摘要
目的构建实验性自身免疫性甲状腺炎(EAT)大鼠模型,探讨不同碘摄入量所致的EAT大鼠对其后代海马组织形态、脑内单胺类神经递质及行为学的影响。方法选取雌性Lewis大鼠60只、雄性20只,体质量为50~60 g。雌鼠按体质量采用随机数字表法分为4组(每组15只):对照组(NI组)、甲状腺球蛋白组(Tg组)、Tg+高碘Ⅰ组(Tg+HⅠ组)、Tg+高碘Ⅱ组(Tg+HⅡ组),后3组为模型组。4组大鼠饮水碘含量分别为100μg/L、100μg/L、20 mg/L和200 mg/L。模型组采用猪甲状腺球蛋白(PTg)皮下多点注射免疫,NI组注射生理盐水,2周1次,共3次;各组大鼠按雌雄3∶1的比例合笼交配。仔鼠实验后,前1周内收集母鼠尿样,采用砷铈催化分光光度法测定母鼠尿碘含量;处死母鼠,HE染色观察母鼠甲状腺组织形态学改变和炎细胞浸润程度;放射免疫分析法测定母鼠血清甲状腺球蛋白抗体(TgAb)、甲状腺过氧化物酶抗体(TPOAb)水平。采集出生7 d仔鼠脑组织,甲苯胺蓝染色观察出生7 d仔鼠脑海马组织形态;酶联免疫吸附试验(ELISA)测定出生7 d仔鼠脑组织去甲肾上腺素(NE)、多巴胺(DA)和5-羟色胺(5-HT)含量;出生30、60 d仔鼠进行水迷宫-定位航行实验和旷场实验。结果Tg+HⅠ、Tg+HⅡ组母鼠尿碘水平明显高于NI组(中位数,μg/L:35380.18、236847.16比221.43,P均<0.05)。HE染色显示,Tg、Tg+HⅠ、Tg+HⅡ组母鼠甲状腺组织均有不同程度的破坏和炎性细胞浸润,且随着摄碘量的增加其破坏及浸润程度加重。Tg、Tg+HⅠ、Tg+HⅡ组母鼠血清TgAb、TPOAb含量与NI组相比显著升高(2.1184±0.6751、2.1030±0.7141、2.7836±1.0843比0.7901±0.1010,1.0158±0.2528、1.0195±0.2020、0.9366±0.1834比0.6922±0.1119,P均<0.05),且Tg+HⅡ组母鼠血清TgAb含量明显高于Tg、Tg+HⅠ组(P均<0.05)。与NI组相比,Tg、Tg+HⅠ、Tg+HⅡ组仔鼠脑海马神经元数量减少以及出现相对损伤。Tg、Tg+HⅠ、Tg+HⅡ组仔鼠脑组织NE含量与NI组相比明显下降(pg/ml:1232.01±253.45、1197.64±222.46、1074.40±366.38比1733.67±158.12,P均<0.05);各组仔鼠脑组织DA、5-HT含量比较差异无统计学意义(P均>0.05)。水迷宫-定位航行实验,出生30 d仔鼠第4天Tg+HⅡ组到达平台的潜伏期明显长于NI和Tg组(P均<0.05);旷场实验,出生30、60 d各组仔鼠逃离原始象限的潜伏期比较差异无统计学意义(P均>0.05)。结论随着碘摄入量的升高,EAT大鼠甲状腺组织破坏程度及炎性浸润程度加重,TgAb含量明显升高。碘对EAT大鼠子代脑海马组织形态以及单胺类神经递质含量有一定影响。不同碘摄入量对EAT大鼠后代学习记忆以及空间探索能力的影响主要表现在幼年时期。
Objective By establishing a rat model of experimental autoimmune thyroiditis(EAT),to investigate the effects of different iodine intake on the hippocampal morphology,monoamine neurotransmitters and ethology of the offspring of EAT rats.Methods A total of 60 female and 20 male Lewis rats with a body weight of 50-60 g were selected.Female rats were divided into 4 groups(15 rats in each group)with random number table method according to their body weight:control group(NI group),thyroglobulin group(Tg group),Tg+high iodineⅠgroup(Tg+HⅠgroup),and Tg+high iodineⅡgroup(Tg+HⅡgroup),and the latter three groups were model groups.The contents of iodine in drinking water of the 4 groups were 100μg/L,100μg/L,20 mg/L and 200 mg/L,respectively.Rats in the model groups were immunized with porcine thyroglobulin(PTg)subcutaneously at multiple sites,and the NI group was injected with normal saline,once every 2 weeks,3 times in total.The rats in each group were mated in cages according to the ratio of 3:1 between female and male.After experiment of the offspring,the urine samples of mother rats were collected within the previous week,urinary iodine concentration was determined by As3+-Ce4+catalytic spectrophotometry;then the mother rats were killed,HE staining was used to observe the changes of thyroid histomorphology and the infiltration of inflammatory cells;serum thyroglobulin antibody(TgAb)and thyroid peroxidase antibody(TPOAb)of mother rats were determined by radioimmunoassay.Brain tissues were collected from 7 days old offspring,hippocampal morphology of 7 days old offspring was observed by toluidine blue staining;the contents of norepinephrine(NE),dopamine(DA)and 5-hydroxytryptamine(5-HT)in brain tissues of 7 days old offspring were measured by enzyme-linked immunosorbent assay(ELISA);30 and 60 days old offspring were used for water maze-location navigation test and open field test.Results The levels of urinary iodine increased significantly of mother rats in Tg+HⅠand Tg+HⅡgroups than that in NI group(median,μg/L:35380.18,236847.16 vs 221.43,P<0.05).HE staining showed that the thyroid tissue of mother rats in Tg,Tg+HⅠand Tg+HⅡgroups had different degrees of destruction and inflammatory cells infiltration,and the degree of destruction and infiltration increased with the increase of iodine intake.Compared with NI group,the contents of TgAb and TPOAb in serum of mother rats in Tg,Tg+HⅠand Tg+HⅡgroups were significantly increased(2.1184±0.6751,2.1030±0.7141,2.7836±1.0843 vs 0.7901±0.1010,P<0.05;1.0158±0.2528,1.0195±0.2020,0.9366±0.1834 vs 0.6922±0.1119,P<0.05),and the content of TgAb in Tg+HⅡgroup was significantly higher than that in Tg and Tg+HⅠgroups(P<0.05).Compared with NI group,the number of hippocampal neurons decreased and relative damage occurred in Tg,Tg+HⅠand Tg+HⅡgroups of the offspring.Compared with NI group,the NE contents in brain tissues of the offspring in Tg,Tg+HⅠand Tg+HⅡgroups decreased(pg/ml:1232.01±253.45,1197.64±222.46,1074.40±366.38 vs 1733.67±158.12,P<0.05);there were no significant differences in DA and 5-HT contents in brain tissues of offspring in each group(P>0.05).In the water maze-location navigation test,the latency of the Tg+HⅡgroup on the 4th day of the 30 days old offspring reaching the platform was significantly longer than that of the NI and Tg groups(P<0.05).In the open field test,there was no significant difference in 30 and 60 days old offspring in the latency of moving the original quadrant(P>0.05).Conclusions With the increase of iodine intake,the degrees of thyroid tissue destruction and inflammatory cells infiltration in EAT rats increase,and the levels of TgAb in serum increase significantly.Iodine has certain effects on the hippocampal morphology and the level of monoamine neurotransmitters in the brains of the offspring of EAT rats.The effects of different iodine-induced EAT rats on their offspring's learning,memory and spatial exploration are mainly shown in childhood.
作者
金美慧
周正
张黎
陈瑶
刘丽香
申红梅
Jin Meihui;Zhou Zheng;Zhang Li;Chen Yao;Liu Lixiang;Shen Hongmei(Institute of Iodine Deficiency Disorders,Center for Endemic Disease Control,Chinese Center for Disease Control and Prevention,Harbin Medical University,Harbin 150081,China;Center for Endemic Disease Control,Chinese Center for Disease Control and Prevention,Harbin Medical University,Harbin 150081,China)
出处
《中华地方病学杂志》
CAS
CSCD
北大核心
2020年第7期469-476,共8页
Chinese Journal of Endemiology
基金
国家自然科学基金(81703175)。
