滞育发动前家蚕滞育性与非滞育性卵的谷胱甘肽氧化还原循环状态分析

为了调查滞育和非滞育性家蚕卵的谷胱甘肽氧化还原循环在滞育发动前是否存在差异,利用分光光度法检测滞育发动前(25℃中蚕卵产下后0～24 h)滞育与非滞育蚕卵的谷胱甘肽含量和相关代谢酶活性。滞育发动前,滞育性家蚕卵中的还原型谷胱甘肽(GSH)含量、氧化型谷胱甘肽(GSSG)含量、总谷胱甘肽(GSH+2GSSG)含量和GSH/GSSG比值变化不显著,谷胱甘肽S-转移酶(GST)活性变化不显著,但硫氧还蛋白过氧化物酶(TPX)活性下降23%,谷胱甘肽还原酶(GR)活性升高57%;非滞育性家蚕卵中的GSH含量及TPX和GST活性变化不显著,但GSSG含量升高61%,GSH+2GSSG含量升高41%,GSH/GSSG比值下降33%,GR活性下降16%。与非滞育性家蚕卵相比,滞育发动前滞育性家蚕卵中的GSH含量、GSSG含量和GSH+2GSSG含量较低,GSH/GSSG比值较高,TPX活性较低,GST活性无显著差异,GR活性较高。两种蚕卵中都未能检测到谷胱甘肽过氧化物酶(GPX)和硫氧还蛋白还原酶(TrxR)活性。结果表明,滞育发动前滞育性家蚕卵中较低的TPX活性和较高的GR活性共同导致较高的GSH/GSSG比值,使其谷胱甘肽氧化还原循环处于相对还原态。     

Antioxidant defence system of boar cauda epididymidal spermatozoa and reproductive tract fluids

Antioxidants secreted by the reproductive tract protect spermatozoa against the toxic effects of reactive oxygen species (ROS) after ejaculation. This study aimed at characterizing the level of antioxidant protection in boar cauda epididymidal spermatozoa and fluids of the cauda epididymidis, vesicular and prostate glands. Also, this study investigated the effect of a 5-h period of dialysis on the antioxidant capacity of boar seminal plasma. Superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione transferase (GST) and phospholipid hydroperoxide glutathione peroxidase (PHGPx) activities were monitored in the cauda epididymidal spermatozoa or reproductive tract fluids. Also, the concentrations of total glutathione (GSH + GSSG), L-ergothioneine (ERT) and l-ascorbate and the total antioxidant status (TAS) of the fluids were measured. It was found that the cauda epididymidal spermatozoa exhibited high SOD activity and relatively low activity of PHGPx. The relative amounts of GPx, GR and GST activities in the cauda epididymidal spermatozoa were negligible, whereas CAT activity was undetectable. Greater SOD activity was found in the fluids of the cauda epididymidis and prostate gland. Furthermore, the prostate gland fluid appeared to be the main source of CAT activity in the seminal plasma, whereas the highest level of GPx activity was derived from the cauda epididymidal fluid. The reproductive tract fluids exhibited negligible amounts of GR and GST activities. It seemed that the significant amounts of GSH + GSSG, ERT and L-ascorbate in the reproductive tract fluids could have an ameliorative effect on the level of TAS in the seminal plasma. Dialysis had a marked effect on the total antioxidant capacity of the seminal plasma, which was manifested in greater activity of SOD and GPx. The findings of this study confirmed that the scavenging potential of the seminal plasma is dependent on the contributions of different antioxidants, originating in various fluids of boar reproductive tract.     

Gill oxidative stress and histopathological biomarkers of pollution impacts in Nile tilapia from Lake Mariut and Lake Edku, Egypt

Various oxidative stress and histopathological biomarkers in gill tissues of Nile tilapia Oreochromis niloticus were investigated. Fish were collected from four sites that differ in their extent of pollution load, including heavy metals: the southeast basin (SEB), main basin (MB), and northwest basin (NWB) of Lake Mariut; and Boughaz El-Maadiya, a channel in Lake Edku. The oxidative stress biomarkers that were analyzed included lipid peroxidation (LPO), superoxide dismutase (SOD), catalase (CAT), and glutathione redox cycle enzymes (glutathione peroxidase [GPx] and glutathione reductase [GR]). Levels of reduced glutathione (GSH) were also evaluated. Gill morphology was analyzed by light microscopy and scanning electron microscopy (SEM). Gill LPO was significantly higher in gill tissues of fish collected from the more heavily contaminated MB (40.0%) and NWB (51.4%) sites than in gill samples from the less-contaminated (reference) site, the SEB. Gill LPO in fish from Lake Edku was intermediate but was not significantly higher (17.1%) than the reference. The activities of antioxidant enzymes and the redox-sensitive thiol compound GSH were significantly lower in gill samples from the disturbed sites than in samples from the reference site. Specifically, SOD in MB, NWB, and Lake Edku samples; CAT and GPx in NWB samples; and GR activity and GSH content in MB and NWB samples were lower than those in SEB samples. In most cases, gill tissues from Lake Edku fish had intermediate levels of antioxidants. The main histopathological alterations observed in gills were epithelial lifting, hyperplasia and hypertrophy of the respiratory epithelium, lamellar fusion, and aneurysms. In addition, SEM results demonstrated transformation of the surface structure of epithelial pavement cells. Pathological reactions in the gills of Nile tilapia were most severe at the MB and NWB sites. Our findings suggest that Nile tilapia responded differently according to the environmental stress index in each sampling area. This study is the first to report gill oxidative stress and histopathologies in Nile tilapia from Egyptian aquatic environments.     

Effects of dietary leucine on antioxidant activity and expression of antioxidant and mitochondrial‐related genes in longissimus dorsi muscle and liver of piglets

The study was conducted to investigate the effects of dietary leucine on antioxidant activity and expression of antioxidant‐ and mitochondrial‐related genes in longissimus dorsi muscle and liver of piglets. Three diets were formulated with different levels of supplemented leucine (0%, 0.25%, 0.5%). Results showed that supplementation of 0.25% leucine significantly increased antisuperoxide anion (ASA) and antihydroxyl radical (AHR) levels and activities of total superoxide dismutade (T‐SOD), glutathione peroxidase (GPx), glutathione S‐transferase (GST), and total antioxidant capacity (T‐AOC) in serum, longissimus dorsi muscle and liver of piglets as compared with the control group. The SOD2, catalase (CAT), GPx, GST, glutathione reductase (GR), and nuclear factor erythroid 2‐related factor 2 (Nrf2) mRNA levels in longissimus dorsi muscle and liver were significantly increased by 0.25% leucine supplementation. However, the malondialdehyde (MDA) content and the mRNA level of Kelch‐like ECH‐associated protein 1 (Keap1) exhibited an opposite tendency. Additionally, supplementation of 0.25% leucine significantly increased the mRNA levels of mitochondrial‐related genes in longissimus dorsi muscle and liver of piglets. Results suggested that supplementation of 0.25% leucine improved antioxidant activity and mitochondrial biogenesis and function of piglets, which was related to the increase in antioxidant enzymes activities and upregulation of expression of antioxidant‐ and mitochondrial‐related genes.     

Enzymatic antioxidant defense in isolated rat hepatocytes exposed to cadmium

The aim of the study was the evaluation of cadmium effects on the activity of antioxidant enzymes in rat hepatocytes. The studies were conducted with isolated rat hepatocytes incubated for 1 or 2 hours in a modified (deprived of carbonates with phosphates) Williams' E medium (MWE) in the presence of cadmium chloride (25, 50 and 200 microM). Hepatocytes incubated in the MWE medium without cadmium chloride were used as a control. The application of the modified Williams' E medium allowed for the appearance of cadmium compounds in a soluble form that is indispensable for suitable estimation of its toxic action. There were evaluated markers of the oxidative stress such as: concentration of thiobarbiturate reactive substances (TBARS)--proportional to the level of lipid peroxidation, concentration of reduced glutathione (GSH), and the activity of antioxidant enzymes, including superoxide dismutase (SOD1 and SOD2), catalase (CAT), total glutathione peroxidase (GSHPx), selenium--dependent glutathione peroxidase (SeGSHPx), glutathione transferase (GST) and glutathione reductase (GSHR). Alterations of antioxidant enzymes activity, the level of TBARS and GSH in isolated rat hepatocytes caused by cadmium in vitro, were shown to depend on the concentration and time of exposure of cells to this metal. The increased level of TBARS and GSH was observed as well as changes in the activity of antioxidant enzymes. The activity of SOD isoenzymes and CAT was increased, whereas GSHPx and GST were decreased. These results indicate that cadmium induces oxidative stress followed by alterations in the cellular antioxidant enzyme system in isolated rat hepatocytes.     

SO2对家蚕血淋巴中谷胱甘肽含量及相关酶活性的影响

通过分析在SO2胁迫下家蚕5龄幼虫血淋巴中谷胱甘肽(GSH)含量及相关酶活性的变化,探讨SO2对家蚕的毒理作用机制。当对家蚕5龄幼虫每天以40 mg/m3SO2熏气刺激6 h,蚕体血淋巴中的GSH含量显著降低,雄蚕GSH的平均含量为49.8μmol/L,雌蚕为41.0μmol/L,分别为对照的73.80%和55.76%,而谷胱甘肽硫-转移酶(GST)活性显著升高,雄蚕GST的平均活性为31.86 U/L,雌蚕为31.80 U/L,分别高于对照46.15%和27.30%。与此同时,γ-谷氨酰转肽酶(γ-GT)活性在蚕体中也有不同程度的升高,其中在雄蚕体内的变化极为显著;谷胱甘肽过氧化酶(GSH-Px)和谷胱甘肽合成酶系的活性在蚕体内均无显著变化。以上结果表明:SO2刺激可对家蚕血淋巴中的GSH含量及其相关酶的活性产生影响,且雌、雄蚕对SO2的敏感性不同;GSH含量的减少及其相关酶活性的上升,说明SO2对蚕体的毒害作用与其降低蚕体抗氧化物质水平、削弱抗氧化防御系统有关。     

还原型谷胱甘肽对氟中毒小鼠附睾的影响

试验旨在研究还原型谷胱甘肽（reduced glutathione,GSH）对氟中毒小鼠附睾的影响。将50只3周龄ICR雄性小鼠随机分为5组,分别为对照组和4组染氟组。对照组饮用蒸馏水,染氟组分别供给含100 mg/L NaF的蒸馏水,自由饮水30 d。之后在染氟组中选择3组每日分别灌胃200、400和800 mg/（kg·只）GSH,同时各组小鼠再自由饮含氟水30 d。试验结束后,摘取小鼠附睾进行活性氧（ROS）、丙二醛（MDA）、GSH含量及谷胱甘肽过氧化物酶（GPx）、谷胱甘肽硫转移酶（GSTs）和谷胱甘肽还原酶（GR）活性检测,同时制作石蜡切片,HE染色后进行组织形态结构分析。结果显示,与对照组相比,100 mg/L NaF组精子密度、精子活力、GSH含量、GPx和GR活性均显著下降（P<0.05）,而GSH添加组较100 mg/L NaF组均有所升高;100 mg/L NaF组精子畸形率、ROS和MDA含量较对照组均显著升高（P<0.05）,而GSH添加组较100 mg/L NaF组均降低,其中800 mg/kg GSH组效果明显。与对照组相比,100 mg/L NaF组附睾头、附睾体及附睾尾管腔厚度升高,管腔内精子数量下降;GSH添加组附睾头、附睾体及附睾尾的管腔厚度与管腔内精子数量都有所恢复,其中800 mg/kg GSH组效果较好。综上所述,添加GSH后氟中毒小鼠谷胱甘肽抗氧化系统酶活性有所升高,附睾组织形态结构一定程度上有所恢复,对附睾有一定的改善作用。     

不同体质量建鲤血清和组织中抗氧化指标的变化

本试验旨在研究建鲤(Cyprinus carpio var.Jian)幼鱼期(18～75 g)随体质量增加,机体和组织器官中抗氧化酶活性和非酶抗氧化物质含量以及抗超氧阴离子自由基能力(ASA)和抗羟自由基能力(AHA)的变化规律.试验选用均初体质量为(18.0±0.20)g的健康建鲤750尾,随机分成5组,每组3个重复,每个重复50尾.所有试验鱼饲喂相同的试验饲料,每隔14d称重取样1次,称重后,分别取血液、肝胰脏、肠道和肌肉组织测定抗氧化指标,共取5次.结果表明:血清、肝胰脏、肠道和肌肉中丙二醛和蛋白质羰基含量随体质量增加而显著降低(P＜0.05),分别在体质量达31.4和58.6g以后达到稳态(P＞0.05);ASA和AHA随体质量增加而显著增强(P＜0.05),均在体质量达40.1g以后达到稳态(P＞0.05);超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和谷胱甘肽过氧化物酶(GSH-Px)活性随体质量增加而显著提高(P＜0.05),均在体质量达40.1g以后达到稳态(P＞0.05);谷胱甘肽硫转移酶(GST)和谷胱甘肽还原酶(GR)活性随体质量增加而显著提高(P＜0.05),均在体质量达31.4g以后达到稳态(P＞0.05);还原型谷胱甘肽(GSH)含量随体质量增加而显著提高(P＜0.05),分别在体质量达31.4、31.4、31.4和58.6g以后达到稳态(P＞0.05).综上所述,建鲤幼鱼随体质量增加,血清和组织中SOD、CAT、GSH-Px和GST等抗氧化酶活性逐渐增强,低分子抗氧化物质GSH含量逐渐提高,从而使得ASA和AHA逐渐增强,脂质过氧化和蛋白质氧化产物含量逐渐降低,并最终达到稳态.     

Seasonal variation in testicular blood flow dynamics and their relation to systemic and testicular oxidant/antioxidant biomarkers and androgens in rams

The environmental temperature increased during summer and decreased during winter to the limits that might negatively affect animal and human reproduction. The responses of Egyptian rams to either hot or cold climatic conditions were studied in six mature rams subjected to weekly testicular Doppler ultrasonographic examination, blood sampling, seminal plasma collection and semen evaluation. The maximum environmental temperature and the relative humidity were used to classify the climatic condition according to the heat stress equation of sheep into hot months where temperature–humidity index (THI) was >26 (31.67 ± 0.54), and cold months where THI was <22 (18.39 ± 0.41). Testosterone, estradiol, superoxide dismutase (SOD), glutathione peroxidase (GPX) and lipid peroxide product (malondialdehyde, MDA) were measured in both blood and seminal plasma, while catalase (CAT) and reduced glutathione (GSH) were measured in blood and seminal plasma, respectively. Results revealed that, during the hot months, rams displayed significantly decreased testicular blood flow, increased seminal plasma MDA, decreased seminal plasma (SOD, GPx and GSH) and blood CAT antioxidant enzymes. The present study evidenced two novel findings: (a) the marked decrease in testicular blood flow volume, that is remarkable increase in both resistive index (RI) and pulsatility index (PI) values, during hot months could be negatively affected both seminal plasma enzymatic activities and seminal attributes, and (b) the SOD and GPx activities in seminal plasma of such animals were suitable predictive markers for seminal attribute evaluation.     

Interaction between the three frequently co‐occurring Fusarium mycotoxins in rats

To test the complex, acute biochemical effects of combined, naturally co‐occurring fusariotoxins, a 5‐day rat study was performed. Mycotoxin treatment was invented by intraperitoneal injection: FB₁ (F): 9 µg/animal/day (approx. 30 µg/kg bw/day), DON (D): 16.5 µg/animal/day (approx. 55 µg/kg bw/day) and ZEN (Z): 12.75 µg/animal/day (approx. 42.5 µg/kg bw/day). The binary groups (FB₁ and DON [FD], FB₁ and ZEN [FZ] and DON and ZEN [DZ]) as well as the ternary (FB₁, DON and ZEN [FDZ]) group were dosed at the same combined level as the individual mycotoxins. Body weight, feed intake and mortality were not affected by any of the treatments. FB₁ and DON in combination (FD) increased the plasma aspartate aminotransferase activity synergistically (compared to the individual FB₁ and DON). In the liver, both the total glutathione (GSH) and the glutathione peroxidase (GPx) activity were increased (p < 0.05) by the binary FB₁ and ZEN (FZ) and the DON and ZEN (DZ) groups as well as the ternary FB₁, DON and ZEA group (FDZ) compared to the control. The GSH level of the ternary group was significantly increased compared to the FB₁ group, whereas the GPx activity of the ternary group was significantly increased compared to all three the individual mycotoxin groups. The Bliss independence method revealed synergism between DON and ZEN (DZ), as well as FB₁ and DON (FD) on liver GPx activity. None of the toxins alone or in combination exerted strong genotoxicity on lymphocytes, neither on the gross histopathological characteristics. However, even at these low levels acute exposure of more than one of these mycotoxins (FB₁, DON and ZEN) affected metabolic and detoxification changes.     

Characteristics of Antioxidant Systems of Yellow Fraction of Red Deer's (Cervus elaphus L.) Semen During the Rutting Period

The objective of this study was to make the preliminary characterization of the antioxidant defence systems of the yellow fraction (YF) of red deer's (Cervus elaphus L.) semen during the rutting period. The semen was collected using artificial vagina (AV). The studies included spectrophotometric determination of antioxidant enzymes activities such as superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx). We also analysed the contents of low‐molecular antioxidants such as L‐glutathione (GSH + GSSG), L‐ascorbate (ASC) and total antioxidant status (TAS). Additionally, the samples were subjected to PAGE and stained for SOD and GPx activities. It was demonstrated that the yellow fraction exhibited activities of SOD and GPx, with the highest activities in September and October. CAT activity was not detected. Staining for the SOD and GPx activities confirmed three protein bands with SOD activity and one protein band with GPx activity. The content of GSH + GSSG was similar in trials dating from October to December contrary to the content of ASC which was high in samples from September and October. The stable rate of TAS was observed during the whole rutting period. The results of this study showed that the YF of red deer semen is equipped with basic battery of antioxidant enzymes comprising SOD and GPx, with the supporting role of GSH + GSSG and ASC. Moreover, the samples obtained at the peak of the rutting period occurring from September to October had the highest enzymatic activity in comparison with remaining months of the rutting period, which contributed to the high quality of the semen by preventing it from the formation of oxidative stress during the short period of intense sexual activity of male red deer. The better understanding of the mechanisms of antioxidant defence systems in the YF of deer's semen may contribute to the potential use of this fraction in technology of wild ruminant semen preservation.     

The relationship between reduced glutathione level and glutathione S-transferase activity in sheep erythrocytes.

The relationship between reduced glutathione (GSH) level and glutathione S-transferase (GST) activity in erythrocytes was examined, using sheep erythrocytes, which have varying GSH concentrations, and dog erythrocytes with an inherited high concentration of GSH. There was a positive correlation (r = 0.529, p < 0.001) between the GSH level and GST activity in sheep erythrocytes. In dog erythrocytes, the GST activity in high-GSH cells was significantly (p < 0.001) higher than that in normal-GSH cells. These results indicate that the activity of GST in erythrocytes is directly correlated with the intracellular GSH level.     

Antioxidant effects of supplementation of 3,4-dihydroxyphenyl glycol on sperm parameters and oxidative markers following cryopreservation in canine semen

Supplementing the extender with antioxidants with low molecular weight can enhance the quality of the post-thaw sperm during the freezing process. This study was aimed at determining the impacts of 3,4-dihydroxyphenyl glycol (DHPG) on the spermatozoa of the canine undergoing freeze-thawing process. In this study, 24 ejaculates were obtained from three mixed-breed dogs and were diluted in a Tris-based extender. The diluted semen was divided into aliquots for supplementation of 10, 30, 50 and 70 µg/ml of DHPG, control (without antioxidant) and control sham (DMSO). After being extended, the semen was equilibrated at a temperature of 4°C and then transferred to the straws and kept 4 cm above the liquid nitrogen for 20 min and was finally immersed in the liquid nitrogen. They were cryopreserved for seven days; then, sperm parameters including sperm motility evaluation, motility characteristics, viability, DNA and plasma membrane integrity, total antioxidant capacity (TAC), reduced glutathione content (GSH), antioxidant enzymes (superoxide dismutase [SOD], catalase [CAT] and glutathione peroxidase [GPx]) activity malondialdehyde (MDA) levels were evaluated. This study showed that spermatozoa cryopreservation with 50, 30 and 70 µg/ml of DHPG concentrations had better progressive motility, Curvilinear Velocity, Linearity, viability, intact plasma membrane and the levels of TAC, GPx and GSH were higher than the control group. The 50, 30 and 70 µg/ml of DHPG concentrations led to the significant decrease of DNA damage compared to the control group. Total motility, average path velocity, straight-line velocity and CAT activity were significantly improved in 30 and 50 µg/ml of DHPG concentrations, compared to the control group. Also, the 50 and 30 µg/ml of DHPG concentrations, decreased MDA levels compared to the other groups, significantly. In conclusion, our study showed that the addition 50 µg/ml of DHPG to the canine semen extender improved the semen characteristics and oxidative markers in the cryopreservation process.     

Effects of ginsenosides on organogenesis and expression of glutathione peroxidase genes in cultured rat embryos

Ginseng has been extensively used around the world for several thousand years as a food or drug. However, recently, several reports have indicated that the organogenesis of cultured embryos is inhibited by treatment with ginsenoside, the principal component of ginseng. In this study, we evaluated the morphological changes of embryos and the gene expression patterns of antioxidant enzymes, 3 types of glutathione peroxidases [GPx; cytosolic (cGPx), plasma (pGPx) and phospholipid hydroperoxide (phGPx) forms], in cultured rat embryos (embryonic days 9.5-11.5) exposed to ginsenosides Rb1, Rg1, Re and Rc at levels of 5, 50 and 100 microg/ml. With regard to total morphological scores, no significant differences were noted in the embryos exposed to all doses of ginsenosides, with the exception of 50 microg/ml of Rc. In the cultured embryos exposed to Rg1, a majority of the developmental parameters were normal, but growth of the hind- and mid- brains and the caudal neural tube was significantly increased compared with that observed in the control group (P<0.05). Furthermore, Rc significantly enhanced the growth of a variety of developmental parameters in the cultured embryos, with the exception of the hindlimbs. According to the results of our semiquantitative RT-PCR analysis, the levels of cGPx and phGPx mRNA in the cultured embryos were unaffected by treatment with the ginsenosides. However, the levels of pGPx mRNA increased significantly in the embryos treated with ginsenosides Re, Rc and Rb1 compared with the control group (P<0.05). These findings indicate that ginsenosides may exert a stimulatory effect on the growth of embryos via differential expression of GPx genes.     

GSH对铅胁迫下多年生黑麦草幼苗抗氧化系统的调控

本试验以12周龄的多年生黑麦草（Lolium perenne ‘cuttle’）幼苗为试验材料,用铅（Lead,Pb）,Pb+还原型谷胱甘肽（Glutathione,GSH）和Pb+丁硫氨酸-亚砜亚胺（L-Buthionine-sulfoximine,BSO）处理1周,研究GSH对Pb胁迫下多年生黑麦草抗氧化系统的调控机理,寻求缓解植物Pb胁迫的有效措施。结果表明：Pb胁迫下,外源GSH能够显著提高多年生黑麦草Pb的吸收和转运,增加抗氧化酶超氧化物歧化酶（Superoxide dismutase,SOD）、谷胱甘肽过氧化物酶（Glutathione peroxidase,GPX）和谷胱甘肽还原酶（Glutathione reductase,GR）活性,显著增加抗氧化剂GSH含量及GSH/氧化型谷胱甘肽（Oxidized glutathione,GSSG）比率,提高了植物的还原力。外源GSH也能够显著降低活性氧超氧阴离子（Superoxide anion,O₂^·-）和过氧化氢（Hydrogen peroxide,H₂O₂）的产生量、膜的相对透性（Relative electric conductivity,EC）和丙二醛（Malondialdehyde,MDA）含量,保持了细胞的稳定性,减轻了膜脂的过氧化程度。外源BSO作用基本上与GSH相反。相关分析表明：GSH可通过提高SOD和GPX等抗氧化酶的活性,促进GSSG和GSH的相互转化,降低活性氧产生量,提高植物抵抗逆境胁迫的能力。     

Interrelationships of erythrocyte glutathione peroxidase system enzymes in the fasted Beagle

Eight adult female Beagles were fasted for 21 days to investigate responses of the erythrocyte glutathione peroxidase system enzymes. Blood samples were collected once a week. Erythrocyte reduced glutathione was maintained within 10% of base-line value. Hexose monophosphate pathway dehydrogenases showed a significant inverse relationship to glutathione reductase (GR) activity. Further, active GR, as a percentage of total GR, increased as hexose monophosphate pathway dehydrogenase activity fell. A similar relationship between these enzymes has been reported in human glucose-6-phosphate dehydrogenase deficiency. Also, glutathione peroxidase showed an inverse linear response to erythrocytic reduced glutathione. Though the responses of this system are complex, they appear interrelated.     

The effect of dietary Chlorella vulgaris inclusion on goat's milk chemical composition,fatty acids profile and enzymes activities related to oxidation

The impact of dietary supplementation with microalgae on goat's milk chemical composition, fatty acids (FA) profile and enzymes activities related to antioxidant mechanism has not been well documented. Thus, this study aimed to investigate the effects of dietary inclusion of Chlorella vulgaris on the following: (i) milk yield, chemical composition and FA profile, (ii) the activities of superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), glutathione transferase (GST) and glutathione peroxidase (GSH‐Px) in blood plasma and (iii) the activities of SOD, GR and lactoperoxidase (LPO) in milk of goats. Furthermore, the oxidative stress indicators for measuring total antioxidant and free radical scavenging activity [ferric reducing ability of plasma (FRAP) and 2, 2′‐azino‐bis (3‐ethylbenzothiazoline‐6‐sulphonic acid) (ABTS) assays] and oxidative stress biomarkers [malondialdehyde (MDA) and protein carbonyls (PC)] were also determined in blood plasma and milk of the animals. For this purpose, 16 cross‐bred goats were divided into two homogenous groups. Each goat of both groups was fed individually with alfalfa hay and concentrates separately. The concentrates of the control group (Control) had no microalgae, while those of the Chlorella group were supplemented with 10 g lyophilized Chlorella vulgaris/kg concentrates (Chlorella). Thus, the average intake was 5.15 g Chlorella vulgaris/kg DM. The results showed that the dietary inclusion of Chlorella vulgaris had not noticeable impact on goat's milk yield, chemical composition and FA profile. Significantly higher SOD (by 10.31%) and CAT (by 18.66%) activities in the blood plasma of goats fed with Chlorella vulgaris compared with the control were found. Moreover, the dietary supplementation with Chlorella vulgaris caused a significant increase in SOD (by 68.84%) activity and a reduction in PC (by 24.07%) content in goat's milk. In conclusion, the Chlorella vulgaris inclusion in goat's diets improved the antioxidant status of both animals and milk.     

Cellular injury and lipid peroxidation induced by hexavalent chromium in isolated rat hepatocytes

In order to elucidate the relationship between cellular injury and lipid peroxidation induced by hexavalent chromium (CrVI), isolated rat hepatocytes treated with any one of scavengers of active oxygen species, antioxidants or antichromium agent were incubated with K2Cr2O7 as CrVI (1 mM Cr). After the incubation, the development of lipid peroxidation was determined as thiobarbituric acid (TBA)-reacting materials in total lipid extracts from the incubated hepatocytes. Cellular injury was observed as a leakage of lactate dehydrogenase (LDH) from hepatocytes into incubation medium. The contents of reduced glutathione (GSH) in hepatocytes were also assessed. Results obtained were as follows: (1) CrVI facilitated lipid peroxidation in isolated hepatocytes after 20 min of incubation. On the other hand, the cellular injury induced by CrVI was barely observed even after 60 min of incubation. (2) The CrVI-induced lipid peroxidation was inhibited by catalase and mannitol as scavengers of active oxygen species, or N,N'-diphenyl-p-phenylenediamine and alpha-tocopherol as antioxidants. However the cytotoxicity of CrVI could not be prevented by these chemicals. (3) CrVI depleted the contents of intracellular GSH and diminished the activities of glutathione reductase (GR) and glutathione-S-transferase (GST) except glutathione peroxidase. (4) The scavengers of active oxygen species and the antioxidants could not prevent the depletion of intracellular GSH induced by CrVI. (6) Ascorbic acid, antichromium agent, prevented all of the lipid peroxidation, the cellular injury and intracellular GSH depletion induced by CrVI.(ABSTRACT TRUNCATED AT 250 WORDS)     

The oxidant defence system in water-buffaloes (Bubalus bubalis) experimentally infected with Anaplasma marginale

The glutathione (GSH) -oxidant defence system protects the erythrocytes and leucocytes from oxidative damage. Leucocyte -superoxide dismutase (SOD), GSH-peroxidase (GSH-px), GSH-reductase (GR), GSH-S-transferase (GSH-S-t) and arginase were examined in samples from buffaloes infected with Anaplasma marginale. All the enzymes, except arginase, were also studied in the red cell haemolysates from these animals. GSH-S-t, GSH- and glutathione-reductase (GR) levels in leucocytes decreased in infected animals suggesting a decline in the efficiency of the GSH-oxidant defence system. SOD levels increased but there was no change in leucocyte-arginase activity due to infection. Infection caused no significant changes in red cell SOD, GSH-px, GR and GSH. However, GSH-S-t significantly decreased (P less than 0.05).