Comparative study of antioxidant enzymes in tissues surrounding implant in rabbits

There is a possible role of reactive oxygen species (SROS) in the complication of implants although there is presently little information. The aim of this study was to investigate the alterations in lipid peroxidation (LP) and antioxidant enzyme activities in tissues surrounding implants in rabbits. Thirty New Zealand albino male rabbits were used. They were randomly divided into five groups. The first group (I) was used as control. Groups II, III, IV and V were implanted with stainless steel, ceramic, titanium and polyethylene, respectively. One month after the administration of implant, the tissues surrounding the implant were carefully removed for antioxidant enzyme analysis. Glucose-6-phosphate dehydrogenase (G6PD), glutathione reductase (GR), superoxide dismutases (SOD), glutathione peroxidase (GPx), catalase (CAT) in tissues surrounding the implants in the groups II, III and IV were significantly (p<0.05-p<0.001) lower than in the control group although glutathione S-transferase (GST) activities and LP values were increased. CAT activity and LP level did not decrease in group V. In conclusion, these data demonstrate that there is an increase in lipid peroxidation in the tissues surrounding ceramic and titanium implants of animals whereas there is a decrease in antioxidant enzymes. Oxidative stress plays a very important role in the complications of ceramic and titanium implants. The polyethylene implant seems to be the best of the four implant materials tested.     

Dietary Mannan-oligosaccharides potentiate the beneficial effects of Bifidobacterium bifidum in broiler chicken

This study investigated the effects of dietary Bifidobacterium bifidum (BFD) and mannan-oligosaccharide (MOS), as a synbiotic, on the production performance, gut microbiology, serum biochemistry, antioxidant profile and health indices of broiler chicken. Six dietary treatments were T1 (negative control), T2 (positive control-20 mg antibiotic BMD kg⁻¹ diet; BMD: bacitracin methylene disalicylate), T3 (0·1% MOS + 10⁶ CFU BFD per g feed), T4 (0·1% MOS + 10⁷ CFU BFD per g feed), T5 (0·2% MOS + 10⁶ CFU BFD per g feed) and T6 (0·2% MOS + 10⁷ CFU BFD per g feed). Significantly (P < 0·01) better growth performance and efficiency was observed in birds supplemented with 0·2% MOS along with 10⁶ CFU BFD per g of feed compared to BMD and control birds. Supplementation with 0·2% MOS along with either 10⁶ or 10⁷ CFU BFD per g feed reduced (P < 0·01) the gut coliform, Escherichia coli, total plate count, and Clostridium perfringens count and increased the Lactobacillus and Bifidobacterium count. Significantly (P < 0·01) higher serum and liver antioxidant enzyme pool, serum HDL cholesterol and lower serum glucose, triglyceride, total cholesterol, cardiac risk ratio, atherogenic coefficient and atherogenic index of plasma were observed in birds supplemented with 0·2% MOS along with 10⁶ CFU BFD per g of feed compared to control or BMD supplemented birds. Better production performance, gut microbial composition, serum biochemistry, antioxidant profile and health indices were depicted by broiler chicken supplemented with 0·2% MOS and 10⁶ CFU BFD per g of feed.     

Selenium-induced changes in activities of antioxidant enzymes and content of photosynthetic pigments in Spirulina platensis

Spirulina platensis exposed to various selenium （Se） concentrations （0, 10, 20, 40, 80, 150, 175, 200, 250 mg/L） accumulated high amounts of Se in a dose- and time-dependent manner. Under low Se concentrations （〈150 mg/L）, Se induced increases in biomass concentration, content of photosynthetic pigments, and activities of glutathione peroxidase （GPX）, superoxide dismutase （SOD）, catalase （CAT） and Gua-dep peroxidases （POD）, which indicates that antioxidant enzymes play an important role in protecting cells from Se stress. Higher Se concentrations （≥175 mg/L） led to higher Se accumulation and increases in activities of GPX, SOD, CAT and POD, but also induced lipid peroxidation （LPO） coupled with potassium leakage and decreases in biomass concentration and contents of photosynthetic pigment. The results indicate that increases in activities of the antioxidant enzymes were not sufficient to protect cell membranes against Se stress. Time-dependent variations in the activities of antioxidant enzymes, contents of chlorophyll a and carotenoid and the LPO level were also investigated under representative Se concentrations of 40 and 200mg/L. Opposite variation trends between SOD-CAT activities, and GPX-POD-APX activities were observed during the growth cycles. The results showed that the prevention of damage to cell membranes of S. platensis cells could be achieved by cooperative effects of SOD-CAT and GPX-POD-APX enzymes. This study concludes that S. platensis possessed tolerance to Se and could protect itself from phytotoxicity induced by Se by altering various metabolic processes.     

Detoxification enzymes of freshwater crayfish Procambarus clarkii fed a diet enriched in selenium: Preliminary results

This study aimed at investigating the extent of accumulation of selenium in the hepatopancreas of the crayfish Procambarus clarkii and its effects on the enzymatic activities of catalase, glutathione peroxidase, and glutathione reductase. Crayfish were fed for 15 days either a diet enriched in Se, ED (1.21 mg kg^-1) or a standard diet, SD (0.30 mg kg^-1). Results showed that Se accumulation is higher in the sample subject to ED rather than to SD. A sexual difference was found for the response of the analyzed enzymes in the ED sample only. Catalase activity and glutathione peroxidase activity decreased in females and males, respectively, whereas glutathione reductase activity showed significant reductions in both sexes. These preliminary data might provide information about prooxidant effects of Se on P. clarkii when fed a Se enriched diet.     

Beneficial effects of enrichment of chicken meat with n-3 polyunsaturated fatty acids,vitamin E and selenium on health parameters: a study on male rats

Consumption of chicken meat enriched with bioactive compounds such as n-3 polyunsaturated fatty acids (PUFAn-3), vitamin E (vE) and selenium (Se) can help prevent many diseases and can be used to deliver those substances to humans. This might be of importance as chicken meat consumption is increasing worldwide. The effects of enriching chicken meat with PUFAn-3, vE and Se through dietary interventions were studied in rats. Four groups of Ross 308 female broilers from day 22 to day 35 of age were fed control diet (L) that contained lard and 80 mg vE and 0.3 mg Se/kg, or diets that contained rape seeds and fish oil with the same level of Se and vE as in the control diet, the same level of Se as in the control and 150 mg vE/kg, or 150 mg of vE and 0.7 mg Se/kg. Broiler carcasses were boiled, deboned, lyophilized and pooled by group. Boiled edible components of chicken carcass (BECC) were included (240 g/kg) in the diets fed to four groups of ten 10-week-old Wistar male rats for 8 weeks. Inclusion of BECCs modulated dietary fatty acid profile in the rat diets. Feeding these diets did not influence parameters related to growth or relative weights of internal organs in the rats. Feeding BECCs with lower PUFAn-6/n-3 decreased the n-6/n-3 ratio in the rat brain and liver, and increased the proportion of docosahexaenoic acid in the brain lipids. Liver cholesterol level was similar among the experimental groups, whereas the concentration of vE in the liver of rats fed BECC with increased vE levels was higher than that in the rats fed BECC with the basal vE level. Haematological and biochemical parameters in blood were within the normal range for rats, but a few rats showed a tendency towards increased levels because of the higher vE and Se level. The health-promoting effect of feeding rats PUFAn-3 enriched BECC was more pronounced when an increased dietary level of vE was used, but the increased level of Se did not provide the rats with additional benefits. Thus, the findings indicate that BECC enriched with PUFAn-3 and vE by a dietary intervention is a functional food with great potential of implementation.     

Protective effects of the antioxidant selenium on quinolinic acid-induced neurotoxicity in rats: in vitro and in vivo studies

Quinolinic acid (QUIN), a well known excitotoxin that produces a pharmacological model of Huntington's disease in rats and primates, has been shown to evoke degenerative events in nerve tissue via NMDA receptor (NMDAr) overactivation and oxidative stress. In this study, the antioxidant selenium (as sodium selenite) was tested against different markers of QUIN-induced neurotoxicity under both in vitro and in vivo conditions. In the in vitro experiments, a concentration-dependent effect of selenium was evaluated on the regional peroxidative action of QUIN as an index of oxidative toxicity in rat brain synaptosomes. In the in vivo experiments, selenium (0.625 mg per kg per day, i.p.) was administered to rats for 5 days, and 2 h later animals received a single unilateral striatal injection of QUIN (240 nmol/ micro L). Rats were killed 2 h after the induction of lesions with QUIN to measure lipid peroxidation and glutathione peroxidase (GPx) activity in striatal tissue. In other groups, the rotation behavior, GABA content, morphologic alterations, and the corresponding ratio of neuronal damage were all evaluated as additional markers of QUIN-induced striatal toxicity 7 days after the intrastriatal injection of QUIN. Selenium decreased the peroxidative action of QUIN in synaptosomes both from whole rat brain and from the striatum and hippocampus, but not in the cortex. A protective concentration-dependent effect of selenium was observed in QUIN-exposed synaptosomes from whole brain and hippocampus. Selenium pre-treatment decreased the in vivo lipid peroxidation and increased the GPx activity in QUIN-treated rats. Selenium also significantly attenuated the QUIN-induced circling behavior, the striatal GABA depletion, the ratio of neuronal damage, and partially prevented the morphologic alterations in rats. These data suggest that major features of QUIN-induced neurotoxicity are partially mediated by free radical formation and oxidative stress, and that selenium partially protects against QUIN toxicity.     

鸡Foxp3结构预测及组织表达谱分析

本研究旨在克隆鸡foxp3 (chfoxp3)基因全长编码区序列(coding sequence,CDS),并对其进行生物信息学及组织表达谱分析。以50日龄无特定病原鸡为样本,从脾脏组织中克隆chfoxp3基因全长CDS序列,利用在线工具和软件对chFoxp3进行生物信息学分析,以实时荧光定量PCR (quantitative real-time PCR,qRT-PCR)技术检测chfoxp3基因在鸡各组织中的表达分布情况。研究结果表明,chfoxp3基因包含882 bp的开放阅读框,编码293个氨基酸,chFoxp3分子质量为33.44 kDa,属于亲水蛋白;chFoxp3具有Fox转录因子家族典型的forkhead结构域,含有核定位信号;其二级结构由α-螺旋(29.35%)、延伸链(10.92%)、β-转角(5.12%)和无规则卷曲(54.61%)组成;chfoxp3在不同组织中表达有差异,在鸡心脏及胰腺中表达水平较高,显著高于脾脏、法氏囊以及胸腺等免疫器官(P<0.01),这一特点明显区别于哺乳动物;通过系统进化树分析发现,鸡Foxp3与其他野禽属于相同分支,但与哺乳动物相差较远。这些研究结果为进一步深入研究chFoxp3的免疫调节功能奠定了基础。     

A comparative study on effect of dietary selenium and vitamin E on some antioxidant enzyme activities of liver and brain tissues

Since selenium and vitamin E have been increasingly recognized as an essential element in biology and medicine, current research activities in the field of human medicine and nutrition are devoted to the possibilities of using these antioxidants for the prevention or treatment of many diseases. The present study was aimed at investigating and comparing the effects of dietary antioxidants on glutathione reductase and glutathione peroxidase activities as well as free and protein-bound sulfhydryl contents of rat liver and brain tissues. For 12–14 wk, both sex of weanling rats were fed a standardized selenium-deficient and vitamin E-deficient diet, a selenium-excess diet, or a control diet. It is observed that glutathione reductase and glutathione peroxidase activities of both tissues of the rats fed with a selenium-deficient or excess diet were significantly lower than the values of the control group. It is also shown that free and bound sulfhydryl concentrations of these tissues of both experimental groups were significantly lower than the control group. The percentage of glutathione reductase and glutathione peroxidase activities of the deficient group with respect to the control were 50% and 47% in liver and 66% and 61% in the brain, respectively; while these values in excess group were 51% and 69% in liver and 55% and 80% in brain, respectively. Free sulfhydryl contents of the tissues in both experimental groups showed a parallel decrease. Furthermore, the decrease in protein-bound sulfhydryl values of brain tissues were more pronounced than the values found for liver. It seems that not only liver but also the brain is an important target organ to the alteration in antioxidant system through either a deficiency of both selenium and vitamin E or an excess of selenium alone in the diet.     

Selenium and sulfur accumulation and soil selenium dissipation in planting of four herbaceous plant species in soil contaminated with drainage sediment rich in both selenium and sulfur

Four selenium (Se) nonaccumulator plant species, including a forage grass species, Tall Fescue (Festuca arundinacea Schreb.), a forage legume species, Alfalfa (Medicago sativa L.), a wetland species, Rush (Juncus tenuis Wild.), and a dry-land alkaline soil species, Saltgrass (Distichlis spicata L.), were grown in soil contaminated by agricultural drainage sediment having elevated levels of Se and sulfur (S). The above-ground plant tissues were consecutively harvested five times and examined for Se and S accumulation. Plant tissue Se concentrations ranged from 23.0 mg kg-1 to 8.3 mg kg-1. Tissue S concentrations ranged from 3239 mg kg-1 to 7034 mg kg-1. Both tissue Se and S concentrations were significantly different between harvests, species, and species/harvest interactions. Total Se accumulation by the plant biomass harvested ranged from 0.3 to 1.3 mg per soil column and total S accumulations ranged from 87.5 to 321.1 mg per soil column. The reduction in the percentage of total soil Se after 24 weeks growth of the plant species ranged from 12.0% in the Tall Fescue planting to 17.3% in the Rush planting. Over 90% of the soil Se losses were unidentified losses and leaching of Se was prevented. The accumulations of Se and S in the plant biomass were very small compared with the total soil Se and S losses, but substantial amounts of total soil Se (12.0 to 15.0%) and S (28.0 to 50.9%) inventories were dissipated by the growing and harvesting of the plants. The soil S concentration was several hundred times higher than the soil Se concentration, but Se accumulation by the plants and Se dissipation from the soil were not impaired by the high level of soil sulfur. For natural grassland habitat restoration, such as at the Kesterson Wildlife Refuge in the Central Valley of California, or for restoration of large-scale Se contaminated agricultural lands, Se nonaccumulator plant species are favorable candidates, because the possibility of introducing Se toxicity into the food chain can be minimized.     

Modulations in antioxidant enzymes in different tissues of marine bivalvePerna viridis during heavy metal exposure

Lipid peroxidation induced by metals at sub-lethal levels, alter physiological and biochemical characteristics of biological systems. To counter the detrimental effects of the prooxidant activity of metals, a group of antioxidant enzyme systems function in the organisms. The present study was performed to investigate into the lipid peroxidation product formation due to the exposure to effects of the metals namely aluminium, lead and cadmium at sub-lethal concentrations and the biological response through protective antioxidant enzyme activity in the marine mussels,Perna viridis Lin. This organism is a known bioindicator and bioconcentrator of metals in the environment.The results of the present study were: (a) accumulation of lead showed a definite linear increase during the period of exposure whereas aluminium and cadmium showed fluctuations. Mantle and gill tissues showed greater accumulation of metals when compared to digestive gland; (b) lead and aluminium induced lipid peroxidation was greater in tissues than the peroxidation induced by cadmium. Cadmium induced peroxidation was observed only after the day 7 of the exposure; (c) anti-oxidant enzymes activity levels were significantly higher in digestive gland and mantle than gills; (d) mantle was observed to significantly contribute to the organismal response to lipid peroxidation as indicated by high activity levels of anti-oxidant enzymes.     

维生素E和硒水平对肉鸡不同自由基代谢的影响

选用200羽14日龄健康AA肉鸡,以电子自旋共振(ESR)捕集法和生物化学法对肉仔鸡血液和组织器官的不同自由基进行直接或间接测定,探讨VE和Se对肉鸡不同自由基代谢的作用及其动态变化.结果表明:组织一氧化氮(NO)自由基水平随日粮VE含量升高而降低,二者呈负相关关系,日粮高水平Se有诱导产生NO自由基的倾向;高VE和Se日粮显著提高血清和肝脏中SOD和GSH-Px的活性,但随处理时间的延长,组织SOD活性逐渐降低,而GSH-Px活性逐渐升高,说明日粮VE和/或Se不足均会诱导机体产生O.2-、H2O2自由基,且O2.-自由基会持续大量产生,而H2O2自由基仅在缺乏初期大量产生,而后趋于缓和;低VE和/或低Se均显著提高组织MDA含量,且低Se比低VE更为显著.VE和Se对肉鸡NO、O.2-和H2O2自由基代谢的作用存在协同效应.     

Clostridium perfringens challenge and dietary fat type affect broiler chicken performance and fermentation in the gastrointestinal tract

The aim of the present work was to examine how different fats commonly used in the feed industry affect broiler performance, nutrient digestibility and microbial fermentation in the gastrointestinal tract of broiler chickens challenged with virulent Clostridium perfringens strains. Two experiments were carried out, each including 480-day-old male broilers (Ross 308), which were randomly distributed to eight experimental groups using six replicate pens per treatment and 10 birds per pen. In Experiment 1, birds were fed diets containing soybean oil, palm kernel fatty acid distillers, rendered pork fat and lard. In Experiment 2, birds were fed diets containing rapeseed oil, coconut oil, beef tallow and palm oil. In both experiments, the birds were either not challenged or challenged with a mixture of three C. perfringens type A strains. Irrespective of the fat type present in the diet, C. perfringens did not affect broiler chicken body weight gain (BWG) and mortality in either of the two experiments. The BWG was affected by dietary fat type in both experiments, indicating that the fatty acid composition of the fat source affects broiler growth performance. In particular, the inclusion of animal fats tended to improve final BW to a greater extent compared with the inclusion of unsaturated vegetable oils. In Experiment 2, irrespective of the dietary fat type present in the diet, C. perfringens challenge significantly impaired feed conversion ratio in the period from 14 to 28 days (1.63 v. 1.69) and at 42 days (1.65 v. 1.68). In both experiments apparent metabolizable energy values were affected by dietary fat type. Irrespective of the fat type present in the diet, C. perfringens challenge decreased the digesta pH in the crop and ileum, but had no effect in cecal contents. Moreover, in Experiment 1, total organic acid concentration in the ileum was two to three times lower on soybean oil diets as compared with other treatments, indicating that C. perfringens as well as dietary fat type significantly affects microbiota activity in the broiler chicken gastrointestinal tract.     

microRNA-33-3p involved in selenium deficiency-induced apoptosis via targeting ADAM10 in the chicken kidney

Selenium (Se) deficiency induces typical clinical and pathological changes and causes various pathological responses at the molecular level in several different chicken organs; the kidney is one of the target organs of Se deficiency. To explore the mechanisms that underlie the effects of microRNA-33-3p (miR-33-3p) on Se deficiency-induced kidney apoptosis, 60 chickens were randomly divided into two groups (30 chickens per group). We found that Se deficiency increased the expression of miR-33-3p in the chicken kidney. A disintegrin and metalloprotease domain 10 (ADAM10) was verified to be a target of miR-33-3p in the chicken kidney. The overexpression of miR-33-3p decreased the expression levels of β-catenin, cyclinD1, T-cell factor (TCF), c-myc, survivin, and Bcl-2; it increased the expression levels of E-cadherin, Bak, Bax, and caspase-3; and it increased the number of chicken kidney cells in the G0/G1 phase. In addition, Se deficiency caused the ultrastructure of the kidney to develop apoptotic characteristics. The results of flow cytometry analysis and AO/EB staining showed that the number of apoptotic chicken kidney cells increased in the miR-33-3p mimic group. All these results suggest that Se deficiency-induced cell cycle arrest and apoptosis in vivo and in vitro in the chicken kidney via the regulation of miR-33-3p, which targets ADAM10.     

Differential expression of antioxidant enzymes in various hepatocellular carcinoma cell lines

Recent evidence suggests that reactive oxygen species (ROS) play an important role in the pathogenesis of various illnesses, and the ROS and antioxidant enzymes are highly associated with cell differentiation and diseases. In this study, we tested the hypothesis that specific antioxidant enzymes are differentially expressed in hepatocellular carcinoma (HCC) cell lines with various degrees of differentiation. We compared the expression of several antioxidant enzymes including catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GRx), and glutathione peroxidase (GPx) in five HCC cell lines with well (Hep G2 and Hep 3B) or poor (HA22T/VGH, HA55T/VGH, and SK-Hep-1) differentiation. Our results showed that both well-differentiated HCC cell lines expressed extremely higher CAT and GRx enzyme activities than all three poorly differentiated ones. Moreover, the protein and mRNA levels of CAT were much higher in two well-differentiated HCC cell lines than in all three poorly differentiated ones. Both well-differentiated HCC cell lines also showed a higher protein or mRNA expression of Cu/ZnSOD and MnSOD than three poorly differentiated ones. Our results demonstrate that specific antioxidant enzymes (especially, CAT and GRx) are differentially expressed in HCC cell lines with well or poor differentiation. These findings suggest that CAT and GRx are two potential differentiation markers for HCC.     

Colostrum and milk selenium,antioxidative capacity and immune status of dairy cows fed sodium selenite or selenium yeast

Dietary selenium (Se) can be supplemented from organic or inorganic sources and this may affect Se metabolism and functional outcome such as antioxidative status and immune functions in dairy cows. A feeding trial was performed with 16 Holstein-Friesian dairy cows fed with a total mixed ration (0.18 mg Se/kg dry matter (DM)) either without Se supplement (Control, n = 5), or with Se from sodium selenite (Group SeS, n = 5) or Se yeast (Group SeY, n = 6). In Groups SeS and SeY, the Se supplementation amounted to an additional intake of 4 mg Se and 6 mg Se/d during gestation and lactation, respectively. The effect of both Se sources was characterised by milk Se and antioxidant levels, and the phenotyping and functional assessment of phagocytic activity of milk immune cells. Se yeast has been found to increase (p ≤ 0.001) the milk Se and antioxidant levels markedly compared to the control group. The experimental treatment did not affect the immune parameters of the cows. Lymphocyte subpopulations and phagocytosis activity of neutrophilic granulocytes were affected neither by the Se intake nor by the two different dietary supplements. It can be concluded that sodium selenite and Se yeast differ considerably in their effects on antioxidant status in dairy cows. However, the basal dietary Se concentration of 0.18 mg/kg DM seemed to be high enough for the measured immune variables.     

Seasonal fluctuations of selenium and sulfur accumulation in selenium hyperaccumulators and related nonaccumulators

Some plants hyperaccumulate selenium (Se) up to 1% of dry weight. This study was performed to obtain insight into whole-plant Se fluxes in hyperaccumulators. Selenium hyperaccumulators Astragalus bisulcatus and Stanleya pinnata were monitored over two growing seasons for seasonal fluctuations in concentrations of Se and the chemically similar element sulfur (S). The related nonhyperaccumulators Astragalus sericoleucus, Oxytropis sericea and Thlaspi montanum were included for comparison. In both hyperaccumulators leaf Se decreased from April to October, coinciding with Se hyperaccumulation in flowers and seeds. Root Se levels were lowest in summer. Selenium concentration decreased with leaf age in both hyperaccumulators. Leaf S levels peaked in summer in all plant species, as did Se levels in nonhyperaccumulators. Selenium and S levels tended to be negatively correlated in hyperaccumulators, and positively correlated in nonhyperaccumulators. These results suggest a specific flow of Se in hyperaccumulator plants over the growing season, from root to young leaves in spring, followed by remobilization from aging leaves to reproductive tissues in summer, and back to roots in the autumn.     

灵芝富硒研究进展

对灵芝的富硒和耐硒特性,硒对灵芝生长代谢的影响,富硒灵芝中硒的赋存形态和含量分布以及富硒灵芝药理活性等方面的研究进展作了概述,并对灵芝富硒研究的发展趋势和前景进行了探讨。     

Toxic levels of selenium in enzymes and selenium uptake in tissues of a marine fish

Acute toxicity of selenium as selenite inZosterisessor ophiocephalus by ip injection was studied. The 50% lethal dose and 50% lethal time were measured to be 0.29 ppm and 96 h, respectively. Se concentrations in liver, gill, skin and muscle, and Cyt. P450 level, Se-GPx, and Total GPx enzyme activities in liver were also assessed at different doses and times after injection. Starting at 0.3 ppm injected dose, enzyme activities and Se concentration in tissues but not in muscle, showed significant differences from the control group. A threshold behavior was inferred. Normal conditions of enzyme activities and Se concentration in tissues were restored about 1 wk after injection. Biological elimination half-lives were about 2 d for liver and gill, and 5 d for skin.