大鼠孕期甲状腺功能及自身抗体变化的研究

Changes of thyroid function and autoantibodies during the pregnancy of rats

目的 观察Wistar大鼠正常孕期不同阶段甲状腺功能及自身抗体的变化规律.方法 SPF/VAF级健康成年雌性Wistar大鼠64只,按随机数字法分为对照组、孕早期组、孕中期组、孕晚期组,每组各16只.后3组雌鼠与雄鼠合笼成功交配后,分别于孕7d、14d、20 d对雌鼠采用代谢笼收集尿液、股动脉放血处死,对照组与孕中期组同批处理.采用过硫酸铵消化-砷铈催化分光光度法测定尿碘浓度,化学发光免疫分析法测定总T3、总T4、游离T3、游离T4、促甲状腺激素（TSH）水平,放射免疫分析法测定甲状腺球蛋白（Tg）、甲状腺球蛋白抗体（TgAb）、甲状腺过氧化物酶抗体（TPOAb）水平.结果 4组间尿碘水平差异无统计学意义（x2=2.798,P ＞0.05）.孕早期组总T3水平高于对照组,而孕中期组、孕晚期组总T3水平低于孕早期组（F =3.775,P＜0.05）.与对照组相比,孕早期组总T4水平升高,而孕中期组及孕晚期组水平依次降低（P＜0.05）.游离T3、游离T4水平有随孕期延长而逐渐下降的趋势,且孕中期组、孕晚期组与其余两组相比差异有统计学意义（F =34.718,41.715,P均＜0.01）.游离T3/游离T4比值随孕期延长逐渐升高.与对照组相比,孕早期组、孕中期组、孕晚期组TSH水平依次升高,且孕中期组、孕晚期组差异有统计学意义（x2=16.101,P＜0.01）.Tg、TgAb、TPOAb水平在各组间差异均无统计学意义（P均＞0.05）.结论 Wistar大鼠甲状腺功能在孕期不同阶段存在动态变化,与人体孕期变化规律基本一致,但大鼠孕期未显示甲状腺自身抗体的明显改变,提示大鼠有可能用于人类孕期实验研究.

Objective To study the changes of thyroid function and autoantibodies in each trimester of pregnancy in Wistar rats.Methods Sixty-four healthy female aduh SPF/VAF weaning Wistar rats were divided into 4 groups according to a random number table：control group,the 1st trimester group,the 2nd trimester group and the 3rd trimester group,with 16 rats in each group.Rats in the latter 3 groups were mated with male rats.Urine from pregnant rats were collected with metabolism cages and blood samples were collected by exsanguination from femoral artery at the 7th,14th and 20th day of their pregnancy,respectively.Rats in control group and rats in the 2nd trimester group were treated at the same time.Urinary iodine concentration （UIC） was determined by As3＋-Ce4＋ catalytic spectrophotometry using ammonium persulfate digestion.Serum total triiodothyronine （TT3） and thyroxine （TT4）,free triiodothyronine（FT3） and thyroxine （FT4）,and thyroid stimulating hormone （TSH） were measured by chemiluminescence immunoassay.Serum thyroglobulin （Tg）,thyroglobulin antibody （TgAb） and thyroid peroxidase antibody（TPOAb） were determined by radioimmunoassay.Results UIC of all groups showed no significant differences （x2=2.798,P 〉0.05）.TT3 level of the 1st trimester group was increased compared with control group,but were decreased later in the 2nd and 3rd trimester group （F =3.775,P 〈 0.05）.Compared with control group,TT4 was higher in the 1 st trimester group but were lower in the 2nd and 3rd trimester group with TT4 decreased more in the 3rd trimester group （P〈0.05）.FT3 and FT4 had a trend to decrease after pregnancy and the differences between the 1 st and the 2nd trimester group and the other two groups were significant （F=34.718,41.715,all P 〈0.01）.FT3/FT4 ratio gradually increased throughout pregnancy.Compared with control group,TSH in the 1st,2nd and 3rd trimester group were progressively increased,and in the 2nd and 3rd trimester group,the differences were significant （x2=16.101,P 〈0.01）.There was no significant difference of Tg,TgAb,TPOAb among all groups （all P 〉0.05）.Conclusion Thyroid function is different in different trimester of pregnancy in Wiatar rats,which is similar to human.But there is no alteration of thyroid autoantibodies during pregnancy of rats.Rat may be a useful model to study human pregnancy.