不同碘水平对哺乳期母鼠和仔鼠的甲状腺功能及子代生长发育的影响

Maternal and child′s thyroid function and child′s growth and development during lactation with different iodine supply in diet

目的研究不同碘水平对哺乳期母鼠和仔鼠的甲状腺功能以及子代生长发育的影响。方法Wistar母鼠随机分为4组:重度缺碘组(SID)、轻度缺碘组(MiID)、正常碘组(NI)、碘过量组(ExI)。所有大鼠均食用缺碘饲料,饮水给予不同剂量的碘化钾,喂养3个月后交配,检测哺乳14 d时母鼠及其仔鼠的尿碘、乳汁碘和血液甲状腺激素(TH)水平,观察仔鼠的体格发育和神经发育的情况,采用MIAS-2000图像分析系统测量生后10、14、20、25、28日龄仔鼠小脑外颗粒层(EGL)厚度。结果(1)母鼠及仔鼠尿碘、乳汁碘均随饮食碘供给量的增加而增加,其组间变化幅度以母鼠尿碘为最高、仔鼠尿碘次之、乳汁碘最低;(2)SID组母鼠血清TT4、TT3/TT4比值升高,仔鼠TT4降低,与NI组比较有统计学意义,而MiID和ExI组无论母鼠和仔鼠均与NI组无明显差异;(3)SID组仔鼠体格和神经发育明显落后于NI组,小脑EGL增殖和消退明显延迟;MiID和ExI组仔鼠的各项发育指标与NI组无明显差别。结论母亲重度缺碘会严重影响子代的生长发育和神经发育,但在轻度缺碘和碘过量(正常碘的30倍左右)时,通过母体的代偿作用可以保证子代正常的碘营养、甲状腺功能以及生长发育。

Objective To study lactating mother and child＇s thyroid function and child＇s postnatal growth and development with different iodine supply in diet. Methods Wistar rats were randomly divided into severe iodine deficiency （ SID）, mild iodine deficiency （MiID）, normal iodine （NI） and excessive iodine （ExI） groups. All rats were fed on an iodine deficient food and drinking water with different doses of KI for 3 months until to mating. The urinary iodine, milk iodine and thyroid hormones （TH） were detected in lactating mother and their young rats on 14 days after birth. The physical growth and nervous development of these off - springs were observed. The thickness of EGL in cerebellum was measured using MIAS - 2000 Image Analysis Sys- tem in young rats on 10, 14, 20 25, and 28 day. Results （1） Iodine contents in urine and milk of lactating rats and off - spring were increased with the increase of iodine supplied in diet. But the change amplitude between groups was decreased one by one： urine iodine in lactating rats 〉 urine iodine in off - spring 〉 milk iodine. （2） Serum TT4 were significantly decreased, but TT3/ TT4 increased in lactating rats of SID group compared with NI, so as TT4 of offspring rats in SID. MiID and ExI groups were not. （3） The physical growth and nervous development in SID group were significantly lagging behind compared with NI group. The proliferation and disappearance of EGL in SID were delayed, bat no difference among MilD, ExI and NI groups. Conclusions Severe Iodine deficiency will affect the postnatal growth and development of offspring rat, while that will be normal in mild iodine deficiency and high iodine by maternal compensation.