妊娠大鼠碘缺乏和甲状腺功能减退对仔鼠内嗅皮质cAMP反应元件结合蛋白表达的影响

Effects of Iodine Deficiency and Hypothyroidism during Pregnancy on the Protein Expressions of cAMP Response Element-Binding Protein in the Entorhinal Cortex of Pups

目的观察碘缺乏和甲状腺功能减退损伤内嗅皮质对cAMP反应元件结合蛋白(cAMP response element-binding protein,CREB)蛋白表达的影响。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CREB的表达。结果 PN7时,各组仔鼠内嗅皮质CREB表达水平间比较,差异无统计学意义。PN14和PN21时,甲状腺功能减退1组、2组和碘缺乏组仔鼠内嗅皮质CREB表达水平低于对照组,差异均有统计学意义(P<0.05)。PN14时,甲状腺功能减退2组和碘缺乏组CREB表达水平低于甲状腺功能减退1组,差异均有统计学意义(P<0.05)。PN28和PN42时,甲状腺功能减退2组和碘缺乏组仔鼠内嗅皮质CREB表达水平低于对照组,差异均有统计学意义(P<0.05);PN28时,碘缺乏组仔鼠内嗅皮质CREB表达水平低于甲状腺功能减退1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CREB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CREB表达。

Objective To observe the effect of iodine deficiency and hypothyroidism on the protein expressions of CREB in the entorhinal cortex of pups. Methods Twenty-eight female Wistar clean rats after pregnancy 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 group were administered with 5 mg/L and 15 mg/L PTU in the drinking water and fed with normal diet [iodine content： （470.50±16.52） ng/g]. Control group received tap water and normal diet during the experiment. Five pups from each group were sacrificed and intraeardiae perfused at PN7,PN14,PN21, PN28 and PN42. Brains were removed,fixed and sectioned eoronally. All sections were observed and were analyzed for the protein expression of CREB by immunohistochemistry in the entorhinal cortex. Results At PN7 ,there was no significant difference in the expression of Ng in all four groups. At PN14 and PN21 ,the expression of CREB in the entorhinal cortex in hypothyroid 1, 2 group and iodine deficient group were significantly lower than those of controls （P〈0.05）. At PN14, the expression of CREB in the entorhinal cortex in hypothyroid 2 group and iodine deficient group were significantly lower than those of hypothyroid 1 group （P〈0.05）. At PN28 and PN42, the expression of CREB in the entorhinal cortex in iodine-deficient group and hypothyroid 2 group were significantly lower than those of control （P〈0.05）. At PN28, the expression of CREB in the entorhinal cortex in iodine-deficient group was significantly lower than those of hypothyroid 1 group （P〈0.05）. Conclusion Iodine deficiency and hypothyroidism during pregnancy may decrease the protein expression of CREB in the entorhinal cortex of pups.