摘要
目的研究妊娠期大鼠不同程度碘缺乏对胎鼠碘代谢和甲状腺功能的影响。方法40只Wistar雌性大鼠按体质量随机分为4组，每组10只，均食用低碘饲料（含碘量为50μg／kg）；重、中、轻度缺碘（SID、MoID、MiID）组和正常碘（NI）组饮用含不同剂量碘化钾（0、54．9、163．8、381．7μg/L）的自来水（含碘量为8μg／L），每日总碘供给量分别为1．24、2．50、5．00、10．00μg。喂养3月后与按NI组条件饲养的Wistar雄性鼠交配，以妊娠20d孕鼠和胎鼠为研究对象，过硫酸铵消化砷铈催化分光光度法测定孕鼠尿碘和胎鼠羊水含碘量，碱灰化砷铈催化分光光度法测定孕鼠血碘和胎盘组织含碘量，化学发光法测定孕鼠血清及胎鼠羊水甲状腺激素水平，检测并观察孕鼠和胎鼠的甲状腺质量及大体变化。结果①孕鼠尿碘、血碘，胎鼠羊水碘均随碘供给量减少呈降低趋势。NI、MiID、MoID、SID组孕鼠尿碘中位数分别为353．7、115．9、26．9、0μg／L，组间比较差异有统计学意义（X2=32．884，P〈0．01）；MoID、SID组[（29．4±18．6）、（11．7±7．0）μg／L]孕鼠血碘明显低于NI组[（49．1±23．0）μg／L，P〈0．05或〈0．01）。与NI组[（65．4±41．2）μg／L，（0．35±0．14）μg／g]比较，Mlid、MoID、SID组胎鼠羊水碘[（48．3±23．1）、（29．2±14．7）、（19．5±6．7）μg／L]呈降低趋势，胎盘组织碘[（0．57±0．26）、（0．53±0．34）、（O．53±0．15）μg／g]呈升高趋势，但组间比较差异均无统计学意义（P〉0．05）。②SID组孕鼠血清TT4[（14．3±4．1）nmol／L]和FT4[（10．8±3．6）pmol／L]明显低于NI组[（28．4±19．3）nmol／L，（20．2±8．0）pmol／L，P〈0．05或〈0．01]，而FT3／FT4比值（0．34±0．16），甲状腺绝对质量[（48．4±22．7）mg]和相对质量[（144±76）mg／kg]明最高于NI组[（0．16±0．02）、（19．5±3．1）mg，（66±10）mg／kg，P〈0．01]；MiID、MoID组‘ITr4[（25．5±13．1）、（22．1±6．1）nmol／L]和FT4[（18．6±8．4）、（18．5±4．1）pmol／L]与NI组比较，有降低趋势，FT3／FT4比值（0．17±0．06、0．19±0．04），甲状腺绝对质量[（25．0±8．9）、（27．0±5．7）mg]和相对质量[（78±25）、（84±19）mg／kg]与NI组比较，有增高趋势，但组间比较差异均无统计学意义（P〉0．05）；SID组孕鼠甲状腺明显充血肿大，Mild、MoID组轻度肿大。⑧SID组胎鼠羊水吼[（1．07±0．87）pmol／L]低于NI组[（2．38±1．55）pmol／L]，FT3／FT4比值（1．96±0．61）高于NI组（0．50±0．18），组间比较差异均有统计学意义（P〈0．05或〈0．01）；MliD、MoID组FT4[（2．77±0．90）、（2．35±0．76）pmol／L】、FT3／FT4比值（0．46±0．15、0．61±0．21）与NI组比较，差异均无统计学意义（P〉0．05）；SID组胎鼠甲状腺有明显充血肿大，MiID、MoID组仅见轻度充血，其大小与NI组相似。结论重度碘缺乏使孕鼠及其胎鼠均发生了明显甲状腺功能减退症，而轻度碘缺乏通过代偿可使胎儿甲状腺激素维持正常水平，中度碘缺乏对母亲和胎儿均有不同程度的负面影响。
Objective To study the effects of iodine deficiency during pregnancy on fetal iodine metabolism and thyroid function. Methods Wistar dams were randomly divided into four groups： severe iodine deficiency（SID）, moderate iodine deficiency（MoID）, mild iodine deficiency（MilD） and normal iodine（NI）. All the dams were fed with iodine deficient food （iodine contents： 50 μg/kg） and drinking water with different doses of KI （0,54.9,163.8,381.7 μg/L） for 3 months till mating. Iodine was supplied at the dose of 1.24 μg/d（SID）, 2.50 μg/d（MoID）, 5.00 μg/d（MiID） and 10.00 μg/d（NI）, respectively. The dams and their fetuses on gestation of 20 days were studied. Urine iodine of dams and iodine contents in fetal amniotie fluid were measured by As3±-Ce4± catalytic spcetrophotometry using ammonium persuffate digestion. And blood iodine in pregnant rats and iodine contents in placental tissue were measured by As3±-Ce4± catalytic spectrophotometry in dry ash of samples in KClO3- ZnSO4-K2CO3-NaCl. Thyroid hormone levels in mother serum and in fetal amniotie fluid were detected by chemiluminascent assay, and their thyroid glands were weighted and carefully observed. Results （1）Iodine content in urine and blood of pregnant rats and amniotic fluid of fetal rats reduced along with their decrease of iodine supply. Urine iodine median of rats in 4 groups（NI： 353.7 μg/L; MiID： 115.9μg/L; MoID： 26.9 μg/L; SID： 0 μg/L） were statistically significant （X2 = 32.884, P 〈 0.01 ）. Blood iodine level in MoID and SID[ （29.4 _± 18.6）, （11.7 ± 7.0）μg/L] was significantly lower than that in NI[（49.1 ± 23.0））μg/L, P 〈 0.05 or 〈 0.01 ]. In iodine deficiency groups, there was a decreasing trend in iodine contents of fetal amniotie fluid[MiID： （48.3 ± 23.1）μg/L; MoID： （29.2 ± 14.7）μg/L; SID： （19.5 ± 6.7）μg/L] and an increasing tendency in iodine contents of placental tissue [MilD： （0.57 ± 0.26）μg/g, MoID： （0.53 ± 0.34）μg/g; SID： （0.53 ± 0.15）μg/g], but there was no statistical signifieance（P 〉 0.05）. （2）In SID, TT4[ （14.3 ± 4.1 ）nmol/L] and FT4[ （10.8 ± 3.6）pmol/L] were lower than that in NI[（28.4 ± 19.3）nmol/L, （20.2 ± 8.0）pmol/L, P 〈 0.05 or 〈 0.01], while that in MoID[（22.1 ± 6.1）nmol/L, （18.5 ± 4.1 ）pmol/L] and MiID[ （25.5 ± 13.1）nmol/L, （18.6 ± 8.4）pmol/L] were decreased Without statistical significance （P 〉 0.05 ）. And FT3/FT4 ratio （0.34 ± 0.16）, absolute [ （48.4 ± 22.7）mg I and relative weights [ （ 144 ± 76）mg/kg] of thyroid gland in pregnant rats were respectively higher than that in NI[0.16 ± 0.02, （19.5 ± 3.1 ）mg, （66 ± 10）mg/kg, P 〈 0.01 ]. But that in MoID[0.19 ± 0.04, （27.0 ± 5.7）mg, （84 ± 19）mg/kg] and MiID[0.17 ± 0.06, （25.0 ± 8.9）mg, （78 ± 25）mg/kg] were increased without statistical signifieance（P 〉 0.05）. A visibly congestive enlargement thyroid was found in SID, while thyroid mildly enlarged in MoID and MiID. （3）Compared with NI [（2.38 ± 1.55）pmol/L,0.50 ± 0.18], the FT4 levels [ （1.07 ± 0.87）pmol/L] in amniotie fluid were significantly deereased（P 〈 0.05） and the FT3/FT4 ratio（1.96 ± 0.61） was significantly increased（P 〈 0.01 ） in SID. There were no statistical significanees（P 〉 0.05） in other 3 groups[MiID： （2.77 ± 0.90）pmol/L,0.46 ± 0.15; MoID： （2.35 ± 0.76）pmol/L,0.61 ± 0.21]. A visible thyroid enlargement with hyperemia was observed in SID fetus while in other 2 experiment groups their thyroids were only mildly congested. Conclusions Severe iodine deficiency during pregnancy can result in both mother and fetus overt hypothyroidism. The fetal thyroid hormone levels in mild iodine deficiency status is close to normal levels because of maternal and placental compensation. Moreover, both the dam and the fetus suffer from the negative effects in moderate iodine deficiency during pregnancy.
出处
《中国地方病学杂志》
CAS
CSCD
北大核心
2009年第3期244-248,共5页
Chinese Jouranl of Endemiology
基金
基金项目：国家自然科学基金（30671816）
关键词
妊娠
碘
缺乏症
甲状腺肿
Pregnancy
Iodine
Deficiency diseases
Goiter
