BN大鼠致敏动物模型研究

验证BN大鼠作为评价转基因食物蛋白致敏性动物模型的可行性。方法 48只雌性BN大鼠随机分为对照组(灭菌水)、马铃薯酸性磷酸酶组(PAP)、鸡蛋清粗提蛋白质组(HEWP)、卵清蛋白低剂量组(OVA-L)、卵清蛋白中剂量组(OVA-M)、卵清蛋白高剂量组(OVA-H),每组8只。各组依次分别每天经口灌胃1ml灭菌水、1mg/ml PAP、10mg/ml HEWP、0.1mg/ml OVA、1mg/ml OVA、10mg/ml OVA溶液,持续6周。分别于第14、28和42天取血分离血清,测定特异性抗体IgG和血清总IgE。于第21和35天取血分离血浆,测定组胺。测定各组动物的血压变化及胃肠道渗透性。结果 不同浓度致敏原OVA均可激发BN大鼠过敏反应,包括特异性IgG和血清总IgE升高、组胺升高以及血压下降,其中1mg/ml OVA溶液为致敏最佳剂量。弱致敏原HEWP过敏反应较弱;非致敏原PAP无过敏反应;各组胃肠功能均未发生明显的生理变化。结论 BN大鼠致敏动物模型是评价转基因食物致敏性较为理想的动物模型。     

BN大鼠致敏动物模型研究

目的 研究BN大鼠作为评价食物蛋白质过敏性动物模型的可行性.方法 通过经口和腹腔注射2种途径给予BN大鼠致敏原和非致敏原.(1)30只雌性BN大鼠,随机分为卵清蛋白(OVA)组、马铃薯酸性磷酸酶(PAP)组和阴性对照组,每组10只.OVA组和PAP组分别每日1次经口灌胃给予1 mg/ml OVA、PAP 1 ml,对照组灌同剂量的生理盐水,共42 d.(2)40只雌性BN大鼠,随机分为OVA组、OVA+AI(OH)3(佐剂)组、PAP组和阴性对照组,每组10只.OVA组、OVA+Al(OH)3组和PAP组在试验第1、5、10天分别经腹腔注射剂量0.1 mg/ml的OVA溶液、含Al(OH)3的OVA溶液(OVA+Al(OH)3=1+1)、PAP溶液1 ml,观察42 d.对照组腹腔注射同剂量的生理盐水.于第14、28和42天取血分离血清,测定特异性抗体IgG和IgE.于第21和35天取血分离血浆,测定组胺.测定各组动物的血压变化及胃肠道渗透性.结果 致敏原OVA可激发BN大鼠的过敏反应,包括部分大鼠血压的暂时性下降、特异性抗体(尤其是特异性IgE)升高、组胺升高和部分大鼠的胃肠道通透性增加,而非致敏原PAP反应阴性.结论 BN大鼠致敏动物模型是比较理想的评价食物蛋白质过敏性的动物模型.     

利用BN大鼠动物模型评价S86转基因大米的致敏性

为研究S86转基因大米的致敏性,用BN大鼠致敏动物模型进行研究.40只BN大鼠随机分为4组,每组10只,分别为:阳性对照组,转基因大米组,非转基因大米组及阴性对照组.分别在第0和第7天,通过腹腔注射给予阳性对照组的大鼠0.1 mg/ml卵清蛋白(OVA)1ml,其它各组在相同时间腹腔注射相同剂量的生理盐水.以AIN-93G为依据配制各组饲料,阳性对照组和阴性对照组大鼠饲以AIN-93G饲料,转基因大米组饲以含转基因大米粉的饲料,非转基因大米组饲以含非转基因大米粉的饲料,时间为6周.在第2次腹腔注射OVA后,取血分离血浆进行组胺测定.分别在第14、21、28、35、42天取血分离血清,测定IgG及IgE水平;此外,分别在实验前和实验后测定各组大鼠的血压.血清学实验结果显示转基因大米全食品喂饲没有激发IgG及IgE反应,而OVA(阳性对照组)激发了明显的IgG及IgE反应;转基因大米组的组胺水平与阴性对照组及亲本对照组相比差异没有显著性,而阳性对照组组胺水平升高.另外转基因大米没有引起大鼠血压升高.该研究结果表明通过全食品喂饲的方式给予BN大鼠S86转基因大米没有发现该转基因大米对BN大鼠具有致敏性.     

利用BN大鼠致敏模型研究HPT蛋白的致敏性

目的用BN大鼠致敏模型对HPT(潮霉素B磷酸转移酶)蛋白的致敏性进行研究。方法40只BN大鼠随机分为4组,每组10只,分别经口灌胃给予卵清蛋白(OVA)(阳性对照组)、HPT蛋白(HPT蛋白组)、马铃薯酸性磷酸酶(PAP)(阴性对照组)及蒸馏水(溶剂对照),剂量均为1 mg/ml,每只动物1 ml,每日1次,连续28 d。于灌胃后第7天,取血分离血浆进行组胺测定。于第14天和第28天取血分离血清测定IgE水平。于试验结束后第10天分别对各组动物进行大剂量(5 mg/ml OVA、HPT、PAP或蒸馏水,2 ml/只)激发后测定各组大鼠的血压。结果血清学实验结果表明HPT蛋白没有激发任何IgE反应,而OVA激发了明显的IgE反应;HPT组的组胺水平与阴性对照组或溶剂对照组相比差异无统计学意义,而阳性对照组组胺水平升高,与HPT蛋白组相比差异有统计学意义(P<0.05)。OVA导致3只大鼠血压暂时降低,而HPT对大鼠血压没有影响。结论在该实验条件下,经口灌胃给予BN大鼠HPT蛋白,没有发现致敏性。     

BN大鼠经口致敏动物模型研究

目的 建立经口灌胃途经给予造模致敏原的挪威棕色(Brown Norway,BN)大鼠致敏动物模型.方法 选用不同周龄(4周龄和8周龄)及不同性别(雄性和雌性)的BN大鼠,每天经口灌胃给予不同剂量(10.0、1.0、0.1mg)的造模致敏原—卵清蛋白(OVA),共35天.在第28和35天分别进行内眦静脉取血并分离血清,采用酶联免疫吸附测定(ELISA)方法检测血清中OVA特异性IgE(OVA sIgE)浓度.结果 中剂量组雌性4周龄和8周龄BN大鼠血清中OVA sIgE浓度在第28和35天较阴性对照组差异有统计学意义(P＜0.05);低剂量组雄性8周龄BN大鼠血清中OVA sIgE浓度在第28天较阴性对照组差异有统计学意义(P＜0.05);各组雄性4周龄BN大鼠血清中OVA sIgE浓度在第28和35天均较阴性对照组差异无统计学意义.结论 经口灌胃途径给予不同性别和周龄的BN大鼠不同剂量的OVA,雌性大鼠比雄性大鼠更敏感;周龄对敏感性无影响;1.0 mg的致敏剂量较适合.因此,选用雌性BN大鼠,每天经口灌胃给予1.0 mg OVA,28 ～ 35天即可建立比较理想的BN大鼠经口致敏动物模型.     

维生素E对致敏大鼠机体敏感性的影响

目的研究补充不同剂量、不同接触时间的维生素E对致敏SD大鼠机体敏感性的影响。方法取8周龄雌性SD大鼠,按体重随机分为5组,每组25只,每天经口分别给予不同剂量的维生素E(2.3、6.9、13.8mg/kg),在第2周、3周、4周、5周、6周时,每组分别取出5只动物,腹腔注射给予10 mg/只OVA致敏,一周后使用50 mg/只OVA刺激,检测各组动物血清中总Ig E、特异性Ig E和Ig G1、血浆中组胺、m MCP-1和细胞因子(IFN-γ,IL-4)的水平,大刺激后处死动物,取心脏、肝、脾、肾、胸腺、空肠、肠系膜淋巴结等脏器,并对这些脏器进行组织病理学观察。结果经口给予高剂量维生素E 6周,OVA产生的免疫学反应强度受到了显著的抑制作用,总Ig E、特异性Ig E、特异性Ig G1、IL-4以及组胺水平显著降低,IFN-γ水平显著升高,随接触时间的延长呈增高的趋势。且高剂量处理组动物免疫学反应强度显著低于OVA对照处理组,对致敏SD大鼠的机体敏感性起到了有效的调节作用。结论维生素E能够降低致敏动物机体对卵白蛋白的敏感性,也抑制了免疫系统对卵白蛋白产生的免疫学反应。     

主要坚果类过敏原致敏机理的初步探讨

本文以坚果过敏蛋白为抗原,构建小鼠动物致敏免疫模型,探讨坚果过敏原的致敏机理,为坚果类食物安全评价和安全开发提供有效的实验依据。选取六种坚果为原料,以昆明小鼠为受试小鼠,坚果蛋白液以0.01 mg/g进行灌胃致敏,第33 d和34 d以0.02 mg/g激发致敏,通过测定小鼠血清IgE、IgG、腹腔肥大细胞及类胰蛋白酶和血象指标,研究其病理特征。结果表明,致敏激发后小鼠IgE与IgG最高水平为0.91和0.93,组胺释放率阳性组为58%,中剂量组为40%,高剂量组为55%;小鼠腹腔肥大细胞体外激发后脱颗粒高剂量组最多以及类胰蛋白酶活性也最高;中和高剂量组、阳性组白细胞数较高(9.7±6.1、9.6±2.4、9.2±2)×109/L,低剂量组、中剂量组和高剂量组的血小板数依次降低。说明致敏后小鼠凝血功能显著减弱,免疫系统受到侵袭,体内诱发产生IgE抗体,并启动过敏介质的释放机制,导致过敏反应Ⅰ型变态反应的发生。     

BN大鼠食物过敏动物模型的实验研究

为了解挪威棕色大鼠(BN)作为食物过敏动物模型的可行性。将24只BN大鼠随机分为灭菌水组(对照组)、卵清蛋白组(Ovalbumin，OVA)、马铃薯酸性磷酸酶组(Potato acid plaosplaatase，PAP)、鸡蛋清粗提蛋白质组(hen’s egg-white protein，HEWP)，每组6只。对各组大鼠灌胃，1ml／只，OVA、PAP组蛋白质浓度为1mg／ml,HEWP组蛋白质浓度为10．0mg／ml，每天1次．共6周。检测血清中特异IgE抗体滴度，同时进行皮肤过敏反应试验(PCA)。在第28、42天，OVA、HEWP组BN大鼠32倍稀释血清中特异IgE抗体均较对照组升高，并有统计学差异，第14、28、42天的：PAP组及第14天的OVA、HEWP组BN大鼠32倍稀释血清中特异IgE抗体较对照组相比无统计学差异。BN大鼠对常见致敏食物蛋白质OVA和HEWP产生过敏反应，对无致敏史食物蛋白质PAP无过敏反应。BN大鼠模型可能是较为理想的食物过敏动物模型。     

大米蛋白的BN大鼠致敏动物模型建立

以大米蛋白为过敏原,腹腔注射致敏雌性棕色挪威大鼠(BN大鼠),建立大米蛋白过敏BN大鼠动物模型。观察BN大鼠全身主动过敏反应及体重、体温、免疫脏器指数变化,检测其血清特异性Ig G、总Ig E和特异性Ig E水平,并测定血浆组胺释放水平及各组大鼠的血象变化。结果显示,实验第42 d大米蛋白激发实验后,实验组大鼠全部呈过敏反应阳性,且体温降低,脾脏指数显著增大(p0.01),体内白细胞和嗜酸粒细胞数目升高(p0.05);实验组血清特异性Ig G显著升高(p0.01),总Ig E以及血浆组胺释放量均高于对照组(p0.05),实验第14 d和42 d血清特异性Ig E高于对照组,第28 d无明显变化(p0.05)。本实验结果证明BN大鼠是评价大米蛋白致敏性较为理想的动物模型。     

牡蛎Cra g 1蛋白大鼠致敏模型的建立与分析

为了建立并分析牡蛎致敏大鼠模型,利用牡蛎过敏原Cra g 1,通过灌胃和腹腔注射相结合的方式致敏雌性棕色挪威大鼠(BN大鼠)。观察各组BN大鼠过敏反应及体重、体温、脏器指数、血象指标变化;通过ELISA法检测抗体、组胺变化;通过苏木精-伊红(HE)及甲苯胺蓝染色观察组织器官变化。结果显示,实验组动物均发生过敏反应,对照组无明显症状;实验组动物体重显著低于对照组,脏器指数显著高于对照组,血液中细胞数量发生变化;另外,致敏期间实验组抗体及组胺水平均高于对照组;染色结果表明实验组大鼠脏器出现明显的病变损伤,肠道肥大细胞脱颗粒现象严重。该研究获得了Cra g 1蛋白致敏血清,同时证明BN大鼠是良好的动物致敏模型,为研究食物过敏原致敏机制及其体内免疫调节提供较好的依据。     

The impact of transgenic papaya (TPY10-4) fruit supplementation on immune responses in ovalbumin-sensitised mice

BACKGROUND: A transgenic papaya line (TPY10‐4) that is resistant to both papaya ringspot virus (PRSV) and papaya leaf distortion mosaic virus (PLDMV) has been developed in Taiwan. This study investigated the immunomodulatory properties of transgenic TPY10‐4 and its native (TCK) papaya fruits using an ovalbumin (OVA)‐sensitised mouse model. Both green and ripe papaya fruits at low (0.2 g powder kg^?1 body weight (BW)) and high (1.6 g powder kg^?1 BW) doses were administered to experimental mice by intragastric gavage for 5 weeks. Changes in serum total immunoglobulin A (IgA), IgE, IgG and IgM levels, OVA‐specific IgE, IgG1 and IgG2a titres and Th1/Th2 cytokine secretions using splenocytes were determined. RESULTS: Transgenic TPY10‐4 or native TCK papaya fruit supplementation did not significantly affect body, visceral organ and relative tissue weights, total IgE antibody levels, OVA‐specific IgE and IgG1 antibody titres or OVA‐stimulated interferon‐γ (IFN‐γ), interleukin‐2 (IL‐2), IL‐4, IL‐5 and IL‐10 secretions using splenocytes. However, transgenic papaya fruits markedly increased serum total IgM levels. CONCLUSION: This study suggests that transgenic TPY10‐4 papaya fruits do not increase the allergenic potential of OVA by oral administration but may have a protective immunity via increasing the serum total IgM level. Copyright © 2010 Society of Chemical Industry     

Change of an egg allergen in a white layer cake containing gamma-irradiated egg white

This study was conducted to evaluate the reduction of an egg allergen in a cake containing gamma-irradiated egg white. A white layer cake was manufactured by a commercial formula with 10- or 20-kGy-irradiated egg white. Enzyme-linked immunosorbent assays (ELISAs) with immunoglobulin (Ig) E from egg-allergic patients and with rabbit anti-ovalbumin IgG were used to identify and quantify ovalbumin (OVA) in the samples. Concentrations of native OVA detected by IgE and IgG in the control were 432.88 and 375.46 microg/g sample, respectively. However, native OVA in samples with 10- and 20-kGy-irradiated egg white was detected at low concentrations (14.27 and 8.78 microg/g, respectively) by IgE (P < 0.05); IgG recognized OVA more often in 10- and 20-kGy samples than in controls. Conformational cleavage of OVA by irradiation could explain the IgG result. The results appear to suggest that irradiating egg white might reduce its allergenicity, which could be used in the production of baked goods of reduced allergenicity.     

The anti‐allergenic properties of milk kefir and soymilk kefir and their beneficial effects on the intestinal microflora

Food allergy is now recognized as a worldwide problem, and like other atopic disorders its incidence appears to be increasing. Kefir is reported to possess the ability to reduce intestinal permeation of food antigens; however, no experimental study has clearly evaluated the relationships between kefir consumption, allergen‐specific IgE response, and intestinal microflora. The aim of this study was to evaluate the effect of oral consumption of milk kefir and soymilk kefir on in vivo IgE and IgG1 production induced by ovalbumin (OVA) in mice. The effects of kefir administration on the murine intestinal microflora were also examined. Oral administration of milk kefir and soymilk kefir for 28 days significantly increased the fecal populations of bifidobacteria and lactobacilli, while it significantly decreased those of Clostridium perfringens. Milk kefir and soymilk kefir also significantly decreased the serum OVA‐specific IgE and IgG1 levels for both groups, but not those of the IgG2a analogues. Consumption of milk kefir and soymilk kefir suppressed the IgE and IgG1 responses and altered the intestinal microflora in our supplemented group, suggesting that milk kefir and soymilk kefir may be considered among the more promising food components in terms of preventing food allergy and enhancement of mucosal resistance to gastrointestinal pathogen infection. Copyright © 2006 Society of Chemical Industry     

Identification of the Critical Amino Acid Residues of Immunoglobulin E and Immunoglobulin G Epitopes in α‐Lactalbumin by Alanine Scanning Analysis

α‐Lactalbumin represents one of the major allergens causing cow milk allergy. Few studies have clearly evaluated immunological relationships between immunoglobulin E (IgE) and immunoglobulin G (IgG)‐binding epitopes of α‐lactalbumin. IgE‐ and IgG‐binding epitopes were immunolabeled with individual sera from cow milk‐allergic patients. Alanine scanning of immunodominant epitopes was used to identify the critical amino acid (aa). Our initial data revealed Val⁸, Phe⁹, Arg¹⁰, Tyr¹⁰³, Leu¹⁰⁵, and His¹⁰⁷ were the critical aa for IgE‐binding epitope. The critical aa of IgG‐binding epitopes were Phe⁹, Leu¹⁵, Pro²⁴, Trp²⁶, and His³². This study will provide necessary information to alter the cDNA to encode a protein capable of activating milk‐specific T cells, but with reduced IgE‐ or IgG‐binding capacity.     

Hypocholesterolemic Properties of Protein Isolate from Cowpeas (Vigna Unguiculata) Sprout in Normal and Diabetic Rats

This research was aimed to determine the potency of hypocholestrolemic properties of protein isolate from cowpeas sprout through in vivo bioassay by using Sprague Dawley male rats. The treatments of the research were rat conditions (normal and diabeic rats) and feed treatments (standard and protein isolate feed). Blood triglyceride, cholesterol total, High Density Lipoprotein (HDL), and Low Density Lipoprotein (LDL), of rats were analysed on 3^th, 6 ^th, 9 ^th, 12 ^th, 15 ^th days for the treatment and before treatment as control. The result of this research showed that the blood triglyceride, cholesterol total, LDL decreased and the blood HDL increased in diabetics rats with protein isolate treatment. The potency of hypocholestrolemic activity were shown by the ratio of cholesterol total/HDL and LDL/HDL. The ratio of the rats were normal, exception diabetic rats with standart feed.     

Effect of subchronic feeding of genetically modified corn (CBH351) on immune system in BN rats and B10A mice

Subchronic animal feeding studies to examine the effect on the immune system of genetically modified corn CBH351, which contains the Cry9C protein derived from Bacillus thuringiensis subspecies tolworthi, were conducted in female BN rats and B10A mice. The studies were designed to compare the effect of a line of genetically modified corn CBH351 (GM corn) with that of isoline corn (non-GM corn). Heat-treated corn meal was incorporated into the diets of the rats and mice at a concentration of 50%. The study duration was 13 weeks. Growth, food intake, and organ weights of the thymus, spleen, and liver were compared between animals fed the non-GM and GM lines. The histological findings in thymus, spleen, mesenteric lymph nodes, Peyer's patches, small intestines, liver, kidney, and bone marrow, and the presence of Cry9C-specific IgE, IgG, IgG1 and IgA antibodies in serum were also compared. The results showed no significant differences in growth, feeding value, or the histological findings in immunity-related organs between the animals fed the GM and non-GM lines. Production of Cry9 C-specific IgE and IgA was not detected in the serum of either group. Production of Cry9C-specific IgG and IgG1 was slightly increased in the 50% GM groups of BN rats. No Cry9C-specific IgG or IgG1 was detected in the serum of BN rats fed the diet containing 5% GM-corn In conclusion, no immunotoxic activity was detected in the GM-corn-fed rats and mice in this subchronic dietary study.     

转Bt玉米暴露对亲代及子代大鼠免疫细胞分型及细胞因子的影响

为研究转苏云金芽胞杆菌(Bacillus thuringiensis,Bt)基因抗虫玉米长期食用对大鼠免疫的影响,以其亲本非转基因玉米饲料及商业饲料为对照,分别采用流式细胞术及液相芯片法检测喂养90 d后亲代及子代刚断乳大鼠外周血、脾脏免疫细胞分型及相关血清细胞因子的表达。结果发现,转Bt基因抗虫玉米饲料组亲代大鼠外周血和脾脏及子代脾脏各淋巴细胞亚群(CD4~+、CD8~+、TCRαβ~+、TCRγδ~+)的细胞数量比例及亲代血清中10种细胞因子表达水平均与非转基因玉米饲料组无显著差异(P0.05);子代外周血B淋巴细胞数量比例显著增高,巨噬细胞炎症蛋白-1α、单核细胞趋化因子-1β、白细胞介素-5表达水平明显降低(P0.05)。结果表明:转Bt基因抗虫玉米暴露90 d对亲代大鼠免疫系统影响不大;对子代刚断乳大鼠的细胞免疫及体液免疫有一定的影响。     

杭菊花乙醇提取物对大鼠生殖发育毒性研究

目的研究杭菊花乙醇提取物(CME)经过亲代、宫内、哺乳期和断乳后持续暴露对子代的影响。方法设对照组和CME低、中和高剂量组,CME掺入饲料,剂量分别为0、1、3、9 g/kg BW;参照OECD TG 443开展一代延长试验,每组孕鼠20只及其子鼠每组40只(雌雄各半),子鼠断乳后持续给予CME 13周,测定生长发育、生殖发育、血象、血生化指标,做组织病理学检查。结果 CME高、中剂量组子鼠睁眼时间明显迟于对照组;低剂量组子代雌性大鼠出生后(PND)56～112天体质量明显高于对照组,子代雌性大鼠CME高、低剂量组红细胞计数(RBC)和血红蛋白浓度(HGB)均降低,CME高剂量组谷丙转氨酶(ALT)升高,高、中剂量组谷草转氨酶(AST)、血磷(P)升高,CME各剂量组血糖(GLU)均降低、乳酸脱氢酶(LDH)均升高;子代雄性大鼠CME高、低剂量组血清钾(K~+)降低;子代雌雄大鼠CME高剂量组脾脏/体质量系数均高于对照组;以上均差异有统计学意义(F=2.818～42.75,P0.05)。结论低剂量CME促进子代雌性大鼠体质量生长发育,降低子代雌性大鼠的血糖,影响RBC、HGB和LDH;高、中剂量CME影响子代大鼠发育和子代雌性大鼠的肝功能,高剂量CME影响子代雌雄大鼠脾脏/体质量系数。