不同碘摄入量对子二代小鼠生长、脑发育的影响

发布时间：2018-06-28 13:43

本文选题：碘缺乏 + 碘过量　；参考：《天津医科大学》2008年硕士论文

【摘要】： 目的: 研究不同碘摄入量对20日龄、40日龄子二代Balb/c小鼠生长发育的影响及大脑、小脑皮质和海马的形态学改变,进一步探讨碘缺乏和碘过量对子二代小鼠生长发育、大脑、小脑发育及功能的影响。方法: 选用断乳后一个月,体重在16～20 g的SPF-VAF级的Balb/c小鼠,雌雄各半,随机分为5组:低碘组(LI)、适碘组(NI)、5倍碘组(5HI)、10倍碘组(10HI)、50倍碘组(50HI),LI组动物饲以低碘饲料(平均碘含量＜50μg/kg),其余各组饲以正常饲料(平均碘含量300μg/kg),上述两种饲料中各种粮食的配比相同,只是碘含量不同。LI组饮用去离子水,其余各组饮用含不同浓度碘化钾的去离子水,其饮水中碘化钾含量分别为10μg/L(NI),1200μg/L(5HI),2700μg/L(10HI),14700μg/L(50HI)。小鼠每日的碘摄入量估计如下:小鼠每日进食5g,进水5ml,各组动物每日碘摄入量分别为:＜1μg/d(LI),1.5μg/d(NI),7.5μg/d(5HI),15μg/d(10HI),75μg/d(50HI)。喂养三个月后,雌雄随机1:1合笼,连续传两代,分别取20日龄、40日龄子二代小鼠脑组织,电子天平称重,中性福尔马林溶液固定后常规石蜡包埋,进行焦油紫染色、免疫组化(NSE、GFAP、MBP)染色,观察大脑皮质,海马区神经元、星形胶质细胞及少突胶质细胞形态学的改变。应用Motic Images Advanced 3.1图像分析系统测量以下指标:焦油紫染色切片中大脑皮质分子层厚度;免疫组化切片中海马CA3区NSE阳性神经元面数密度、平均光密度;CA1区GFAP阳性星形胶质细胞面数密度、平均光密度及MBP阳性少突胶质细胞平均光密度。小脑NSE阳性神经元和GFAP阳性星形胶质细胞的面数密度(N_A)、体积密度(V_V)、细胞质的平均光密度,MBP阳性神经纤维平均光密度,小脑皮质分子层及颗粒层厚度。结果: 1子二代小鼠生长发育:20日龄时,LI组和50HI组子二代小鼠的体重、脑重和身长、尾长、后肢长与NI组相比呈现出了不同程度的发育落后,其中LI组表现更为明显。40日龄时小鼠体格有所增长,但与NI组比较,LI组和50HI组仍呈现不同程度的发育落后。 2子二代小鼠大脑皮质、海马发育:与NI组相比,20日龄、40日龄子二代小鼠其余各组均表现出不同程度的脑发育差别,其中LI组、50HI组落后更为明显,且差异有统计学意义。 3子二代小鼠小脑皮质、颗粒层,髓质发育:与NI组相比,20日龄、40日龄子二代小鼠其余各组小脑GFAP、NSE、MBP及皮质层、颗粒层厚度均降低,其中LI组、50HI组落后更为明显,且差异有统计学意义。结论: 1子二代小鼠生长发育:碘缺乏和严重碘过量都会影响子二代小鼠的生长发育,其中碘缺乏的影响更为明显,其机理可能与碘缺乏和碘过量所致甲状腺功能低下有关。 2子二代小鼠大、小脑皮质、海马发育:脑发育临界期碘缺乏和严重碘过量都会影响子二代小鼠大脑皮质发育,海马区及小脑神经元、神经胶质细胞的酶和蛋白的合成和代谢。
[Abstract]:Objective: to study the effects of different iodine intake on the growth and development of the second generation Balb / c mice at the age of 20 and 40 days and the morphological changes in the cerebellum, cerebellar cortex and hippocampus. To further investigate the effects of iodine deficiency and iodine excess on the growth, development and function of the second generation mice. Methods: one month after weaning, Balb / c mice of SPF-VAF grade, weighing 1620 g, were divided into two groups, half male and half female. They were randomly divided into five groups: low iodine group (Li), high iodine group (NI), 5 times iodine group (5 HI), 10 times iodine group (10 HI), 50 times iodine group (50 HI) and 50 times iodine group (average iodine content < 50 渭 g/kg). The rest groups were fed with normal diet (average iodine content 300 渭 g/kg). The proportion of grain is the same. Only the deionized water with different iodine content. The other groups drank deionized water with different concentrations of potassium iodide, and the drinking water contained 10 渭 g / L (NI) 1200 渭 g / L (5HI) of 2700 渭 g / L (10HI) 14700 渭 g / L (50HI) of potassium iodide. The daily iodine intake of mice was estimated as follows: the daily iodine intake of mice was less than 1 渭 g / d (Li), 1.5 渭 g / d (NI), 7.5 渭 g / d (5HI), 15 渭 g / d (10 HI) and 75 渭 g / d (50HI), respectively. After feeding for three months, the male and female were randomly caged at 1:1 for two consecutive generations. The brain tissues of the second generation mice of 20 days old or 40 days old were weighed by electronic balance, fixed with neutral formalin solution and routinely embedded in paraffin, and then stained with tar violet. The morphological changes of neurons, astrocytes and oligodendrocytes in the cerebral cortex, hippocampus and astrocytes were observed by immunohistochemical staining (NSE-GFAP MBP). The following indexes were measured by using the image analysis system of Motic Images Advanced 3.1: the thickness of cerebral cortex molecular layer in tar violet staining section and the number density of NSE-positive neurons in hippocampal CA3 area in immunohistochemical section. The number density of GFAP positive astrocytes, the average optical density and the average optical density of MBP positive oligodendrocytes in CA1 region were observed. The surface number density (NA), volume density (VV), mean optical density of MBP positive nerve fibers and the thickness of molecular layer and granular layer of cerebellar cortex were observed in cerebellar NSE positive neurons and GFAP positive astrocytes. Results: 1 the body weight, brain weight and body length, tail length, hind limb length of the second generation mice of the second generation of mice at the age of 20 days were lower than those of the NI group, and the mice in the second generation group showed different degrees of developmental backwardness compared with the NI group. The physique of Li group was more obvious than that of NI group at 40 days old, but compared with NI group, Li group and 50HI group still showed different degrees of developmental backwardness. Hippocampal development: compared with NI group, the other groups showed different degrees of brain development, especially in Li group. And the difference was statistically significant. The development of cerebellar cortex, granular layer and medulla: compared with NI group, the thickness of granular layer in cerebellar GFAPN NSEMBP and cortical layer of other groups were decreased compared with NI group. Li group was more backward than 50 HI group, and the difference was statistically significant. Conclusion: 1 the growth and development of the second generation mice: both iodine deficiency and severe iodine excess will affect the growth and development of the second generation mice, and the effect of iodine deficiency is more obvious. The mechanism may be related to hypothyroidism induced by iodine deficiency and iodine excess. Hippocampal development: iodine deficiency and severe iodine excess in the critical stage of brain development can affect the synthesis and metabolism of enzymes and proteins in the cerebral cortex, hippocampal and cerebellar neurons and glial cells of the second generation mice.
【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

【相似文献】