摘要目的 观察不同碘营养水平下大鼠妊娠期碘代谢水平的变化情况.方法 雌性Wistar大鼠150只,体质量80～100 g,按体质量分层后随机分为5组:对照组(NI),低碘1、2组(LI1、LI2),高碘1、2组(HI1、HI2),每组30只.分别饮用含碘离子(I-)50μg/L (NI)、0μg/L(LI1)、5 μg/L (LI2)、3000 μg/L (HI1)、10000μg/L (HI2)的去离子水.饲养12周后收集雌鼠尿液,测定基础尿碘值,然后将雌鼠同雄鼠合笼交配.分别于孕早期(第6～7天),孕中期(第12～ 13天)、孕晚期(第19～20天)处死,收集血清、羊水.采用砷铈催化分光光度法测尿碘及羊水碘,温和酸消化法测血清碘.结果 基础尿碘中位数LI1组、LI2组(5.96、15.92μg/L)均低于NI组(43.75μg/L,P均＜0.01)；HI1组、HI2组(5263.96、20389.64μg/L)均高于NI组(P均＜0.01).各组孕期尿碘中位数低于基础尿碘中位数(P均＜ 0.01).NI组孕早、中期尿碘中位数(28.97、34.34 μg/L)低于孕晚期(42.31 μg/L,P均＜0.01).血清碘LI1组、LI2组[(3.68±1.69)、(10.45±4.16)μg/L]低于NI组[(23.68±3.85)μg/L,P均＜0.05],HI1组、HI2组[(502.67±97.03)、(822.15±139.45)μg/L]均高于NI组(P均＜ 0.01).NI组血清碘随孕期进展逐渐降低,但差异无统计学意义(P均＞0.05).LI1组孕中期、孕晚期羊水碘中位数(0.85、3.00 μg/L)均低于同期NI组(3.56、7.91 μg/L,P均＜0.01)；LI2组孕中、晚期羊水碘中位数与同期NI组比较差异无统计学意义(P均＞0.05).HI1组孕中期、晚期羊水碘中位数(49.59、171.21 μg/L)均高于同期NI组(P均＜0.01),HI2组孕中期、晚期羊水碘中位数(98.76、544.77 μg/L)均高于同期NI组(P均＜ 0.01).各组大鼠孕晚期羊水碘均高于孕中期(P均＜0.01).LI1组、LI2组血清碘/尿碘比值(1.29±1.14、1.70±1.01)均高于NI组(0.51±0.37,P均＜0.01)；HII组、HI2组(0.21±0.07、0.11±0.07)均低于NI组(P均＜ 0.01).LI1、LI2组羊水碘/血清碘比值(0.19±0.15、0.32±0.17)均高于NI组(0.13±0.05,P＜0.01)；HI、HI2组(0.09±0.03、0.11±0.04)与NI组比较差异均无统计学意义(P均＞0.05).各组孕晚期羊水碘/血清碘比值均高于孕中期(P均＜0.01).各组大鼠羊水碘/尿碘比值结果同羊水碘/血清碘比值结果基本一致.结论 不同碘水平导致妊娠期大鼠体内碘代谢水平的改变,妊娠母体存在一种对自身及胎儿的保护机制,该机制能够减轻低碘及高碘环境对自身及胎儿造成的损伤作用.

abstractsObjective To study the effects of different iodine intakes on rat iodine metabolism during pregnancy.Methods One hundred and fifty female Wistar rats (body weight 80-100 g) were randomly divided into five groups:control group(NI),lower iodine 1 and 2 groups(LI1 and LI2),High iodine 1 and 2 groups(HI1 and HI2) by weight,30 rats in each group.These rats were given deionized water containing different concentrations of iodine,50(NI),0 (LI1),5(LI2),3000(HI1) and 10000 μg/L(HI2),respectively.After 12 weeks,urine samples were collected before copulation.The rats were sacrificed at the first(6-7 days),second (12-13 days) and third trimesters(19-20 days),respectively,serum and amniotic fluid samples were collected.Urinary iodine and iodine level in the fetal amniotic fluid were measured by As3+-Ce4+ catalytic spectrophotometry.Serum iodine was measured by mild acid digestion method.Results The baseline medians of urinary iodine of LI1 and LI2 groups(5.96,15.92 μg/L) were significantly lower than that of the NI group(43.75 μg/L,all P ＜ 0.01),and the values of HI and HI2 groups(5263.96,20389.64 μg/L) were significantly higher than that of the NI group (all P ＜ 0.01).The median of urinary iodine during pregnancy was significantly lower than that of the baseline of no pregnancy(all P ＜ 0.01).The medians of urinary iodine of the NI group at the first and the second trimesters (28.97,34.34 μg/L) were significantly lower than that of the third trimester(42.31 μg/L,all P ＜ 0.01).The means of serum iodine of LI1 and LI2 groups[(3.68 ± 1.69),(10.45 ± 4.16) μg/L] were significantly lower than that of the NI group [(23.68 ± 3.85)μg/L,all P ＜ 0.05],and the means of serum iodine of HI1 and HT2 groups [(502.67 ± 97.03),(822.15 ± 139.45)μg/L] were significantly higher than that of the NI group (all P ＜ 0.01).Although the mean of serum iodine of HI group gradually decreased with the progression of gestation,the difference was not statistically significant(all P ＞ 0.05).The iodine levels in amniotic fluid of fetal rats at the second and the third trimesters in LI1 group(0.85,3.00 μg/L) were significantly lower than that of the NI group(3.56,7.91 μg/L,all P ＜ 0.01),but the difference was not statistically significant between the iodine level in amniotic fluid of fetal rats of the LI2 and the NI groups at the second and the third trimesters(all P ＞ 0.05).The iodine levels in amniotic fluid of fetal rats at the second and the third trimesters in the HI1 group(49.59,171.21 μg/L) were significantly higher than that of the NI group(all P ＜ 0.01).The iodine levels in amniotic fluid of fetal rats at the second and the third trimesters in HI2 group (98.76,544.77 μg/L) were significantly higher than that of the NI group(all P ＜ 0.01).The iodine level in amniotic fluid of fetal rats in the third trimester was significantly higher than that of the second trimester in all the groups (all P ＜ 0.01).The ratios of serum iodine and urinary iodine of the LI1 and the LI2 groups (1.29 ± 1.14,1.70 ± 1.01) were significantly higher than that of the NI group(0.51 ± 0.37,all P ＜0.01),and that of the HI1 and the HI2 groups(0.21 ± 0.07,0.11 ± 0.07) were significantly lower than that of the NI group (all P ＜ 0.01).The ratios of amniotic fluid iodine and serum iodine of the LI and the LI2 groups (0.19 ± 0.15,0.32 ± 0.17) were significantly higher than that of the NI group(0.13 ± 0.05,P ＜ 0.01),but the difference was not statistically significant between HI1 and HI2 groups(0.09 ± 0.03,0.11 ± 0.04) and NI group(all P ＞ 0.05).The ratio of amniotic fluid iodine and serum iodine of the third trimester was significantly higher than that of the second trimester(all P ＜ 0.05).Conclusions Different iodine intake leads to changes in the levels of maternal iodine metabolism in rats during pregnancy.There probably is a protection mechanism in the mother's body,which protects the mother and the fetal from injury by iodine excess or iodine deficiency.