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目的观察不同碘营养水平对哺乳期大鼠甲状腺和乳腺促甲状腺激素受体(TSHR)mRNA表达水平的影响。方法30只雌性Wistar大鼠按体质量随机分成3组:低碘组(合成饲料,去离子水);适碘组(合成饲料,含碘150μg/L的去离子水);高碘组(合成饲料,含碘3 000μg/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TSHR mRNA表达水平。结果低碘组血清碘低于适碘组(P<0.05),高碘组血清碘高于适碘组(P<0.05);低碘组、高碘组T3水平低于适碘组(P<0.05);低碘组、高碘组T4水平与适碘组比较差异均无统计学意义(P>0.05),低碘组T4水平低于高碘组(P<0.05);低碘组甲状腺TSHR mRNA表达水平明显高于适碘组(P<0.05),高碘组低于适碘组,但差异无统计学意义;低碘组、高碘组乳腺TSHR mRNA表达水平都低于适碘组(P<0.05)。结论高碘时甲状腺和乳腺TSHR表达均减少,下调碘的摄入保护自身及子代免受碘过量的危害;轻度低碘时甲状腺提高TSHR表达以增加碘的摄入保护自身免受缺碘危害,但乳腺未增加摄碘能力,因此对子代没有保护作用或保护作用不明显。
Objective To observe the effects of different levels of iodine nutrition on thyroid and thyroid stimulating hormone receptor (TSHR) mRNA expression in lactating rats. Methods Thirty female Wistar rats were randomly divided into three groups according to body weight: low iodine group (synthetic feed, deionized water); suitable iodine group (synthetic feed, deionized water containing 150μg / L iodine); high iodine group Feed, iodine 3 000 μg / L deionized water). After feeding for 3 months, mates were mated with the males. The maternal rats were sacrificed 5 days after breast-feeding. Serum iodine was determined by mild acid digestion in the mammary glands, thyroid gland and serum of the mother rats. Radioimmunoassay was used to determine the levels of T3 and T4 Real-time fluorescence quantitative PCR was used to detect the expression of TSHR mRNA in breast and thyroid. Results Serum iodine in low iodine group was lower than that in iodine group (P <0.05), serum iodine in high iodine group was higher than that in iodine group (P <0.05) 0.05). The levels of T4 in low iodine group and high iodine group were not significantly different from those in the adequate iodine group (P> 0.05), while the T4 level in the low iodine group was lower than that in the high iodine group (P <0.05) (P <0.05). The levels of TSHR mRNA in the low iodine group and the high iodine group were lower than those in the iodine group (P <0.05), while those in the high iodine group were lower than those in the iodine group, but the difference was not statistically significant P <0.05). Conclusions TSHR expression in both thyroid and mammary gland is reduced in high iodine treatment, and iodine intake is reduced to protect themselves and their offspring from iodine excess. In mild hypothyroidism, thyroid increases TSHR expression to increase iodine intake and protects itself from iodine deficiency Hazard, but the breast does not increase iodine uptake capacity, so there is no protective effect on the offspring or protective effect is not obvious.