妊娠大鼠碘缺乏和甲状腺功能减退对仔鼠海马神经颗粒素表达的影响

Effects of Iodine Deficiency and Hypothyroidism in Pregnant Rats on Protein Expressions of Neurogranin in Hippocampus of Offspring

目的观察妊娠大鼠碘缺乏和甲状腺功能减退对仔鼠海马神经颗粒素(neurogranin,Ng/RC3)表达的影响。方法将妊娠清洁级Wistar大鼠28只按体重随机分成对照组、碘缺乏组、甲状腺功能减退1、2组,每组7只。自妊娠第6天(GD6)起,碘缺乏组饲以缺碘地区粮食配制的饲料[碘含量为(14.11±1.96)ng/g],饮用自来水;甲状腺功能减退1、2组分别给予5和15mg/L丙基硫尿嘧啶(propylthiouracil,PTU)溶液作为饮用水,饲喂普通饲料[碘含量为(470.50±46.52)ng/g],直至仔鼠出生后第28天(PN28);对照组饮用自来水,饲喂普通饲料。分别于PN14、PN21、PN28和PN42时,每组随机取5只仔鼠,观察海马CA1、CA3和DG区Ng表达。结果在PN14时,碘缺乏组、甲状腺功能减退1、2组仔鼠海马CA1区Ng蛋白表达水平低于对照组,差异均有统计学意义(P<0.05);在PN21时,碘缺乏组、甲状腺功能减退1、2组仔鼠海马CA1区以及碘缺乏组、甲状腺功能减退2组仔鼠海马CA3区Ng蛋白表达水平低于对照组,差异均有统计学意义(P<0.05);在PN28时,碘缺乏组、甲状腺功能减退1、2组仔鼠海马CA3区以及碘缺乏组、甲状腺功能减退2组仔鼠海马CA1区Ng蛋白表达水平低于对照组,差异均有统计学意义(P<0.05);在PN42时,碘缺乏组、甲状腺功能减退1、2组仔鼠海马CA3区和CA1区Ng蛋白表达水平低于对照组,差异均有统计学意义(P<0.05)。结论妊娠大鼠碘缺乏和甲状腺功能减退可降低仔鼠海马CA1和CA3区Ng的表达。

Objective To study the effect of iodine deficiency and hypothyroidism in pregnant rats on the protein expressions of neurogranin （Ng/RC3） in the hippocampus of pups. Methods The pregnant Wistar rats （n=28） were randomly divided into control group,hypothyroid 1, 2 group and iodine deficient group （ 7 in each group）. From GD6 till PN28, iodine-deficient group was administered with iodine-deficient diet [iodine content： （14.11 ± 1.96） ng/g ]and tap water; hypothyroid 1 and 2 groups were administered 5 mg/L and 15 mg/L PTU in the drinking water and were fed with normal diet [iodine content： （470.50±46.52） ng/g]. Control group received tap water and normal diet during the study. Five offspring from each group were sacrificed on PN14, PN21, PN28 and PN42, and the brain slices were prepared for the detection of the protein expression of Ng by immunohistochemistry in the CA1,CA3 and DG regions of hippocampus. Results On PN14, the expression of Ng in the CA1 region of hippocampus in hypothyroid 1 group, hypothyroid 2 group and iodine deficient group were significantly lower than those of the control （P〈0.05）. On PN21, the expression of Ng in the CA1 region of hippocampus in hypothyroid 1 group, hypothyroid 2 group and iOdine deficient group and in the CA3 region of hippocampus in hypothyroid 2 group and iodine deficient group were significantly lower than those of the control （P〈0.05）. On PN28, the expression of Ng in the CA3 region of hippocampus in hypothyroid 1 group, hypothyroid 2 group and iodine deficient group and in the CA1 region of hippocampus in hypothyroid 2 group and iodine deficient group were significantly lower than those of controls （P〈0.05）. On PN42, the expression of Ng in CA1 and CA3 regions of the hippoeampus in hypothyroid 1 group, hypothyroid 2 group and iodine deficient group were significantly lower than those of the control （P〈0.05）. Conclusion Iodine deficiency and hypothyroidism during pregnancy may decrease the protein expression of Ng in CA 1 and CA3 regions in the hippocampus of offspring.