不同碘营养水平对哺乳期大鼠甲状腺和乳腺胰岛素样生长因子Ⅰ mRNA表达的影响

摘要

Objective To study the effects of different levels of iodine concentration on insulin-like growth factors Ⅰ (IGF-1) mRNA expression of thyroid and breast in lactating rats. Methods Thirty Wistar female rats, having been weaned for 1 month, were randomly divided into three groups according to their body weights, i. e. :low iodine(LI) group,adequate iodine(AI) group, high iodine(HI) group, 10 rats in each group. Synthetic fodder and deionized water containing iodine of 0,150,3000 μg/L was respectively fed to these rats. After fed for 3 months, the rats mated and had offspring. Their mammary glands, thyroids and serum were sampled at lactation day 5. The serum iodine of lactating rats were determined by moderate acid digestion method, level of T3 and T4 were determined by radioimmunoassay method, and the expressions of IGF-1 mRNA of mammary glands and thyroids were determined by real-time fluorescence quantitative PCR assay. Results The value of serum iodine of LI group [(17.38±3.27) μg/L] was lower than that of AI group [(43.42±6.92) μg/L, P<0.05], and the value of serum iodine of HI group[(350.10±38.46)μg/L] was higher than that of AI group (P<0.05). The level of T3 of LI group and HI group[ (1.11±0.25), (1.61±0.33)μg/L] reduced obviously compared with that of AI group[(2.18±0.46) μg/L, P<0.05]. The mean of T4 of LI group and HI group[(33.40±11.11),(56.54±10.38)μg/L] had no statistical significance compared with AI group(44.02±12.51)μg/L, P>0.05), but the level of T4 of LI group was lower than that of HI group(P<0.05). The level of IGF-1 mRNA expression of thyroid in LI group and HI group (0.34±0.08, 0.23±0.08) was higher than that of AI group(0.15±0.03, P<0.05). The level of IGF-1 mRNA expression of lactating mammary in LI group(0.59±0.18) was higher than that of AI group(0.40±0.10, P<0.05). The level of IGF-1 mRNA expression of thyroid was lower than that of breast between the same group(t=3.54, 6.44,2.62, all P<0.05). Conclusion Iodine could affect IGF-1 mRNA expression of thyroid and lactating mammary, and IGF-1 mRNA expression of lactating mammary was stronger than that of the thyroid.%目的 观察不同碘营养水平对哺乳期大鼠甲状腺和乳腺胰岛素样生长因子Ⅰ(IGF-1)mRNA表达水平的影响.方法 30只雌性断乳1个月Wistar大鼠按体质量随机分成3组:低碘组、适碘组、高碘组,每组10只,食用合成饲料,分别饮用含碘0、150、3000 μg/L的去离子水.喂养3个月后,与雄鼠合笼交配,待母鼠哺乳5 d后将其处死、取母鼠乳腺、甲状腺及血清,温和酸消化法测定血清碘,放射免疫分析法测定T3、T4水平,实时荧光定量PCR法检测乳腺和甲状腺IGF-1 mRNA表达水平.结果 低碘组血清碘[(17.38±3.27)μg/L]低于适碘组[(43.42±6.92)μg/L,P<0.05],高碘组血清碘[(350.10±38.46)μg/L]高于适碘组(P<0.05);低碘组、高碘组T3水平[(1.11μ0.25)、(1.61±0.33)μg/L]低于适碘组[(2.18±0.46)μg/L,P均<0.05];低碘组、高碘组T4水平[(33.40±11.11)、(56.54±10.38)μg/L]与适碘组[(44.02±12.51)μg/L]比较差异无统计学意义(P>0.05),低碘组T4水平低于高碘组(P均<0.05);低碘组、高碘组甲状腺IGF-1 mRNA表达水平(0.34±0.08、0.23±0.08)均高于适碘组(0.15±0.03,P均<0.05);低碘组哺乳期乳腺IGF-1 mRNA表达水平(0.59±0.18)高于适碘组(0.40±0.10,P<0.05);3组甲状腺IGF-1 mRNA表达均低于同组的乳腺表达水平(t=3.54、6.44、2.62,P均<0.05).结论 碘能够影响哺乳期甲状腺和乳腺IGF-1 mRNA的表达,且哺乳期乳腺表达强于甲状腺.