硒对高碘小鼠肝脏两种含硒酶的影响

目的:研究硒对高碘小鼠肝脏含硒酶的影响,探讨硒干预高碘危害的机制。方法:40只雌性Balb/c小鼠按体重随机分为4组:正常对照组(NC);高碘对照组(HI),饮用3.0mg/LI的高碘水;高碘+硒I组(HI+Se1),高碘水中补充0.5mg/LSe;高碘+硒II组(HI+Se2),高碘水中补充1.0mg/LSe。5个月后,观察甲状腺病理变化,测定血清总T4(TT4)、总T3(TT3)、反式T3(rT3)水平以及肝脏硒含量、谷胱甘肽过氧化物酶(GSH-Px)活性、1型脱碘酶(DI-1)活性及mRNA表达。结果:高碘组小鼠出现了弥漫胶质性甲状腺肿;与正常对照组相比,高碘组的血清TT4水平显著升高,TT3水平显著降低;而补硒可显著抑制TT4的升高和TT3的降低;高碘组肝脏硒含量降低,MDA含量显著升高,GSH-Px和DI-1活性分别降低了47%和33%,DI-1mRNA的表达也下调。而两个补硒组能显著升高肝硒含量,增强GSH-Px活性以及DI-1活性和表达,其中以0.5mg/L的硒剂量作用最为明显。结论:适当剂量的硒可通过影响含硒酶的活性和mRNA的表达来发挥对高碘危害的干预作用。

INFLUENCE OF SELENIUM SUPPLEMENTAT ION ON THE HEPATIC SELENOENZYMES IN MICE FED WITH HIGH IODINE DIET

Objective: To observe the influence of selenium supplementation on the hepatic selenoenzymes in mice fed with high iodine diet and to explore the mechanism. Methods: Forty weanling female Balb/C mice were assigned into 4 groups and given drinking water including different doses of iodine and selenium: normal control (NC, tap water),high iodine group (HI, 3.0 mg/L I),high iodine+selenium group 1 (HI+Se 1,3.0 mg/L I +0.5 mg/L Se) and high iodine + selenium group 2 (HI+Se 2,3.0 mg/L I +1.0 mg/L Se). Five months later, the related indices were determined. Results: The mice in HI group showed colloid goiter. Compared with NC group, serum TT4 increased and TT3 decreased significantly in HI groups. Two Se supplementation groups inhibited the increase of TT4 and the decrease of TT3. In HI group, the liver Se reduced, MDA increased,activity of GSH-Px and deiodinase 1(DI-1)were reduced 47% and 33% respectively,and mRNA expression of DI-1 also down-regulated. Se supplementation obviously increased the hepatic selenium, enhanced the activity of GSH-Px and DI-1 and mRNA expression of DI-1. However,increase of Se supplementation from 0.5 to 1.0 mg/L did not further increase selenoenzyme activity and expression. Conclusion: Intervention of Se on the iodine-induced abnormalities is fulfilled by its effect on selenoenzyme.