离子色谱法测定有机化合物中的硒

用多孔聚乙烯醇季铵基化学键离子交换柱的离子色谱法 ,观察含亚硒酸及硒酸的 9种阴离子的洗脱踪迹 ,确立分离条件 ,并利用有机硒化合物的燃烧生成物亚硒酸或者硒酸 ,通过离子色谱测定有机硒化合物中的硒。亚硒酸标准溶液 :取一定量的亚硒酸钠( Na2 Se O3 · 5H2 O,纯度 99%以上 )配制成每毫升 1 mg,临用时稀释。硒酸标准溶液 :取一定量的硒酸钠 ( Na2 Se O4 ,纯度 97%以上 )配制成每毫升 1 mg,临用前稀释。碳酸钠及碳酸氢钠标准溶液 :分别称取优级纯的碳酸钠及碳酸氢钠 ,配制成 0 .2 mol/L,临用时稀释。离子对试剂 :Dionex产品 ,0 .1 mo…     

硒对大鼠肝脏超氧阴离子和羟自由基的作用

目的 研究离体和在体染毒条件下亚硒酸钠对大鼠肝组织超氧阴离子(^*O2^-)和羟自由基(^*OH)生成的影响。方法 选用雄性Wistar大鼠。体外实验时，制备肝匀浆，在反应体系中加入亚硒酸钠使剂量分别达到2．185，8．750和35．000μmol／L。采用常规方法测定^*O2^-和^*OH。体内实验时，用0．75，1．50和3．00mg／kg的亚硒酸钠，腹腔注射染毒。采用电子自旋共振测定^*O2^ 和^*OH。结果 在体外染毒时，2．185μmol／L的亚硒酸钠对大鼠肝组织产生抗氧化应激作用，使过氧化脂质(MDA)、^*O2^ 和^*OH的生成量明显下降，但8．750和35．000μmol／L的亚硒酸钠则诱导大鼠肝组织产生明显的氧化应激，使^*O2^ 和^*OH的生成量显著升高。在体内染毒时，0．75，1．50和3．00mg／kg的亚硒酸钠均可引起大鼠肝组织^*O2^-和^*OH的产生量显著增加。结论 适宜剂量的亚硒酸钠抑制自由基生成。具有抗氧化作用，而较高剂量的亚硒酸钠则使自由基生成增多，导致明显的氧化应激。     

补充不同水平亚硒酸钠和硒蛋氨酸对大鼠硒代谢的影响

目的　研究各组织在硒代谢中的作用。方法　将断乳Wistar大鼠随机分为成 9组 ,每组 14只 ,雌雄各半。其中一组为对照组 ,另外 8组给予亚硒酸钠或硒蛋氨酸分别为Se 3、6、10、15mg kg饲料 ,饲养 12周。取组织进行硒测定。结果　补充亚硒酸钠组大鼠硒主要分布于肝脏、肾脏、红细胞和骨等组织 ,而补充硒蛋氨酸组大鼠体内硒主要分布在肌肉 ,其次为肝脏、肾脏、骨和红细胞等组织中。结论　硒蛋氨酸组比亚硒酸钠组大鼠更易发生硒蓄积。雌雄大鼠组织器官中的硒含量有差异。骨、毛和红细胞等组织的硒含量和饲料硒水平具有较好的相关性。     

我国14个城市饮用水中硒形态水平分布研究

目的了解我国重点流域和湖泊14个城市饮用水中5种常见硒形态水平和分布特征,为硒的污染防控和限值修订提供依据。方法在9个重点流域和1个重点湖泊(巢湖)选择14个城市的28个市政水厂作为监测点,于2020年11—12月分别采集水源水、出厂水和末梢水共84份水样。采用高效液相色谱—电感耦合等离子体质谱联用法(HPLC-ICP-MS)测定水样中5种不同硒形态[3种有机硒:硒代胱氨酸(SeCys2)、甲基硒代半胱氨酸(MeSeCys)、硒代蛋氨酸(SeMet);2种无机硒:亚硒酸根Se(Ⅳ)、硒酸根Se(Ⅵ)]浓度水平。采用Kruskal-Wallis H检验和Mann-Whitney U检验分析不同水样类型和不同水源类型中硒形态浓度水平的差异。结果我国14个城市饮用水中3种有机硒形态均未检出,Se(Ⅳ)、Se(Ⅵ)、总无机硒和5种形态硒总量的中位数(最小值,最大值)分别为0.03(0.03,0.39)、0.18(0.03,0.58)、0.23(0.06,0.79)和0.45(0.29,1.01)μg/L。水源水中Se(Ⅳ)浓度水平高于出厂水和末梢水(P<0.05),水源水、出厂水和末梢水中Se(Ⅵ)、总无机硒和5种形态硒总量浓度水平差异均无统计学意义(H为0.86~3.12,P>0.05)。地表水中Se(Ⅳ)、Se(Ⅵ)、总无机硒和5种形态硒总量浓度水平均高于地下水(Z分别为-2.72、-2.98、-3.50和-3.50,P<0.05)。结论本次研究饮用水中3种有机硒形态未检出、水中硒主要以无机硒Se(Ⅳ)和Se(Ⅵ)形态存在。不同水样类型和不同水源类型水样中Se(Ⅳ)和Se(Ⅵ)有不同程度检出,但浓度水平均未超标。总无机硒水平不会对人体产生健康风险,但仍需加强饮用水中硒形态水平监测,同时人群可从膳食角度补充有机硒的摄入。     

亚硒酸钠和硒蛋氨酸的毒性比较

目的　比较亚硒酸钠和硒蛋氨酸毒性差异以及探讨硒中毒的指标。方法　将断乳Wistar大鼠随机分为 7组 ,每组 14只 ,雌雄各半。其中一组为对照组 ,另外六组分别给予含硒 3、6、10mg kg的亚硒酸钠或硒蛋氨酸饲料 ,于第 12周将其处死。结果　当饲料硒水平达到 3mg kg时 ,动物肝脏出现病理变化 ,在Se6mg kg时 ,体重才出现下降。饲料硒水平为 6、10mg kg时 ,同一饲料硒水平的亚硒酸钠组大鼠体重小于硒蛋氨酸组。饲料硒水平为 3、6mg kg时 ,硒蛋氨酸组大鼠的肝脏病理改变轻于亚硒酸钠组 ,雄性大鼠轻于雌性。亚硒酸钠组较硒蛋氨酸组或雌性大鼠较雄性大鼠在肝脏体重比方面变化更为明显。除雌性大鼠肝脏谷胱甘肽过氧化物酶 (GPX)活性随硒水平升高而降低外 ,其它补硒各组肝、红细胞、血浆GPX活性具有随硒水平的升高而升高的趋势。结论　大鼠硒中毒的剂量为Se 3mg kg,硒蛋氨酸的毒性小于亚硒酸钠 ,雌性大鼠对硒毒性更为敏感     

富硒益生菌对小鼠免疫功能及抗氧化能力的影响

目的:研究富硒益生菌对小鼠免疫功能和抗氧化能力的影响。方法:100只昆明系小鼠,雌雄各半,随机均分为5组:对照组、亚硒酸钠组、富硒酵母组、富硒益生菌组和益生菌组,每天分别灌胃(ig)蒸馏水、亚硒酸钠(2μgSe/ml)、富硒酵母(2μgSe/ml)、富硒益生菌(2μgSe/ml)、益生菌各1ml,连续28d。实验结束时测定有关免疫功能和抗氧化能力指标。结果:胸腺指数与腹腔巨噬细胞活性,富硒益生菌组显著高于其它4组;脾脏指数,富硒益生菌组显著高于对照组、亚硒酸钠组和益生菌组;脾脏淋巴细胞转化率,富硒益生菌组显著高于对照组和益生菌组;GSH-Px与SOD活性,富硒益生菌组极显著或显著高于对照组和亚硒酸钠组;MDA水平,富硒益生菌组非常显著低于对照组和亚硒酸钠组。结论:富硒益生菌能明显改善小鼠免疫功能和抗氧化能力,其改善小鼠免疫功能的效果优于富硒酵母、亚硒酸钠和益生菌,提高小鼠抗氧化能力的效果优于亚硒酸钠。     

褪黑素对低硒饮食大鼠脂质过氧化的影响

目的 :研究褪黑素对低硒粮喂养的大鼠脂质过氧化增强的影响 ,并讨论其可能机制。方法 :将SD大鼠分为 3组 ,分别用低硒饲料、低硒饲料加硒、低硒饲料加褪黑素灌胃饲养 ,12周时检测血Se、血GSH—Px及心肌组织、肝组织匀浆MDA水平。结果 :12周时低硒组大鼠血Se、GSH—Px较加硒组 (对照组 )显著降低 ,心肌组织、肝组织匀浆MDA均明显高于其它两组。加硒组与褪黑素组MDA无显著差异。结论 :褪黑素可以显著抑制低硒饮食大鼠脂质过氧化的增强 ,作用与其抗氧化机制有关     

硒卡拉胶临床应用现状

硒卡拉胶胶囊是继亚硒酸钠后的一种新型有机硒化合物,其有效成份是微量元素硒与卡拉胶合成的,它不仅降低了无机硒的毒副作用,并大大提高了硒的生物利用度,与无机硒相比更有利于机体吸收,本文对其临床应用现状作一探讨。     

补硒对克山病病区粮饲养大鼠心肌线粒体单胺氧化酶活性的影响

90只断乳两周的Spragul-Dawley纯种大鼠,随机分为低硒、补硒及常备饲料三组,分别饲以克山病病区低硒粮(含Se 0.009ppm)、克山病病区低硒粮补亚硒酸钠(含Se 0.232ppm)及常备饲料(含Se 0.169ppm),观察硒对心肌线粒体单胺氧化酶活性(MAO)的影响,结果表明:与补硒和常备饲料组相比,低硒组心肌线粒体MAO活性明显下降。饲喂30,60,90天血浆硒含量和红细胞GSH-Px活性显著下降,补硒组心肌线粒体MAO和红细胞GSH-Px活性接近常备饲料组水平。     

硒对高血糖SD大鼠作用及作用机制的研究

用四氧嘧啶致高血糖 SD大鼠模型 ,研究无机硒对高血糖大鼠的作用 ,并对其作用机制进行初步探讨。结果表明 :以 1 5μg/kg亚硒酸钠连续腹腔注射 7天 ,1周后能有效升高高血糖大鼠谷胱甘肽过氧化物酶 (GSH- Px)活性及肝糖元的含量 ,显著降低丙二醛 (MDA)的含量和乳酸脱氢酶 (LDH)活性 ,而有微降血糖作用 ,但对乳酸含量无明显变化。结论 :无机硒可以增强四氧嘧啶高血糖大鼠抗氧化能力、降低脂质过氧化 ,在一定程度上缓解和清除自由基。     

大鼠对富硒平菇硒的生物利用率

本实验用低硒大鼠对人工栽培富硒平菇作了硒生物利用率观察。大鼠按体重随机分为9组,其中1组为低硒对照组,2～5组补充Na_2SeO_3,饲料内硒含量分别为:0.51、0.75、1.91、3.18ppm;6～9组补充富硒平菇,硒为0.45、0.72、1.59、3.41ppm。3周后处死大鼠,采血、肝、测定硒含量,并测定红细胞GSH-Px酶活性。结果表明:血、肝硒值及红细胞GSH-Px酶活性均随补硒浓度的增加而增加,以亚硒酸钠为基准,富硒平菇硒生物利用率,按血硒指标为66.66％;按肝硒指标为125％;按红细胞GSH-Px酶活性指标为123.42％,说明人工栽培富硒平菇可作为极好的食物硒来源。     

4种富硒植物预防MNNG诱发大鼠胃癌效果研究 二、不同源硒预防大鼠胃癌的安全性对比研究

目的对比研究长期摄入高剂量不同源硒的安全性。方法以亚硒酸钠为对照硒材料,采用N-甲基-N′-硝基-N-亚硝基胍(MNNG)诱发大鼠胃癌模型,连续灌以4种不同富硒植物(高剂量硒)17周,测定肝脏谷胱甘肽硫转移酶(GST)、血清谷草转氨酶(AST)和血清谷丙转氨酶(ALT)活性,并观察肝脏和肾脏的病理变化。结果各组大鼠肝GST活性均无显著性差异;75μg/kg bw(以Se计,下同)亚硒酸钠低剂量组大鼠血清AST和ALT活性不仅显著高于空白对照和MNNG组,而且显著高于150μg/kg bw和300μg/kg bw植物硒处理组(P<0.05)。病理分析发现75μg/kg bw亚硒酸钠低剂量组胆管周围有棕黄色颗粒,窦内枯否氏细胞轻度肥大、增生;其余各组未发现有意义的病变。结论亚硒酸钠毒性至少是实验用其它富硒植物的4倍。     

Selenium from selenium-rich Spirulina is less bioavailable than selenium from sodium selenite and selenomethionine in selenium-deficient rats

The bioavailabilty of selenium (Se) from selenium-rich Spirulina (SeSp) was assessed in Se-deficient rats by measuring tissue Se accumulation and glutathione peroxidase (GSH-Px) activity. For 42 d, rats were subjected to dietary Se depletion by consumption of a Torula yeast (TY)-based diet with no Se; controls were fed the same diet supplemented with 75 microg Se/kg diet as sodium selenite. Se-deficient rats were then repleted with Se (75 microg/kg) by the addition of sodium selenite, selenomethionine (SeMet) or SeSp to the TY basal diet. Selenium speciation in SeSp emphasized the quasi-absence of selenite (2% of total Se); organic Se comprised SeMet (approximately 18%), with the majority present in the form of two selenoproteins (20-30 kDa and 80 kDa). Gross absorption of Se from SeSp was significantly lower than from free SeMet and sodium selenite. SeMet was less effective than sodium selenite in restoring Se concentration in the liver but not in kidney. SeSp was always much less effective. Similarly, Se from SeSp was less effective than the other forms of Se in restoring GSH-Px activity, except in plasma and red blood cells where no differences were noted among the three sources. This was confirmed by measuring the bioavailability of Se by slope-ratio analysis using selenite as the reference form of Se. Although Se from SeSp did not replenish Se concentration and GSH-Px activity in most tissues to the same degree as the other forms of Se, we conclude that it is biologically useful and differently metabolized due to its chemical form.     

贻贝及其富硒提取物硒生物活性的比较研究

方法：用基本缺硒饲料或该饲料分别添加亚硒酸钠，胎贝和贻贝提取物饲料饲雄性鼠８周。实验４周后测每组鼠体重并进行代谢实验；收集７２ｈ尿及粪，测定硒含量；实验８周后处死大鼠，分析血及肝谷胱甘肽过氧化物酶（ＧＳＨ－Ｐｘ）活性和硒含量。结果：贻贝提取物组和贻贝组鼠血及肝ＧＳＨ－Ｐｘ活性和硒水平高于缺硒组，差异极显著；饲贻贝提取物、贻贝对提高ＧＳＨ－Ｐｘ活性的影响无较大差异；但饲贻贝提取物组鼠血及肝硒含量显著高于贻贝组和亚硒酸钠组，且贻贝提取物能有效地促进大鼠的生长。     

Comparative utilization of selenite,selenomethionine, and selenized yeast by the laying hen

Inorganic and organically-bound forms of selenium (Se) may be differentiated by monitoring the accumulation and distribution of Se in egg yolk and white of supplemented laying hens. In this experiment, the utilization of Se from a commercial selenized yeast product was compared to that of inorganic and organically-bound sources. Initially, laying hens were fed a low Se diet and then were continued on the basal diet for 4 weeks or were repleted with 0.3 or 5.0 ppm Se as sodium selenite, selenomethionine, or selenized yeast. Both the level and chemical form of dietary Se affected tissue Se concentration. Animals fed 5.0 ppm Se deposited significantly more Se in egg than hens fed 0.3 ppm Se, regardless of source. At both 5.0 and 0.3 ppm, Se from selenomethionine and selenized yeast was concentrated more effectively in egg yolk and white than the Se of sodium selenite. Based on levels of selenium accumulation and differential partitioning of Se between egg yolk and white, utilization of Se from selenized yeast more closely resembled that of selenomethionine rather than that of selenite. This bioassay may be useful for rapid preliminary speciation of Se from various dietary sources.     

黑木耳硒多糖对小鼠血脂、血硒及过氧化物酶的影响

目的　探讨黑木耳硒多糖对血脂、血硒浓度及谷胱甘肽过氧化物酶活性的影响。方法昆明系雄性小白鼠随机分成四组 :正常对照组 ( )、高脂对照组 ( )、亚硒酸钠组 ( )、硒多糖组( )。 和 组饲喂高脂饲料。并每日每鼠分别灌胃亚硒酸钠或硒多糖水溶液 1 ml(1 .95μg Se/ml) ,共 2 1 d。结果　与 组比 , 、 组小鼠血清 TC显著降低 (P<0 .0 0 1 ) ,GSH- Px活性显著增强 (P<0 .0 0 1 ) ; 组小鼠血清 TG显著降低 (P<0 .0 5) ,血硒浓度显著提高 (P<0 .0 1 ) ; 组小鼠血清 TG显著降低 (P<0 .0 1 ) ,血硒浓度显著提高 (P<0 .0 0 1 ) ;与 组比 , 组硒血浓度显著提高(P<0 .0 0 1 ) ,GSH- Px活性显著增强 (P<0 .0 1 )。结论　硒多糖较亚硒酸钠具有更好的降血脂、提高血硒浓度和增强 GSH- Px活性的作用 ,对高血脂症有一定的预防作用     

Intrinsic labeling of chicken products with a stable isotope of selenium (76Se)

Chicken tissues were intrinsically labeled with a stable isotope of selenium (76Se) and were evaluated for use in a human feeding study. Laying hens were fed a low Se (0.06 ppm) basal diet for 39 days and then fed the basal diet supplemented with 0.3 ppm enriched 76Se (as selenite) for 35 days. Incorporation of 76Se into samples was determined by use of a double isotope dilution technique and a combined gas chromatography/mass spectrometry analysis. The 76Se content of the basal diet was increased by a factor of 9.7 with the addition of the enriched stable isotope. This maximal level of enrichment was approached in egg yolk (9.5-fold) and liver (9.0-fold). Enrichment was lower in egg white (7.2-fold) and breast meat (5.0-fold). Level of enrichment in a given tissue reflected both the turnover rate of the tissue and its natural selenium content. Selenium-depleted laying hens continuously fed 76Se at the 0.3 ppm level produced egg yolks and livers that were enriched sufficiently with the stable isotope for use in a human metabolic study.     

Analysis of Bioavailability and Induction of Glutathione Peroxidase by Dietary Nanoelemental,Organic and Inorganic Selenium

Dietary organic selenium (Se) is commonly utilized to increase formation of selenoproteins, including the major antioxidant protein, glutathione peroxidase (GPx). Inorganic Se salts, such as sodium selenite, are also incorporated into selenoproteins, and there is evidence that nanoelemental Se added to the diet may also be effective. We conducted two trials, the first investigated inorganic Se (selenite), organic Se (L-selenomethionine) and nanoelemental Se, in conventional mice. Their bioavailability and effectiveness to increase GPx activity were examined. The second trial focused on determining the mechanism by which dietary Se is incorporated into tissue, utilising both conventional and germ-free (GF) mice. Mice were fed a diet with minimal Se, 0.018 parts per million (ppm), and diets with Se supplementation, to achieve 0.07, 0.15, 0.3 and 1.7 ppm Se, for 5 weeks (first trial). Mass spectrometry, Western blotting and enzymatic assays were used to investigate bioavailability, protein levels and GPx activity in fresh frozen tissue (liver, ileum, plasma, muscle and feces) from the Se fed animals. Inorganic, organic and nanoelemental Se were all effectively incorporated into tissues. The high Se diet (1.7 ppm) resulted in the highest Se levels in all tissues and plasma, independent of the Se source. Interestingly, despite being ~11 to ~25 times less concentrated than the high Se, the lower Se diets (0.07; 0.15) resulted in comparably high Se levels in liver, ileum and plasma for all Se sources. GPx protein levels and enzyme activity were significantly increased by each diet, relative to control. We hypothesised that bacteria may be a vector for the conversion of nanoelemental Se, perhaps in exchange for S in sulphate metabolising bacteria. We therefore investigated Se incorporation from low sulphate diets and in GF mice. All forms of selenium were bioavailable and similarly significantly increased the antioxidant capability of GPx in the intestine and liver of GF mice and mice with sulphate free diets. Se from nanoelemental Se resulted in similar tissue levels to inorganic and organic sources in germ free mice. Thus, endogenous mechanisms, not dependent on bacteria, reduce nanoelemental Se to the metabolite selenide that is then converted to selenophosphate, synthesised to selenocysteine, and incorporated into selenoproteins. In particular, the similar efficacy of nanoelemental Se in comparison to organic Se in both trials is important in the view of the currently limited cheap sources of Se.     

An evaluation of the bioavailability of selenium in high-selenium yeast.

The bioavailability of selenium (Se) in high-Se yeast (SeY) was evaluated by measuring tissue Se accumulation and glutathione peroxidase (GSHPx) activity. For 4 weeks, 4-week-old male Wistar rats were fed a Torula yeast-based Se-deficient diet (basal diet) or a diet supplemented with a graded level (0.04, 0.08, 0.16, and 0.32 microgram/g) of Se as either sodium selenite or SeY, which was obtained from two different sources. Se supplementation did not influence growth, hematological values, or serum biochemical tests. Se contents and GSHPx activities in the liver, serum, and erythrocytes increased gradually with increases of the supplemented Se. At lower Se levels (0.04 and 0.08 microgram/g), selenite produced higher Se deposition and higher GSHPx activities than SeY did, but at a higher Se level (0.32 microgram/g), SeY showed higher measures. Strong correlations were detected between the supplementary Se levels and the tissue Se contents or GSHPX activities when the regression was fitted to this equation: R-Rb = m log X + k, where R represented tissue Se content or GSHPx activity in rats fed the diet supplemented with Se at X level, Rb corresponding mean value in rats fed the basal diet, m slope, and k constant. The bioavailability of Se in SeY, as assessed by slope ratio analysis using selenite as a reference Se, was 135% to 165% in the tissue Se content and 105% to 197% in the GSHPx activities. These results indicate that Se in SeY is more bioavailable than selenite Se, and therefore it is the preferred form for supplementation.