IGF-1、TGF-β1在碘缺乏和碘过量所致甲状腺形态及功能变化中的可能作用

发布时间：2018-05-25 22:24

本文选题：IGF-1 + TGF-β1　；参考：《天津医科大学》2008年硕士论文

【摘要】： 本实验在成功建立碘缺乏和碘过量Wistar大鼠、Balb/c小鼠动物模型的基础上,观察不同碘摄入水平下大、小鼠的甲状腺形态及功能的变化,同时检测甲状腺组织的胰岛素样生长因子-1(IGF-1)、转化生长因子-β1(TGF-β1)的mRNA和蛋白质表达水平,进而探讨IGF-1、TGF-β1在碘缺乏和碘过量所致甲状腺生长及功能变化中的可能作用。本实验选用Wistar大鼠和Balb/c小鼠,分别随机分为3组:低碘组(LI)、正常碘组(NI)、50倍高碘组(50HI)。LI组动物饲料的平均碘含量为50μg/kg,NI组和50HI组动物饲料的平均碘含量为300μg/kg;LI组和NI组动物饮用去离子水,50HI组动物饮用加碘化钾的去离子水。根据大、小鼠每日进食量和饮水量估算各组动物每日总碘摄入量,大鼠各组分别为:1μg/d(LI组)、6μg/d(NI组)、300μg/d(50HI组),小鼠各组分别为:0.25μg/d(LI组)、1.5μg/d(NI组)、75μg/d(50HI组)。分别在饲养3、6个月后处死动物,测定尿碘、甲状腺组织碘、甲状腺组织激素、甲状腺形态学观察、形态计量学测量甲状腺球蛋白的储存及含量;同时采用实时荧光定量PCR、半定量PCR、免疫组织化学等实验技术,检测甲状腺组织IGF-1和TGF-β1的mRNA、蛋白质表达水平的变化。实验结果显示: 1尿碘和甲状腺组织碘水平:LI组大、小鼠的尿碘水平都很低,几乎测不出,NI组和50HI组的尿碘水平与其碘摄入水平基本一致;各组甲状腺组织碘含量随着碘摄入量的增加而增加,但增加的幅度远不及尿碘,与其碘摄入水平不一致。 2甲状腺组织激素水平:各时段LI组大、小鼠甲状腺组织T_3和T_4水平均明显低于同期NI组,T_3/T_4明显高于NI组;而50HI组大、小鼠之间不完全相同,表现为各时段50HI组大鼠甲状腺组织T_3含量低于同期NI组,T_4含量与NI组相比无明显差别,T_3/T_4显著降低;50HI组小鼠于3个月时,甲状腺组织T_3和T_4含量均较NI组明显增高,6个月时,T_3水平接近正常,T_4仍有所升高,但不如3个月时明显;3、6个月时T_3/T_4均较NI组有所降低,但无统计学差异。 3甲状腺形态学变化:大、小鼠NI组甲状腺滤泡均多为中等大小,上皮细胞为单层立方或扁平状,滤泡腔内胶质丰富;LI组甲状腺均呈现小滤泡增生性甲状腺肿改变;而50HI组大、小鼠则表现不同,50HI组大鼠甲状腺与NI组比较,甲状腺出现多型性变化,表现为既有部分滤泡明显增大,滤泡腔内充满浓染胶质,上皮细胞扁平,又有部分滤泡接近正常,同时增生现象明显,表现为滤泡变小,上皮细胞变为柱状,滤泡腔变小,胶质减少,提示TSH刺激征象;50HI组小鼠甲状腺与NI组比较,滤泡腔内胶质蓄积、丰满,滤泡腔增大,上皮细胞变扁平,呈现胶质蓄积性甲状腺肿,此改变与高碘大鼠不同之处在于,高碘小鼠发生了胶质蓄积性甲状腺肿,未发现甲状腺增生表现,即无明显TSH刺激征象。 4甲状腺胶质蓄积水平的形态计量学测量结果:各时段50HI组大鼠的滤泡腔截面积、大中小滤泡腔所占比率变化不明显,不提示大鼠发生大滤泡性胶质蓄积;3个月时50HI组大鼠胶质面积与视场面积比值较NI组升高,而6个月时却低于NI组,3个月时50HI组胶质平均灰度低于NI组,6个月时与NI组相比无差别,表明大鼠在高碘摄入情况下,其甲状腺球蛋白总含量变化不明显。与大鼠不同,50HI组小鼠的甲状腺滤泡腔截面积明显增大,小、中等滤泡腔明显减少,大滤泡腔明显增多,提示小鼠发生了大滤泡性胶质蓄积;50HI组小鼠的甲状腺胶质面积与视场面积比值以及胶质的平均灰度均明显高于NI组,表明小鼠在高碘摄入下甲状腺球蛋白总含量明显增加。 5大、小鼠甲状腺IGF-1和TGF-β1mRNA及其蛋白表达水平:3个月时大鼠,与NI组相比,LI组和50HI组甲状腺IGF-1mRNA表达水平均升高,其中50HI组升高更为显著(P＜0.01);6个月时大鼠,与NI组相比,LI组甲状腺IGF-1mRNA表达水平较NI组明显下降,50HI组与NI组比较无统计学差异。3个月时大鼠,与NI组相比,LI组和50HI组IGF-1蛋白表达显著增加,在甲状腺上皮细胞胞浆内可见明显的阳性颗粒;6个月时大鼠,LI组IGF-1蛋白表达显著弱于NI组,50HI组与NI相比无明显差别。各时段小鼠甲状腺IGF-1mRNA表达水平,LI组显著高于NI组,50HI组与NI组比较无统计学差异。3、6个月时小鼠,与NI组相比,LI组IGF-1蛋白表达显著增加,50HI组IGF-1蛋白表达无明显变化。结果表明,各组大、小鼠甲状腺IGF-1mRNA和蛋白表达水平基本一致。 3、6个月时大鼠,LI组和50HI组甲状腺TGF-β1mRNA表达水平均较NI组明显升高,其中LI组升高更为显著。3个月时大鼠,LI组甲状腺TGF-β1蛋白表达显著弱于NI组,50HI组与NI相比无明显差别;6个月时大鼠,与NI组相比,LI组TGF-β1蛋白表达显著增高,50HI组显著降低。3、6个月时小鼠甲状腺TGF-β1mRNA水平,LI组和50HI组均显著高于NI组。3个月时小鼠,LI组TGF-β1蛋白表达与NI相比无明显差别,50HI组显著弱于NI组;6个月时小鼠,与NI组相比,LI组TGF-β1蛋白表达显著增高,50HI组无明显差别。结果表明,只有6个月时LI组大、小鼠的甲状腺TGF-β1mRNA和蛋白质表达水平一致,3个月时LI组和各时段50HI组大、小鼠甲状腺TGF-β1mRNA和蛋白质表达水平不一致。从上述实验结果可以得出如下结论: 1碘缺乏时大、小鼠均表现为明显甲状腺功能减退,代偿性出现小滤泡增生性甲状腺肿。碘过量时,大鼠甲状腺仅发生了多型性改变,未形成甲状腺肿;而小鼠发生了典型胶质蓄积性甲状腺肿。大鼠和小鼠对碘过量均具有较强的适应能力,但它们之间在稳定甲状腺内碘含量、稳定激素水平(激素合成、转化、释放)、以及甲状腺随之发生的结构改变存在较大差异;从总体看来,大鼠比小鼠对高碘摄入具有更强的适应能力。 2本研究观察到碘缺乏时大鼠甲状腺IGF-1表达呈一过性升高,小鼠甲状腺IGF-1表达始终维持在较高水平;提示IGF-1参与了碘缺乏诱发甲状腺增生性肿大的发病过程;碘过量时大、小鼠甲状腺IGF-1表达水平变化不完全相同,但与各自发生的甲状腺形态学改变相一致。对于甲状腺自分泌的IGF-1与碘缺乏和碘过量所致甲状腺功能改变的关系尚需进一步研究和深入探讨。 3碘缺乏时,大鼠和小鼠甲状腺自分泌TGF-β1升高,抑制甲状腺滤泡细胞的增生(此时甲状腺呈增生状态),体现甲状腺器官的自稳调控机制;碘过量时,大鼠和小鼠甲状腺自分泌TGF-β1mRNA表达也升高,可能分别参与了高碘所致大鼠甲状腺呈多型性变化但无肿大形成、小鼠甲状腺胶质蓄积性甲状腺肿形成的调控过程。
[Abstract]:In this experiment, on the basis of the successful establishment of iodine deficiency and iodine excess Wistar rats and Balb/c mice model, the changes in the thyroid morphology and function of mice under different iodine intake levels were observed, and the mRNA and protein expression levels of IGF - beta 1 (TGF- beta 1) in the thyroid tissue were detected. The possible role of IGF-1 and TGF- beta 1 in the growth and function of thyroid gland induced by iodine deficiency and iodine excess was further explored.
Wistar rats and Balb/c mice were randomly divided into 3 groups: low iodine group (LI), normal iodine group (NI), 50 times high iodine group (50HI) group.LI animal feed average iodine content was 50 mu g/kg, NI and 50HI group animal feed average iodine content was 300 mu g/kg; LI group and NI group animals drinking deionized water. Ion water. According to the daily intake and drinking amount of the mice, the daily total iodine intake was estimated in each group: 1 mu g/d (group LI), 6 mu g/d (group NI), 300 mu g/d (group 50HI), respectively: 0.25 mu g/d (LI group), 1.5 micron g/d (NI group), 75 mu g/d (50HI group). Iodine, thyroid hormone, thyroid morphologic observation, morphometry were used to measure the storage and content of thyroid globulin; meanwhile, real-time fluorescence quantitative PCR, semi quantitative PCR, immunohistochemistry and other experimental techniques were used to detect the mRNA of IGF-1 and TGF- beta 1 in thyroid tissue and the changes of protein expression level.
The experimental results show that:
1 urinary iodine and iodine level of thyroid tissue: group LI was large and the level of urine iodine was very low in mice. The iodine levels in group NI and 50HI were almost the same as those of iodine intake. Iodine content in thyroid tissue in each group increased with the increase of iodine intake, but the increase was far less than that of urine iodine, which was not consistent with the iodine intake level.
2 the level of thyroid hormone: the level of LI in each time period was large and the level of T_3 and T_4 in the thyroid tissue of mice was significantly lower than that in the same period NI group. T_3/T_4 was significantly higher than that of the NI group, while the 50HI group was large and the mice were not exactly the same. The thyroid T_3 content of 50HI group was lower than that of the same stage NI group, and the T_4 content was not significantly different from that of the NI group. The levels of T_3 and T_4 in the thyroid tissue in the 50HI group were significantly higher than those in the NI group at 3 months. At 6 months, the level of T_3 was close to normal, and the T_4 was still higher, but it was not as obvious as that at 3 months. T_3/T_4 was lower in 3,6 months than in the NI group, but there was no statistical difference.
3 the morphological changes of thyroid were large, the thyroid follicles of the NI group were all medium size, the epithelial cells were single or flat, and the colloid in the follicular cavity was rich. In group LI, the thyroid gland showed small follicular hyperplastic goiter, while the group 50HI was large and the mice were different. The thyroid gland of the group 50HI rats was compared with the NI group, and the thyroid gland appeared multiple types. Sex changes, manifested as a significant increase in the follicular follicles, the follicle filled with dense staining gelatin, epithelial cells flat, and some follicles close to normal, at the same time, the proliferation phenomenon is obvious, showing that follicles become smaller, epithelial cells become columnar, follicular cavity becomes smaller, glial decrease, and TSH stimulation signs; 50HI group thyroid gland is compared with group NI, follicular The accumulation of colloid in the cavity, the enlargement of the follicle cavity, the flattening of the epithelial cells and the appearance of the glial accumulative goiter were different from those of the high iodine rats. The high iodine mice had a glial accumulative goiter, and no thyroid hyperplasia was found, that is, there was no obvious sign of TSH stimulation.
4 the results of morphometric measurement of the level of thyroid gland accumulation: the intercepting area of follicular cavity in group 50HI rats at each time period, the ratio of large and medium follicle cavity is not obvious, and the large follicular glial accumulation is not suggested in rats, and the ratio of the area to the field area of the rats in group 50HI is higher than that of the NI group at the time of 3 months, but it is lower than that of the NI group at 6 months. The average gray level of the glia in 50HI group was lower than that of the NI group at the time of 6 months, and there was no difference compared with the NI group. It showed that the total content of thyroid globulin in the rats was not significantly changed under the high iodine intake. Different from the rats, the section area of the thyroid follicle in the 50HI group was obviously increased, small, the medium follicle cavity decreased obviously, and the large follicle cavity increased obviously, suggesting that small follicle cavity increased significantly. The rats had large follicle accumulation, and the ratio of thyroid area to the field area and the average gray level of the glia were significantly higher in the 50HI group than that in the NI group, indicating that the total content of thyroid globulin in the mice was significantly increased under the high iodine intake.
5, the expression level of IGF-1 and TGF- beta 1mRNA and protein in the thyroid gland of mice: at 3 months, the expression level of IGF-1mRNA in the thyroid gland of the LI group and the 50HI group increased significantly in the LI group and the 50HI group, and the increase in the 50HI group was more significant (P < 0.01). At the time of 6 months, the expression level of the thyroid gland IGF-1mRNA in the LI group was significantly lower than that in the NI group. Compared with group NI, the expression of IGF-1 protein in LI group and 50HI group was significantly increased in group LI and 50HI, and obvious positive particles were found in the cytoplasm of thyroid epithelial cells. At 6 months, the expression of IGF-1 protein in group LI was significantly weaker than that in NI group, and there was no obvious difference between 50HI group and NI. The IGF-1mRNA expression level of thyroid gland in mice at various periods, LI The group of group 50HI was significantly higher than group NI, and there was no statistical difference between group 50HI and NI group at.3,6 months. Compared with group NI, the expression of IGF-1 protein in group LI increased significantly, and the expression of IGF-1 protein in 50HI group had no obvious change. The results showed that the thyroid IGF-1mRNA and protein expression levels were the same in each group.
In 3,6 months, the expression level of TGF- beta 1mRNA in the thyroid gland in the LI group and the 50HI group was significantly higher than that in the NI group, and the increase of the LI group was more significant at.3 months. The expression of TGF- beta 1 protein in the LI group was significantly weaker than that in the NI group, and there was no significant difference between the 50HI group and the 50HI group. At 6 months, the expression of the beta 1 protein in the group was significantly higher than that in the group. The level of TGF- beta 1mRNA in the thyroid gland of mice was significantly reduced at.3,6 months. The LI and 50HI groups were significantly higher than those in the NI group at.3 months. The TGF- beta 1 protein expression in LI group was not significantly different from NI, and the 50HI group was significantly weaker than the NI group. At 6 months, the expression of beta 1 protein in the mice was significantly higher than that in the group. The results showed that there was no significant difference between the group and the group. The results showed that only 6 In group LI, the expression level of TGF- beta 1mRNA and protein in mice was the same at the same month. At 3 months, the LI group and 50HI group were large, and the level of TGF- beta 1mRNA and protein expression in the thyroid gland of mice was not consistent.
From the above experimental results, we can draw the following conclusions:
At the time of 1 iodine deficiency, all mice showed obvious hypothyroidism and compensatory form of small follicular hyperplastic goiter. When iodine excess, the thyroid gland had only a variety of changes and did not form goiter, and the mice had a typical glial goiter. Both rats and mice had strong adaptability to iodine excess. However, there are significant differences in the iodine content in the thyroid gland, the level of stable hormone (hormone synthesis, transformation, release), and the structural changes of the thyroid gland. In general, the rats have a stronger adaptability than the mice.
2 this study observed that the thyroid IGF-1 expression in the rat thyroid gland was elevated in a hyperactivity, and the expression of IGF-1 in the thyroid gland was maintained at a high level in mice. It suggested that IGF-1 was involved in the pathogenesis of hyperthyroid enlargement induced by iodine deficiency. When iodine excess was excessive, the expression of IGF-1 in the thyroid gland of mice was not exactly the same, but it was the same as that of the thyroid gland. The morphological changes in the glands of the thyroid gland are consistent. The relationship between thyroid autocrine IGF-1 and thyroid function changes caused by iodine deficiency and iodine excess need further study and in-depth study.
In 3 iodine deficiency, the thyroid autocrine TGF- beta 1 increased in rats and mice, inhibited the proliferation of thyroid follicle cells (at this time the thyroid hyperplasia state), and reflected the autocrat regulation mechanism of thyroid organs. When iodine excess, the expression of the thyroid autocrine TGF- beta 1mRNA in rats and mice increased, which may be involved in the thyroid gland of rats induced by high iodine, respectively. The regulation process of mouse thyroid goiter accumulating goiter was caused by polymorphic change but no enlargement.
【学位授予单位】：天津医科大学
【学位级别】：硕士
【学位授予年份】：2008
【分类号】：R363

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