摘要
目的 探讨不同程度碘缺乏引起的母亲甲状腺功能异常对胎儿脑发育标志物双皮质素（DCX）、突触素p38基因表达的影响.方法 Wistar雌鼠按每日总碘供给量（自来水中添加不同浓度的KI,食用低碘饲料）分为碘适宜组（AI）、轻度缺碘组（MiID）、中度缺碘组（MoID）、重度缺碘组（SID）.喂养3个月后交配,检测妊娠20天母鼠尿碘、甲状腺组织学、血清TSH和甲状腺激素（TH）水平,胎脑DCX和突触素p38 mRNA和蛋白表达水平.结果 （1）碘缺乏组母鼠尿碘随饮食碘供给量的减少而降低.与AI组比较,SID组孕鼠血清TSH水平升高[（2.95±1.70对1.31 ±0.55）mIU/L,P＜0.05],TT4[（14.3±4.1对28.4±19.3）nmol/L,P＜0.05]和FT4[（10.8±3.6对20.2±8.0）pmol/L,P＜0.01]降低；MoID、MiID组TSH水平呈升高趋势,TT4和FT4呈降低趋势；TT3、FT3水平各组差别无统计学意义.（2）SID组甲状腺呈现典型的小滤泡增生性甲状腺肿改变、胶质缺如；MoID组呈中度小滤泡增生性变化、胶质减少；MiID组仅呈轻度细胞增殖,但滤泡大小与AI组相似、胶质减少不明显.（3）与AI组比较,各缺碘组胎脑DCX mRNA表达呈升高趋势,MoID组升高有统计学意义（P＜0.01）,蛋白表达在各碘缺乏组均明显上调（P＜0.01）；而突触素p38 mRNA和蛋白表达在各碘缺乏组均显著下调（P＜0.01）.结论 母亲碘缺乏使胎儿脑神经元发育和突触生长受到损伤,其损伤随母亲的缺碘程度而逐渐加重；尤其母亲轻、中度碘缺乏就能明显抑制胎儿脑发育应引起关注.
Objective To investigate the effects of maternal thyroid dysfunction during pregnancy caused by iodine deficiency of different degrees on doublecortin （ DCX ） and synaptophysin （ p38 ） expressions in fetal brain.Methods Wistar female rats were randomly divided into four groups：adequate iodine （ AI）,mild iodine deficiency （ MiID ）,moderate iodine deficiency （ MoID ）,and severe iodine deficiency （ SID ）,according to the total daily iodine supply（ fed on an iodine deficient diet with different dosages of KI added in drinking water）.Three months later the rats were mated.Serum TSH and thyroid hormones were determined in maternal rats on gestational day 20 using chemiluminescent immunoassay.The iodine contents in urine and histological changes of thyroid gland were observed in pregnant rats.The mRNA and protein levels of DCX and synaptophysin （ p38 ） were analyzed in fetal brain by using real time quantitative RT-PCR and western blotting respectively.Results （ 1 ） Iodine contents in urine of pregnant rats were reduced with the decrease of their iodine supply.Compared with group AI,serum TSH was significantly increased [ （ 2.95 ± 1.70 vs 1.31 ± 0.55 ） mU/L,P 〈 0.05 ],and both TT4 and FT4 were significantly decreased [ （ 14.3±4.1 vs 28.4±19.3 ） nmol/L,P〈0.05 ] and [ （ 10.8±3.6 vs 20.2±8.0） pmol/L,P〈0.01 ] in pregnant rats of SID group.Whereas,a slight rise in TSH,and a mild decline in both TT4and FT4 were found in MoID and MiID groups.However,there were no significant changes in TT3 and FT3 levels among these four groups.（ 2 ）Histological characteristics of thyroid gland in pregnant rats showed a typical goiter with small follicular hyperplasia and lack of colloid in SID group,moderate follicular hyperplasia with decreased colloid in MoID group; but mild cellular hyperplasia without decrease in follicular size and colloid in MiID group.（ 3 ） The mRNA levels of DCX were increased in fetal brains of three iodine deficiency groups compared with AI group,but a statistical significance was found in MoID group.The protein levels of DCX in all experiment groups were significantly increased.Both mRNA and protein expressions of synaptophysin （ p38 ） were significantly down-regulated in three iodine deficiency groups.Conclusions Maternal thyroid dysfunction caused by iodine deficiency,even by mild or moderate iodine deficiency,may lead to retardation of fetal neuronal and synaptic growth.
出处
《中华内分泌代谢杂志》
CAS
CSCD
北大核心
2012年第2期146-149,共4页
Chinese Journal of Endocrinology and Metabolism
基金
国家自然科学基金（30901460,30671816）
关键词
碘缺乏
妊娠期
甲状腺功能
双皮质素
突触素
Iodine deficiency
Pregnancy
Thyroid function
Doublecortin
Synaptophysin
