detection by TUNEL method) and bone marrow samples (for chromosome aberration and mitotic index) were taken. The rats in the OTA group showed limited degeneration of tubular cells. In some tubules karyomegaly, desquamated cells and vacuolization were observed by light microscopy. Mel and CoQ10 treatment significantly reduced the severity of the lesions. MDA levels of the OTA group were significantly higher than the control, OTA+Mel and OTA+CoQ10 groups, while GSH levels were significantly lower than the control, OTA+Mel and OTA+CoQ10 groups. Higher incidences of apoptotic bodies were observed in the kidneys of the OTA group although OTA administration did not significantly change the incidence of apoptotic bodies when compared to the control and antioxidant administrated groups. Although the percentage of the mitotic index was lowest in the OTA group, no statistical difference was found among the groups. Additionally, OTA had no numerical and structural significant effects on chromosomes. It was observed that single-dose OTA administration caused oxidative damages in rat kidney and Mel or CoQ10 treatment appeared to ameliorate the OTA-induced tissue injuries.     

褪黑素对顺铂的听觉中枢毒性的影响

目的：研究顺铂的中枢听觉毒性以及褪黑素对其的保护作用。方法：用顺铂和不同浓度褪黑素分别在豚鼠左右腹腔注射7d后,用分光光度计测量听皮层脑组织LDH活力、MDA、NO含量。结果：顺铂注射7d后各组的体重均下降,其中以单独注射顺铂组和10mg·kg^-1·d^-1褪黑素加顺铂组下降趋势最明显,较处理前有显著差异（P〈0．01）。顺铂组动物听皮层LDH活力水平明显高于生理盐水组（P〈0．01）;褪黑索能显著降低顺铂引起的听皮层脑组织中的LDH增高（P〈0．05）。豚鼠腹腔注射顺铂7d后听皮层MDA含量较腹腔注射生理盐水组明显增高（P〈0．01）;同时腹腔注射褪黑素能降低听皮层组织MDA含量（P〈0．05）。各药物作用后听皮层的NO含量变化统计学比较无显著性意义。结论：腹腔注射顺铂能够作用于听皮层引起细胞损伤。褪黑素对顺铂所致的听皮层细胞损伤有防护作用,机制可能与其抗自由基作用有关。     

Peroxidative membrane damage in human erythrocytes induced by a concerted action of iodoacetate, vanadate and ferricyanide

Human erythrocytes incubated without substrate in the presence of iodoacetate (0.2 mM), vanadate (0.5 mM) and ferricyanide (5 mM) form aqueous membrane leaks of equivalent radii of 0.5-0.8 nm leading to complete colloid-osmotic lysis within 180 min. All three components are indispensable for the effect. Inosine but not glucose markedly enhances the rate of hemolysis. These effects are due to oxidative damage, as indicated by concomitant destruction of polyunsaturated fatty acids and suppression of both effects by radical scavengers. Hemoglobin is not oxidized under these conditions. GSH and membrane SH levels remain almost normal, and no crosslinking or irreversible aggregation of membrane proteins is observed. In the absence of O2 no membrane damage can be observed. It is proposed that radical formation originates from reduction of O2 by NADPH, analogous to processes described in microsomal membranes. NADH seems not to be involved, since leak formation occurs in spite of the blockage of NADH formation by iodoacetate. Vanadate and ferricyanide are probably required to amplify the peroxidative reaction sufficiently to overcome the cellular antioxidative capacity.     

Protective effect of melatonin on contractile activity and oxidative injury induced by ischemia and reperfusion of rat ileum

Free radicals derived from molecular oxygen have been reported to be responsible for changes in motility and mucosal damage observed in intestinal ischemia-reperfusion injury. Melatonin has been considered as an antioxidant that prevents injuries resulted from I/R in various tissues. The present study was designed to determine the effect of melatonin on the contractile responses of acetylcholine (Ach) and KCl, on malondialdehyde (MDA), a product of lipid peroxidation, and reduced glutathione (GSH) levels and to assess histopathological changes in the smooth muscle of terminal ileum subjected to ischemia-reperfusion. The intestinal ischemia-reperfusion was induced by occlusion of superior mesenteric artery of rat for 30 min, followed by a period of reperfusion for 3 h. Melatonin at doses of 10 or 50 mg/kg was administered via the tail vein in 5 min prior to reperfusion. Following reperfusion, segments of terminal ileum were rapidly taken and transferred into isolated organ bath and responses to Ach and KCl were recorded. Samples of terminal ileum were also taken for measuring the MDA and GSH levels. EC50 values of these contracting substances were seriously reduced in the ischemia-reperfusion group compared to that of the sham-operated control group. The decreased contraction response to Ach and KCl was significantly ameliorated by a dosage of 50 mg/kg of melatonin, while not by a dosage of 10 mg/kg. Similar pattern of the effect was observed in the tissue levels of MDA and GSH as well as in histological improvement. Melatonin appeared to be restoring the amounts of tissue MDA and GSH back to about control levels. These results suggest that the high dose of melatonin not only physiologically but also biochemically and morphologically could be useful to normalize contractility injured by oxidative stress in intestinal ischemia-reperfusion.     

Oxidative damage induced by chromium (VI) in rat erythrocytes: protective effect of selenium

Excess chromium (Cr) exposure is associated with various pathological conditions including hematological dysfunction. The generation of oxidative stress is one of the plausible mechanisms behind Cr-induced cellular deteriorations. The efficacy of selenium (Se) to combat Cr-induced oxidative damage in the erythrocytes of adult rats was investigated in the current study. Female Wistar rats were randomly divided into four groups of six each: group I served as controls which received standard diet, group II received in drinking water K₂Cr₂O₇ alone (700 ppm), group III received both K₂Cr₂O₇ and Se (0.5 Na₂SeO₃ mg/kg of diet), and group IV received Se (0.5 mg/kg of diet) for 3 weeks. Rats exposed to K₂Cr₂O₇ showed an increase of malondialdehyde and protein carbonyl levels and a decrease of sulfhydryl content, glutathione, non-protein thiol, and vitamin C levels. A decrease of enzyme activities like catalase, glutathione peroxidase, and superoxide dismutase activities was also noted. Co-administration of Se with K₂Cr₂O₇ restored the parameters cited above to near-normal values. Therefore, our investigation revealed that Se was a useful element preventing K₂Cr₂O₇-induced erythrocyte damages.     

Thiol oxidation induced by oxidative action of adriamycin

To clarify the mechanism of the cardiotoxic action of adriamycin (ADM), the participation of free radicals from ADM in cardiotoxicity was investigated through the protective action of glutathione (GSH) or by using electron spin resonance (ESR). Oxidation of ADM by horseradish peroxidase and H₂O₂ (HRP-H₂O₂) was blocked by GSH concentration dependently. Inactivation of creatine kinase (CK) induced during interaction of ADM with HRP-H₂O₂ was also protected by GSH. Other anthracycline antitumor drugs that have a p-hydroquinone structure in the B ring also inactivated CK, and GSH inhibited the inactivation of CK. These results suggest that ADM was activated through oxidation of the p-hydroquinone in the B ring by HRP-H₂O₂. Although ESR signals of the oxidative ADM B ring semiquinone were not detected, glutathionyl radicals were formed during the interaction of ADM with HRP-H₂O₂ in the presence of GSH. ADM may be oxidized to the ADM B ring semiquinone and then reacts with the SH group. However, ESR signals of ADM C ring semiquinone, which was reductively formed by xanthine oxidase (XO) and hypoxanthine (HX) under anaerobic conditions, were not diminished by GSH, but they completely disappeared with ferric ion. These results indicate that oxidative ADM B ring semiquinones oxidized the SH group in CK, but reductive ADM C ring semiquinone radicals may participate in the oxidation of lipids or DNA and not of the SH group.     

Ameliorative effect of berberine on renal damage in rats with diabetes induced by high-fat diet and streptozotocin

Berberine (BBR) is one of the main constituents in Rhizoma coptidis and it has widely been used for the treatment of diabetic nephropathy. The aims of the study were to investigate the effects and mechanism of action of berberine on renal damage in diabetic rats. Diabetes and hyperglycaemia were induced in rats by a high-fat diet and intraperitoneal injection of 40 mg/kg streptozotocin (STZ). Rats were randomly divided into 5 groups, such as i) control rats, ii) untreated diabetic rats iii) 250 mg/kg metformin-treated, iv and v) 100 and 200 mg/kg berberine-treated diabetic rats and treated separately for 8 weeks. The fasting blood glucose, insulin, total cholesterol, triglyceride, glycosylated hemoglobin were measured in rats. Kidneys were isolated at the end of the treatment for histology, Western blot analysis and estimation of malonaldehyde (MDA), superoxide dismutase (SOD) and renal advanced glycation endproducts (AGEs). The results revealed that berberine significantly decreased fasting blood glucose, insulin levels, total cholesterol, triglyceride levels, urinary protein excretion, serum creatinine (Scr) and blood urea nitrogen (BUN) in diabetic rats. The histological examinations revealed amelioration of diabetes-induced glomerular pathological changes following treatment with berberine. In addition, the protein expressions of nephrin and podocin were significantly increased. It seems likely that in rats berberine exerts an ameliorative effect on renal damage in diabetes induced by high-fat diet and streptozotocin. The possible mechanisms for the renoprotective effects of berberine may be related to inhibition of glycosylation and improvement of antioxidation that in turn upregulate the expressions of renal nephrin and podocin.     

Prophylactic action of melatonin against cyclophosphamide-induced oxidative stress in mice

The present study investigated the prophylactic influence of melatonin against cyclophosphamide-induced oxidative stress in mouse tissues. Lipid peroxidation, reduced glutathione (GSH), glutathione disulphide (GSSG), glutathione peroxidase (GSH-Px) and serum phosphatase levels were analyzed in brain, spleen liver, lungs, kidney and testes. Fifteen days oral administration with melatonin (0.1 mg/kg bw per day) before treatment checked the augmentation of the level of lipid peroxidation, blood GSSG and acid phosphatase caused by an acute treatment with a radiomimetic drug, cyclophosphamide (75 mg/kg bw). Cyclophosphamide-induced depletion in the level of GSH, GSH-Px and alkaline phosphatase was made up statistically significant by chronic melatonin administration given orally. The results indicate the antioxidative properties of melatonin resulting into its prophylactic property against the cyclophosphamide-induced biochemical alterations. The finding support the idea that melatonin is a potent free-radical scavenger and antioxidant.     

Copper-specific damage in human erythrocytes exposed to oxidative stress

Ascorbate and complexes of Cu(II) and Fe(III) are capable of generating significant levels of oxygen free radicals. Exposure of erythrocytes to such oxidative stress leads to increased levels of methemoglobin and extensive changes in cell morphology. Cu(II) per mole is much more effective than Fe(III). However, isolated hemoglobin is oxidized more rapidly and completely by Fe(III)- than by Cu(II)-complexes. Both Fe(III) and Cu(II) are capable of inhibiting a number of the key enzymes of erythrocyte metabolism. The mechanism for the enhanced activity of Cu(II) has not been previously established. Using intact erythrocytes and hemolysates we demonstrate that Cu(II)-, but not Fe(III)-complexes in the presence of ascorbate block NADH-methemoglobin reductase. Complexes of Cu(II) alone are not inhibitory. The relative inability of Fe(III)-complexes and ascorbate to cause methemoglobin accumulation is not owing to Fe(III) association with the membrane, or its failure to enter the erythrocytes. The toxicity of Cu(II) and ascorbate appears to be a result of site-specific oxidative damage of erythrocyte NADH-methemoglobin reductase and the enzyme's subsequent inability to reduce the oxidized hemoglobin.     

Protective effect of Indian honey on acetaminophen induced oxidative stress and liver toxicity in rat

The present study was undertaken to investigate the protective effect of Indian honey on acetaminophen induced oxidative stress and liver damage in rat. Honey serves as a source of natural medicine, which is effective to reducing the risk of heart disease, liver toxicity and inflammatory processes. The hepatoprotective activity of the Indian honey was determined by assessing levels of Serum transaminases, ALP and total bilirubin. Finally, the effects of the test substances on the antioxidant enzymes of the liver were also studied by assessing changes in the level of reduced glutathione, glutathione peroxidase, catalase and superoxide dismutase. Serum transaminase, ALP and total bilirubin level were significantly elevated and the antioxidant status in liver such as activities of SOD, CAT, GPx and the levels of GSH were declined significantly in APAP alone treated animals. Pretreatment with honey and silymarin prior to the administration of APAP significantly prevented the increase in the serum levels of hepatic enzyme markers and reduced oxidative stress. The histopathological evaluation of the livers also revealed that honey reduced the incidence of liver lesions induced by APAP. Results suggest that the Indian honey protects liver against oxidative damage and it could be used as an effective hepatoprotector against APAP induced liver damage.     

Ameliorative role of Ziziphus spina-christi leaf extracts against hepatic injury induced by Plasmodium chabaudi infected erythrocytes

One of the most common deadliest parasitic diseases is Malaria. The biology and the pathogenesis of this fascinating parasite are not yet fully understood which make discovering effective alternative drugs a challenging task. Moreover, the emergence of resistant strains added an additional burden in the journey of malaria elimination. Traditional medicine used to be an alternative therapy choice owing to the presence of potent natural products. Ziziphus spina-christi (L.) considered being one of the common potent natural plant in gulf region and other nations. Therefore, this study designed to evaluate the ameliorative role of Z. spina-christi leaf extracts (ZSCLE) against Plasmodium chabaudi-induced hepatic injury. The study involved three groups were as follows; a vehicle control group, infected with 10⁶P. chabaudi-parasitized erythrocytes group and ZSCLE treated-infected mice with 10⁶P. chabaudi-parasitized erythrocytes group. The results showed a remarkable reduction of parasitemia level and notable reverse of the anemic picture among ZSCLE treated-infected mice. The effects of ZSCLE on the liver functions enzymes and on the histopathological pictures of liver were significant. It could be concluded that Z. spina-christi leaf extracts have a protective role against Plasmodium infection that also marked through significant restoration of hepatic oxidative markers.