硒对自身免疫性甲状腺炎大鼠甲状腺超微结构的影响

目的 观察硒干预后自身免疫性甲状腺炎(EAT)大鼠甲状腺超微结构改变,探讨硒对甲状腺自身免疫损伤反应的影响.方法建立自身免疫性甲状腺炎大鼠模型,对患病大鼠预防性和治疗性给予亚硒酸钠,观察其干预后甲状腺病理组织学变化和超微结构改变.结果实验结束时,硒预防EAT组和硒治疗EAT组TgAb、TmAb水平与EAT组相比明显下降(P＜0.05),且光镜下炎性细胞浸润明显减少,滤泡破坏减轻.电镜下EAT组大鼠主要表现为部分滤泡上皮细胞断裂,内质网高度扩张水肿,线粒体明显减少,部分线粒体嵴消失.硒预防组和硒治疗组均可见滤泡形态较规则,内质网扩张程度减轻,线粒体增多且结构趋于正常.结论 硒可预防和减轻自身免疫性甲状腺炎大鼠甲状腺的免疫性损伤.     

硒对自身免疫性甲状腺炎大鼠Nrf2表达和甲状腺细胞凋亡的影响

目的探讨硒对自身免疫性甲状腺炎(autoimmune thyroiditis,AT)大鼠Nrf2表达的影响及凋亡机制。方法通过甲状腺球蛋白免疫诱导AT大鼠模型,同时给予亚硒酸钠灌胃治疗。TUNEL染色检测甲状腺细胞凋亡情况,免疫荧光染色检测甲状腺Nrf2的表达,Western blot检测Nrf2、Bcl-2、Bax蛋白表达,同时检测各组大鼠自身抗体TGAb、TMAb水平及组织匀浆中SOD活性、MDA含量。结果 AT大鼠经过硒处理后Nrf2、Bcl-2表达及SOD活性明显增加,而Bax表达、MDA含量、TGAb、TMAb水平明显降低(均为P<0.05)。结论通过补硒可显著激活AT大鼠甲状腺Nrf2的表达,降低氧化应激水平,抑制甲状腺细胞凋亡,提示Nrf2可能通过对抗氧化应激损伤进而保护AT大鼠受损的甲状腺细胞。     

068 实验性自身免疫性甲状腺炎动物模型的建立

自身免疫性甲状腺炎是一种常见的器官特异性自身免疫性疾病,其病理特征是甲状腺组织内淋巴细胞和单核细胞浸润.实验性自身免疫性甲状腺炎(EAT)动物模型是研究自身免疫性甲状腺炎的重要工具.目前已经建立的EAT模型可分为自发产生的EAT,运用T细胞减除法产生的EAT,以及免疫方法诱导产生的EAT等几类.     

实验性自身免疫性甲状腺炎动物模型的建立

自身免疫性甲状腺炎是一种常见的器官特异性自身免疫性疾病 ,其病理特征是甲状腺组织内淋巴细胞和单核细胞浸润。实验性自身免疫性甲状腺炎 (EAT)动物模型是研究自身免疫性甲状腺炎的重要工具。目前已经建立的EAT模型可分为自发产生的EAT ,运用T细胞减除法产生的EAT ,以及免疫方法诱导产生的EAT等几类。     

实验性自身免疫性甲状腺炎动物模型的建立

自身免疫性甲状腺炎是一种常见的器官特异性自身免疫性疾病，其病理特征是甲状腺组织内淋巴细胞和单核细胞浸润。实验性自身免疫性甲状腺炎(EAT)动物模型是研究自身免疫性甲状腺炎的重要工具。目前已经建立的EAT模型可分为自发产生的EAT，运用T细胞减除法产生的EAT，以及免疫方法诱导产生的EAT等几类。     

Notch1信号通路调控γδT17细胞表达参与EAT小鼠甲状腺自身免疫损伤

为探讨γ-分泌酶抑制剂阻断Notch1信号通路对实验性自身免疫性甲状腺炎(experimental autoimmune thyroiditis, EAT)小鼠γδT17细胞表达及甲状腺自身免疫损伤的影响，将30只雌性C57BL/6小鼠随机分为正常对照(normal control, NC)组(n=10)、EAT-A组[给予猪甲状腺免疫球蛋白(porcine thyroid immunoglobulin, pTg)多点皮下注射，n=10]、EAT-B组{pTg皮下注射前给予γ-分泌酶抑制剂3,5-二氟苯乙酰-L-丙氨酰-S-苯基甘氨酸t-丁酯[N-(N-3,5-difluorophenacetyl-L-alanyl)-S-phenylglycine t-butyl ester, DAPT]腹腔注射，n=10}。应用H-E染色、ELISA、流式细胞术、qRT-PCR等评估甲状腺炎症程度，检测γδT17细胞比例及其效应细胞因子IL-17A、Notch1信号通路主要组分的表达水平。结果显示，EAT-A组小鼠血清甲状腺球蛋白抗体(thyroglobulin antibody, TgAb)滴度，...     

MHCII类分子反式激活因子突变体重组腺病毒治疗小鼠实验性自身免疫性甲状腺炎

评估IFN-γ调控型启动子(CIITA-pIV)驱动的MHC II类分子反式激活因子突变体(MHC class II transactivator mu-tant,CIITAm)重组腺病毒Ad-pIV-CIITAm对小鼠实验性自身免疫性甲状腺炎(experimental autoimmune thyroiditis,EAT)的治疗效果,并探讨其可能的作用机制。34只健康雌性CBA/J小鼠随机分成CIITAm治疗组(n=9)、GFP对照组(n=9)、EAT模型组(n=8)和正常对照组(n=8)共四组。正常对照组不做特殊处理,其余三组均以猪甲状腺球蛋白(porcinethyroglobulin,pTg)+弗氏佐剂(complete or incomplete Freund adjuvant,CFA/IFA)建立EAT小鼠模型,并分别静脉注射重组腺病毒Ad-pIV-CIITAm、Ad-GFP及等体积生理盐水。首次免疫后第29天处死小鼠,进行H-E染色观察甲状腺病理形态;免疫组织化学染色测定甲状腺MHC II类分子表达;分析pTg刺激下脾脏淋巴细胞的增殖及其上清液中IFN-γ的分泌水平;ELISA法检测血浆中抗-pTg自身抗体滴度;流式细胞术分析外周血和脾脏淋巴细胞中T细胞亚群。结果:H-E染色结果表明,CIITAm治疗组甲状腺淋巴细胞浸润指数(0.5±0.5)低于GFP对照组(1.5±0.2)和EAT模型组(1.4±0.4,P<0.01)。免疫组化结果显示,GFP对照组和EAT模型组甲状腺组织有弥漫性MHC II类分子表达,而CIITAm治疗组未见明显表达,正常对照组表达呈阴性。80μg/ml pTg刺激下,CIITAm治疗组小鼠淋巴细胞刺激指数(SI)明显低于GFP对照组或EAT模型组(P<0.01);培养上清各组IFN-γ分泌水平结果类似(P<0.01)。CIITAm治疗组血浆抗-pTg自身抗体滴度显著低于GFP对照组或EAT模型组(P<0.05);CIITAm治疗组外周血和脾脏CD4+T细胞百分率亦显著低于GFP对照组或EAT模型组(P<0.05)。重组腺病毒Ad-pIV-CIITAm能抑制EAT小鼠甲状腺组织MHC II类分子表达,抑制自身反应性T细胞增殖,减轻甲状腺炎性细胞浸润,降低自身抗体滴度,对EAT有一定的治疗作用。     

地塞米松治疗小鼠实验性自身免疫性甲状腺炎的研究

本文采用细胞培养和免疫学技术研究地塞米松对自身免疫性甲状腺炎小鼠T细胞亚群、细胞因子、甲状腺抗体滴度和甲状腺组织病理形态的影响,结果显示:(1)地塞米松能明显降低EAT小鼠TGAb、TNF和IL-1水平;(2)提高Lyt-2阳性T细胞数,降低L_3T_4/Lyt-2比值;(3)明显逆转自身免疫性甲状腺炎小鼠的病理改变。结果提示地塞米松具有调整T淋巴细胞亚群,抑制细胞因子释放,抑制甲状腺过强的自身免疫反应等作用;局部注射地塞米松治疗桥本氏甲状腺炎是一种简单、有效的好方法。     

亚硒酸钠通过线粒体途径诱导人胃癌SGC-7901细胞凋亡的机制

目的通过检测亚硒酸钠诱导人胃癌SGC-7901细胞系凋亡过程中Bax/Bcl-2、线粒体膜电位和细胞色素C(Cyt C)表达的变化,探讨亚硒酸钠诱导胃癌细胞凋亡的作用机制。方法将人胃癌细胞系SGC-7901细胞加入不同浓度亚硒酸钠(2.5、5.0、10.0mol/L)的培养液中培养24h、48h,免疫细胞化学法和免疫印迹法(Western blotting)检测Bax/Bcl-2蛋白的表达;以罗丹明123(rhodamine123)为细胞染色剂,采用流式细胞技术检测细胞的线粒体膜电位的变化;Western blotting检测细胞质Cyt C和线粒体Cyt C蛋白含量的变化。结果免疫细胞化学法和Western blotting检测结果显示,亚硒酸钠能够能够提高Bax蛋白的表达(P0.05)、降低Bcl-2蛋白的表达(P0.05),且呈剂量依懒性;流式细胞术结果显示,亚硒酸钠能够降低细胞线粒体膜电位;提示:亚硒酸钠可以通过改变Bax、Bcl-2蛋白的含量,降低线粒体的膜电位来诱导细胞凋亡。Western blotting检测结果显示,亚硒酸钠能够提高细胞质Cyt C蛋白的表达(P0.05)并降低线粒体内Cyt C蛋白的表达(P0.05),促使线粒体内的Cyt C向细胞质内释放。结论亚硒酸钠通过上调Bax并下调Bcl-2蛋白表达,降低线粒体膜电位,促进Cyt C从线粒体释放到细胞质,通过线粒体途径诱导人胃癌SGC-7901细胞凋亡。     

自身免疫性甲状腺炎 小鼠的巨噬细胞极化失衡及代谢方式改变

目的探讨巨噬细胞极化失衡及其代谢途径改变在自身免疫性甲状腺炎(AIT)发生发展中的意义。方法将4周龄NOD.H-2~(h4)雌鼠随机均分为对照组、AIT组(给予0.05%碘化钠水)。HE染色观察甲状腺组织淋巴细胞浸润情况并进行甲状腺炎性程度评分;ELISA测定血清甲状腺球蛋白抗体(TgAb);免疫荧光分析甲状腺组织中M1型和M2型巨噬细胞比例;细胞能量代谢分析仪(Seahorse)分析细胞能量代谢,测定细胞外酸化率(ECAR)、耗氧率(OCR)。结果 AIT组甲状腺组织有明显的淋巴细胞浸润,AIT的发病率明显高于对照组(P0.05)。与对照组相比,AIT组小鼠甲状腺组织中M1型巨噬细胞占比增多,M2型占比减少(P0.05);AIT组小鼠的最大ECAR和OCR值均明显高与对照组(P0.05)。结论巨噬细胞的极化失衡及其代谢改变对AIT的发生发展有着重要影响。     

Effect of sodium selenite and its combination with remantadine on the synthesis of virus-specific polypeptides in a cell culture infected with influenza A virus

The combined effects of sodium selenite and remantadine on synthesis of virus-specific polypeptides in influenza A virus-infected CEC cells are described. The pattern of selenium distribution in subcellular fractions and biomacromolecules of different organs of rats was established. Combined use of sodium selenite and remantadine actively inhibits synthesis of influenza A virus polypeptides which is of synergistic nature.     

Improved survival in murine lupus as the result of selenium supplementation.

Selenium is a trace mineral and a required nutrient for animals and humans. Selenium intake appears to be inversely correlated with the risk of developing cancer. Since immunological effects of selenium have been described we studied the capacity of selenium to modify the lupus-like disease of NZB/NZW female mice. Our data indicate that selenium supplementation (sodium selenite 4 parts per million in the drinking water) significantly improves survival in these autoimmune mice: mean survival 55.6 +/- 4.6 weeks (mean +/- s.e.) for treated mice versus 36.1 +/- 1.9 weeks for controls (P less than 0.04). Additionally, selenium supplemented mice had significantly higher natural killer cell activity (P less than 0.001). However, no obvious effects of selenium supplementation on autoantibody production were observed.     

Protective effects of selenium on methimazole nephrotoxicity in adult rats and their offspring

This study aims to investigate the improving effects of selenium on methimazole-induced kidney impairments in adult rats and their pups. The animals were randomly divided into four groups of six each: group I served as control which received standard diet; group II received only methimazole in drinking water as 250 mg/l; group III received both methimazole (250 mg/l, orally) and selenium (0.5 mg/kg of diet); group IV served as a positive control and received selenium (0.5 mg/kg of diet) as sodium selenite (Na₂SeO₃). Treatments were started from the 14th day of pregnancy until day 14 after delivery. In the methimazole-treated group, body and absolute kidney weights decreased in pups and their mothers when compared to control. Daily urine volume, plasma creatinine levels were higher, while urinary levels were lower than in control. Besides, antioxidant enzyme activities, superoxide dismutase, catalase and glutathione peroxidase decreased. Lipid peroxidation recorded an increase revealed by high kidney malondialdehyde levels, while those of plasma and urinary uric acid showed a significant decline. Methimazole-treated rat kidneys exhibited leucocytic infiltrations, vascular congestion and narrowed Bowman's space. Co-administration of selenium through diet improved all the parameters cited above in adult rats and their progeny. Nevertheless, the distorted histoarchitecture in rat kidney was alleviated by selenium treatment. It can then be concluded that selenium is an important protective element that may be used as a dietary supplement against kidney impairments.     

亚硒酸钠对大鼠胃癌变前期胃窦粘膜G、D和EC细胞的影响

目的：探讨亚硒酸钠对大鼠胃癌变前期胃窦粘膜Ｇ细胞、Ｄ细胞和ＥＣ细胞的影响。方法：用免疫组织化学及图像分析法,观察亚硒酸钠对Ｎ－甲基－Ｎ’－硝基－Ｎ－亚硝基胍诱发的大鼠胃癌变前期胃窦粘膜Ｇ细胞、Ｄ细胞和ＥＣ细胞的变化。结果：Ｎ－甲基－Ｎ’硝基－Ｎ－亚硝基胍短期灌胃后（阳性对照组）,胃窦粘膜Ｇ、Ｄ、ＥＣ细胞的数量和平均光密度值（ＯＤ值）与正常对照组比较均显著减少（Ｐ〈０．０１）。Ｎ－甲基－Ｎ’－硝基－     

Antigenotoxic properties of selenium: studies in the wing spot test in Drosophila

The genotoxic activity of three selenium compounds (sodium selenite, sodium selenate, and selenious acid) and the antigenotoxic effects of sodium selenite in combination with the chromium compound potassium dichromate were studied using the wing spot test of Drosophila melanogaster. This assay is based on the principle that the loss of heterozygosity of suitable recessive markers, multiple wing hairs (mwh) and flare-3 (flr[3]), can lead to the formation of mutant clones of larval cells, which are then expressed as spots on the wings of the adult flies. Pretreatment and chronic cotreatment was comparatively used for the antigenotoxicity study. From the results obtained, it was evident that all selenium compounds are unable to increase the frequency of any of the three categories of spots recorded (small, large, and twin spots). Nevertheless, the antigenotoxic effects of sodium selenite were clearly demonstrated, in both cotreatment and pretreatment, by a complete suppression of those clones induced by potassium dichromate. Therefore, the D. melanogaster wing spot test was revealed to be a good assay, not only for evaluating genotoxic activity but also for detecting antigenotoxic effects in vivo.     

Hepatoprotective role and antioxidant capacity of selenium on arsenic-induced liver injury in rats

The present study was undertaken to evaluate the protective effect of selenium against arsenic-induced oxidative damage in experimental rats. Males were randomly divided into four groups where the first was served as a control, whereas the remaining groups were respectively treated with sodium selenite (3 mg/kg b.w.), sodium arsenite (5.55 mg/kg b.w.) and a combination of sodium arsenite and sodium selenite. Changes in liver enzyme activities, thiobarbituric acid reactive substances (TBARS) level, antioxidants and reduced glutathione (GSH) contents were determined after 3 weeks experimental period.Exposure of rats to As caused a significant increase in liver TBARS compared to control, but the co-administration of Se was effective in reducing its level. The activities of glutathione peroxidase (GPx) and glutathione-S-transferase (GST) of As-treated group were found lower compared to the control and the Se-treated group. The co-administration of Se had an additive protective effect on liver enzyme activities compared to As-treated animals. On the other hand, a significant increase in plasmatic activities of AST, ALT and ALP was observed in As-treated group. The latter was also exhibited a decrease in body weight and an increase in liver weight compared to the control. The co-administration of Se has decreased the activities of AST, AST and ALP and improved the antioxidant status as well. Liver histological studies have confirmed the changes observed in biochemical parameters and proved the beneficial role of Se. To conclude, results suggest that As exposure enhanced an oxidative stress by disturbing the tissue antioxidant defense system, but the Se co-administration protected liver tissues against As intoxication probably owing to its antioxidant properties.     

Light and electron microscopical visualization of selenium in adrenal glands from rats exposed to sodium selenite

A histochemical study was performed to determine the cellular localization of selenium in the adrenals from rats exposed to sodium selenite, as these organs were known to obtain the highest concentration in the rats. Male rats were treated either with 1-15 mg of sodium selenite for 14 days to 6 months in the drinking water, or with 1-20 mg as intraperitoneal injections. Selenium was shown to accumulate in both norepinephrenic and epinephrenic cells in a dose-dependent fashion. After oral exposure most deposits were found in the epinephrenic cells, whereas the norepinephrenic cells contained most in the injected animals. Fourteen days after a single injection (4 mg/kg), deposits could still be observed in the granules of the chromaffin cells. At the ultrastructural level, accumulations were primarily found in the chromaffin granules and to a lesser extent in the lysosomes. Selenium may possibly form bonds to endogenous zinc in the adrenals as has been suggested for the brain.     

Reduction in experimental autoimmune thyroiditis by IgG Fc fragments bearing regRF epitopes

Previously, we identified a new immunoregulatory factor, the production of which provides rats with resistance to certain experimental autoimmune diseases. It has been named regulatory rheumatoid factor (regRF). RegRF inhibits the expansion of CD4 T lymphocytes by killing activated cells. CD4 T cells are essential for antibody production against a majority of antigens and for the generation of cytotoxic T cells; therefore, regRF is an attractive therapeutic biotarget for T-cell and antibody-mediated autoimmune diseases. RegRF is anti-idiotypic antibodies that have a shared paratope in addition to an individual paratope. Epitopes specific to the shared regRF paratope (regRF epitopes) can be obtained on conformers of IgG Fc fragments. Immunization with Fc fragments carrying regRF epitopes reduces rat collagen–induced arthritis and diminishes experimental autoimmune encephalomyelitis. The aim of this study was to determine whether IgG Fc fragments bearing regRF epitopes suppress experimental autoimmune thyroiditis (EAT). Four weeks after EAT induction, rats were immunized with IgG Fc fragments exhibiting regRF epitopes. Histology studies of the thyroid were performed 4 weeks later. Thyroid function and other parameters were also evaluated. Treatment of rats with Fc fragments bearing regRF epitopes decreased the number of rats affected by EAT, significantly decreased the extent of thyroid damage, prevented thyroid metaplasia, and restored normal thyroid hormone production. Therefore, RegRF is a promising biotarget in autoimmune thyroiditis, and Fc fragments bearing regRF epitopes are a potential therapeutic agent for that condition.

     

硒对氧化偶氮甲烷所致结肠癌模型大鼠睾丸精原细胞P16蛋白表达的影响

目的观察硒对氧化偶氮甲烷（AOM）所致结肠癌大鼠睾丸精原细胞P16蛋白表达的影响.方法随机将20只3周龄断乳雄性SD大鼠分为：正常对照组、实验对照组、AOM致癌前喂食亚硒酸钠水组、AOM致癌后喂食亚硒酸钠水组.每周腹腔注射AOM 15 mg/kg,持续2周,造成大鼠结肠癌模型.用4 mg/L Na2SeO3水溶液分别在AOM致癌前、后开始进行干预,并持续至实验结果.各组均于34周后取两侧睾丸,用免疫组织化学方法,观察大鼠睾丸精原细胞内P16蛋白的表达,并进行图像分析.结果正常组大鼠的睾丸内未见精原细胞表达P16蛋白,而实验对照组、硒干预AOM致癌组（AOM致癌前、后喂食亚硒酸钠水）的精原细胞P16均呈阳性表达,阳性产物呈深棕色,定位于细胞核中,细胞质内仅有少量表达.实验对照组、AOM致癌前、后喂食亚硒酸钠水组阳性表达逐渐增强,组间具有显著性差异（P〈0.05）.结论硒可增强AOM所致结肠癌大鼠精原细胞P16蛋白的表达.