妊娠大鼠碘缺乏和甲状腺功能减退对仔鼠内嗅皮质神经颗粒素表达的影响

Effects of Iodine Deficiency and Hypothyroidism during Pregnancy on the Protein Expressions of Neurogranin in the Entorhinal Cortex of Pups

目的研究碘缺乏和甲状腺功能减退损伤内嗅皮质对神经颗粒素(neurogranin,Ng/RC3)表达的影响。方法将28只妊娠清洁级Wistar大鼠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PN7、PN14、PN21、PN28和PN42时,每组随机取5只仔鼠,观察内嗅皮质Ng的表达。结果 PN7时,各组仔鼠内嗅皮质Ng表达水平间比较,差异无统计学意义。PN14时,甲状腺功能减退2组和碘缺乏组仔鼠内嗅皮质Ng表达水平低于对照组和甲状腺功能减退1组,差异均有统计学意义(P<0.05)。PN21,PN28和PN42时,甲状腺功能减退2组和碘缺乏组仔鼠内嗅皮质Ng表达水平低于对照组,差异均有统计学意义(P<0.05);PN42时,甲状腺功能减退1组仔鼠内嗅皮质Ng表达水平亦低于对照组,差异有统计学意义(P<0.05)。与对照组比较,甲状腺功能减退1、2组和碘缺乏组内嗅皮质Ng染色强度明显降低。结论妊娠大鼠碘缺乏和甲状腺功能减退可降低仔鼠内嗅皮质Ng的表达。

Objective To observe the effect of iodine deficiency and hypothyroidism on the protein expressions of neurogranin （Ng） in the entorhinal cortex of pups. Methods Twenty-eight Female Wistar clean rats after pregnancy were randomly divided into control group, hypothyroid t and 2 group and iodine-deficient group （ 7 in each group）. From GD6 till PN28, iodinedeficient group was administered with iodine-deficient diet [iodine content： （14.11±1.96） ng/g] and tap water; Hypothyroid 1 and 2 group were administered with 5 mg/L and 15 mg/L propyhhiouracil （PTU） in the drinking water and fed with normal diet [iodine content： （470.50±46.52） ng/g]. Control group received tap water and normal diet during the experiment. Five pups from each group were sacrificed and intracardiac perfused at PNT,PN14,PN21,PN28 and PN42. Brains were removed,fixed and sectioned coronally. All sections were observed and analyzed for the expression of Ng by immunohistochemistry in the entorhinal cortex. Results At PNT, there was no significantly difference in the expression of Ng in all four groups. At PN 14, the expression of Ng at the entorhinal cortex in iodine-deficlent and hypothyroid 2 groups were significantly lower than those of control and hypothyroid 1 groups （P〈0.05）. At PN21,PN28 and PN42,the iodine deficiency and 15 mg/L PTU-treatment significantly reduced Ng in the entorhinal cortex （P〈0.05）. At PN42, the expression of Ng in the entorhinal cortex in hypothyroid 1, 2 group and iodine-deficient groups were significantly lower than that of control （P〈0.05）. Conclusion Iodine deficiency and hypothyroidism during pregnancy may decrease the expression of Ng in the entorhinal cortex of pups.