碘对哺乳期大鼠甲状腺和乳腺钠碘转运体、胰岛素样生长因子Ⅰ及转化生长因子βmRNA表达的影响

摘要

Objective To observe the influence of iodine on mRNA expression of iodide transporter (NIS),insulin-like growth factor Ⅰ (IGF- Ⅰ ) and transforming growth factor beta(TGF-β) in thyroid and mammary glands of lactating rats and to explore the role of NIS,IGF- Ⅰ and TGF-β mRNA in iodine uptake in thyroid and mammary glands of lactating rats.Methods One hundred and one Wistar rats(80 female and 21 male),weighting 8 - 100 g were selected.These female rats were randomly divided into five groups according to their body weight:control group(NI,normal feed,drank deionized water containing iodine 50 μg/L) ; low iodine group 1 and 2(LI-1,LI-2,low iodine feed,drank deionized water containing iodine 0 and 5 μg/L,respectively); high iodine group 1 and 2(HI-1,HI-2,normal feed,drank deionized water containing iodine 3000 and 10 000 μg/L,respectively),16 rats in each group.After feeding for 3 months,the female and male rates were mated 3:1.The female rats in each group were sacrificed at the fifth and tenth day after postpartum.Thyroid and mammary glands were taken.The mRNA levels of NIS,IGF- Ⅰ and TGF-β in thyroid and mammary glands of lactating rats were determined by real time quantitative PCR.Results The fifth days after postartum,NIS,IGF- Ⅰ and TGF-β mRNA expression levels of thyroid and lactating mammary glands were different between groups,and the differences were statistically significant ( NIS:F =631.46,64.91,all P ＜ 0.01 ; IGF- Ⅰ:F =11.45,6.56,all P ＜ 0.01 ; TGF-β:F =291.83,304.53,all P ＜ 0.01).Compared with control group [NIS:0.0066 ± 0.0023, (0.1481 ± 0.0711 ) × 10-2; IGF- Ⅰ:0.0419 ± 0.0062,0.0542 ± 0.0044; TGF-β:0.1416 ± 0.0277,0.1670 ± 0.0499],regardless of thyroid or mammary gland,the NIS,IGF- Ⅰ and TGF-β mRNA expression of LI-1 [NIS:0.0447 ± 0.0110,(0.3030 ± 0.1831) × 10-2;IGF- Ⅰ:0.0662 ± 0.0078,0.0902 ± 0.008; IGF- Ⅰ:0.5514 ± 0.0508,0.6942 ± 0.0367],LI-2[NIS:0.0317 ±0.0081,(0.3017 ± 0.1601) × 10-2; IGF-I:0.0645 ± 0.0054,0.0894 ± 0.0093; TGF-β:0.5292 ± 0.0332,0.6704 ± 0.0277 ] was significantly increased (all P ＜ 0.01 ); the NIS mRNA expression of HI-1 [0.0043 ± 0.0011,(0.1233 ± 0.0954) × 10-2],HI-2[0.0037 ± 0.0017,(0.1058 ± 0.0854) × 10-2] was decreased(all P ＜ 0.05),while the expression of IGF-Ⅰ mRNA [0.0521 ± 0.0910,0.0715 ± 0.0026; 0.0516 ± 0.0078,0.0697 ± 0.0038] and TGF-β mRNA [0.2087 ± 0.0425,0.2361 ± 0.0425; 0.1971 ± 0.0237,0.2257 ± 0.0752 ] was increased (all P ＜ 0.05 ).The tenth days after postpartum,the mRNA expression levels of NIS,IGF- Ⅰ and TGF-β of thyroid and lactating mammary gland in rats were different between groups,and the differences were statistically significant (NIS:F =103.55,116.32,all P ＜ 0.01; IGF-Ⅰ:F =67.67,11.98,all P ＜ 0.01; TGF-β:F =74.30,381.30,all P ＜0.01 ).Compared with the control group[NIS:0.0069 ± 0.0011,(0.1337 ± 0.0599) × 10-2; IGF-Ⅰ:0.0390 ±0.0071,0.0534 ± 0.0056; TGF-β:0.1351 ± 0.0336,0.1534 ± 0.0320],the mRNA expression levels of NIS,IGF- Ⅰ and TGF-β of LI-1 [ NIS:0.0432 ± 0.0165,(0.2962 ± 0.0985 ) × 10-2; IGF- Ⅰ:0.0643 ± 0.0088,0.0873 ± 0.0055 ; TGF-β:0.5042 ± 0.0912,0.6408 ± 0.0420],LI-2[NIS:0.0287 ± 0.0111,(0.2873 ± 0.0862) × 10-2; IGF- Ⅰ:0.0621 ± 0.0094,0.0862 ± 0.0038; TGF-β:0.4893 ± 0.0504,0.6372 ± 0.0389] were significantly increased(all P ＜ 0.01 ); the NIS mRNA levels of HI-1 [ 0.0042 ± 0.0029,(0.1006 ± 0.0909) × 10-2],HI-2[0.0035 ± 0.0020,(0.0890 ± 0.0119) × 10-2] were decreased(all P＜ 0.05),while the expression of IGF-Ⅰ mRNA[0.0516 ± 0.0078,0.0668 ± 0.0071; 0.0508 ± 0.0089,0.0621 ± 0.0064] and TGF-β mRNA[0.2007 ± 0.0546,0.2175 ± 0.0370;0.1959 ± 0.0393,0.2097 ± 0.0425] were increased(all P ＜ 0.05 ).In thyroid and mammary glands,the comparisons of NIS,IGF,TGF-β mRNA expression of the fifth and tenth day after postartum,between each group were not statistically significant(all P ＜ 0.05).Conclusions There are regulatory mechanisms of thyroid and mammary glands of lactating rats in response to low or high iodine conditions.In low iodine,the expressions of NIS,IGF- Ⅰ and TGF-β mRNA in thyroid and mammary glands increase and iodide uptake ability is enhanced to meet the body needs.In high iodine,the expression of NIS mRNA decreases in thyroid and mammary glands.Due to the reduced ability of iodine uptake,iodine intake is reduced,thereby reducing the hazards of high iodine in filial rats.%目的 观察碘对哺乳期大鼠甲状腺和乳腺钠碘转运体(NIS)、胰岛素样生长因子Ⅰ(IGF-Ⅰ)、转化生长因子β (TGF-β)mRNA表达的影响,探讨NIS、IGF-Ⅰ 、TGF-β mRNA在哺乳期大鼠甲状腺和乳腺摄碘中的作用.方法 选择Wistar大鼠101只,其中雌性80只,雄性21只,体质量80- 100g.按体质量将雌性大鼠随机分为5组:对照组(正常饲料、饮含碘50μg/L去离子水),低碘1组、2组(低碘饲料,分别饮用去离子水、含碘5 μg/L去离子水),高碘1组、2组(正常饲料,分别饮用含碘3000、10 000 μg/L去离子水),每组16只.在喂养3个月后,将雌鼠与雄鼠按3∶1合笼交配,在产后第5、10天,分别处死各组雌鼠,取甲状腺和乳腺,采用实时荧光定量PCR检测哺乳期大鼠甲状腺和乳腺NIS、IGF-Ⅰ 、TGF-β mRNA表达.结果 产后第5天,哺乳期大鼠甲状腺和乳腺的NIS、IGF-Ⅰ 、TGF-β mRNA表达组间比较差异均有统计学意义(NIS:F值分别为631.46、64.91,P均＜0.01；IGF-Ⅰ:F值分别为11.45、6.56,P均＜0.01；TGF-β:F值分别为291.83、304.53,P均＜0.01).与对照组大鼠甲状腺和乳腺NIS、IGF-Ⅰ 、TGF-β mRNA[NIS:0.0066±0.0023、(0.1481±0.0711)×10-2;IGF-Ⅰ:0.0419±0.0062、0.0542±0.0044;TGF:0.1416±0.0277、0.1670±0.0499]比较,低碘1组[NIS:0.0447±0.0110、(0.3030±0.1831)× 10-2;IGF-Ⅰ:0.0662±0.0078、0.0902±0.008;TGF-β:0.5514±0.0508、0.6942±0.0367]、2组[NIS:0.0317±0.0081 、(0.3017±0.1601)×10-2;IGF-Ⅰ:0.0645±0.0054、0.0894±0.0093;TGF-β:0.5292±0.0332、0.6704±0.0277]表达明显升高(P均＜0.01)；高碘1组NIS mRNA[0.0043±0.0011、(0.1233±0.0954)×10-2]、2组NIS mRNA[0.0037 ±0.0017、(0.1058±0.0854)×10-2]表达降低(P均＜0.05),但IGF-Ⅰ [0.0521±0.0910、0.0715±0.0026;0.0516±0.0078、0.0697±0.0038] 、TGF-β mRNA[0.2087±0.0425、0.2361±0.0425;0.1971±0.0237、0.2257±0.0752]表达升高(P均＜0.05).产后第10天,哺乳期大鼠甲状腺和乳腺的NIS、IGF-Ⅰ 、TGF-β mRNA表达组间比较差异均有统计学意义(NIS:F值分别为103.55、116.32,P均＜ 0.01;IGF-Ⅰ:F值分别为67.67、11.98,P均＜0.01；TGF-β:F值分别为74.30、381.30,P均＜0.01).与对照组大鼠甲状腺和乳腺NIS、IGF-Ⅰ 、TGF-β mRNA[NIS:0.0069±0.0011 、(0.1337±0.0599)× 10-2;IGF-Ⅰ:0.0390±0.0071、0.0534±0.0056;TGF-β:0.1351±0.0336、0.1534±0.0320]比较,低碘1组[NIS:0.0432±0.0165、(0.2962±0.0985)× 10-2;IGF- Ⅰ:0.0643±0.0088、0.0873±0.0055;TGF-β:0.5042±0.0912、0.6408±0.0420]、2组[NIS:0.0287±0.0111、(0.2873±0.0862)×10-2;IGF-Ⅰ:0.0621±0.0094、0.0862±0.0038;TGF-β:0.4893±0.0504、0.6372±0.0389]表达明显升高(P均＜0.01)；高碘1组NIS mRNA [0.0042±0.0029、(0.1006±0.0909)× 10-2]、2组NIS mRNA [0.0035±0.0020、(0.0890±0.0119)×10-2]表达降低(P均＜0.01),但IGF-Ⅰ [0.0516±0.0078、0.0668±0.0071;0.0508±0.0089、0.0621±0.0064] 、TGF-β mRNA [0.2007±0.0546、0.2175±0.0370;0.1959±0.0393、0.2097±0.0425]表达升高(P均＜0.05).各组大鼠产后第5天与第10天比较,无论是甲状腺还是乳腺,NIS、IGF-Ⅰ 、TGF-β mRNA表达差异无统计学意义(P均＞0.05).结论 哺乳期大鼠甲状腺和乳腺对碘存在调控机制,低碘时甲状腺和乳腺NIS 、IGF-Ⅰ 、TGF-β mRNA表达增多,摄碘能力增强,满足机体的需要；高碘时甲状腺和乳腺NIS mRNA表达减少,由于摄碘能力降低,碘的摄入减少,减轻了高碘对仔鼠的危害.