天津医药

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甲状腺素对甲状腺功能减低大鼠子代脑组织中同源盒基因Nkx2.2表达的影响

赵金超1,张瑞2,汪蓓蕾2,3,郭刚3   

  1. 1. 天津医科大学内分泌研究所
    2.
    3. 天津医科大学
  • 收稿日期:2010-10-09 修回日期:2011-02-24 出版日期:2011-06-15 发布日期:2011-06-15
  • 通讯作者: 赵金超

Effects of thyroxine on the expression of homeobox gene Nkx2.2 in the cerebrum tissue of the offspring of hypothyroidism pregnant rat

  • Received:2010-10-09 Revised:2011-02-24 Published:2011-06-15 Online:2011-06-15

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摘要： 【摘要】目的 通过对妊娠期甲状腺功能减低（甲低）大鼠补充甲状腺素，探讨妊娠不同时间补充不同剂量甲状腺素对子代大鼠脑组织中同源盒基因Nkx2.2表达的影响。方法 1月龄Wistar大鼠240只，雌雄各半，体质量100 ～ 120 g。按体质量将雌性大鼠随机分为8组：对照组，甲低组，甲低孕鼠妊娠早期（1 ～ 17 d）补充甲状腺素（妊早甲低）高、中、低剂量组，甲低孕鼠妊娠晚期（18 ～ 20 d）补充甲状腺素（妊晚甲低）高、中、低剂量组，每组15只。8组大鼠均饲以重度缺碘地区粮食配制的饲料，对照组饮用含碘200μg /L的碘酸钾溶液水，总碘摄人量相当于大鼠生理碘需要量，7个甲低组饮用去离子水。雄性大鼠用正常食料饲养，3个月后按1∶1交配。记录怀孕时间，8组大鼠分别取孕17 d、新生、生后20 d子代大鼠后脑组织，采用实时荧光定量(RT)PCR法检测脑组织中Nkx2.2 mRNA表达。结果 ①在孕17天、新生、和生后20天，Nkx2.2的表达组间比较差异有统计学意义（F值分别为7.080、19.007、24.652，P均﹤0.01）②组内不同时间比较差异有统计学意义（F值分别为17.633、13.163、224.942、15.182、38.371、12.240、7.048、39.038，P均﹤0.01）③时间因素和剂量因素对Nkx2.2的表达有影响（F值分别为6.992、5.939，P均﹤0.01）④时间因素和剂量因素之间有交互作用（F值为5.610，P﹤0.01）⑤Nkx2.2基因在正常组的表达从平均趋势上看，随年龄增长而逐渐上升；低碘组各时期均高于同时期正常组的表达水平（P﹤0.05）； ⑥晚期中剂量给药组在新生期、生后20天与正常组同时期的水平接近（P﹥0.05）结论 甲低孕鼠子代大鼠脑组织同源盒基因Nkx2.2的表达受补充甲状腺素剂量及时间影响。

关键词: 甲状腺功能减低, 同源盒基因, 实时荧光定量PCR

Abstract: 【Abstract】Objective To explore the effects of thyroid hormone on the expression of homeobox gene Nkx2.2 in child rat and the relationship between gene expression and hormone level by supplying their hypothyroidism pregnant mother with thyroid hormone. Method 240 Wistar rats,half male and half female, were randomly divided into eight groups: normal control group,hypothyroidism group, hypothyrodism groups which were supplied with thyroid hormone in different doses in early stage(1-17d),hypothyrodism groups which were supplied with thyroid hormone in different doses in late stage(18-20d) .All the rats were fed with low-iodine food.The normal control group was given KIO3 solution and the other groups were given deionized water.After three months’raising,each group was drawn materials from the 17-day fetal rats,new-born and 20-day old offspring,and was detected the content of Nkx2.2 mRNA in afterbrain tissue by real-time fluorescence quantitative PCR techniques. Results① The expression of Nkx2.2 mRNA have significant difference between groups in 17-day fetal rats,new-born and 20-day old offsprings(F=7.080、19.007、24.652，P﹤0.01）②The time factor and dosage factor have influence on Nkx6.1 mRNA expression (F=6.992、5.939，P﹤0.01) ③Time factor and dosage factor have interaction（F=5.610，P﹤0.01）④ the expression level in low-iodine group were higher than normal group during the same period（P﹤0.05）,and it increased gradually with age.⑤ The expression of Nkx2.2 mRNA in new-born and 20-day old offsprings which were supplied with thyroid hormone in high and medium dosage in late stage is close to the normal group at the same period（P﹥0.05）.Conclusion The expression of Nkx2.2 in child rats is highly related to the supply dosage and supply time of thyroid hormone in hypothyrodism preganant rats.

Key words: Hypothyroidism, Homeobox gene, Real-time fluorescence quantitative PCR