Yang Xue-Feng, Hou Xiao-Hui, Xu Jian, Guo Huai-Lan, Yinq Chen-Jiang, Chen Xiao-Yi, Sun Xiu-Fa
Department of Nutrition and Food Hygiene, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei, China.
Biomed Environ Sci. 2006 Aug;19(4):302-8.
To investigate the effect of selenium supplementation on the selenium status and selenoenzyme, especially the activity and mRNA expression of type 1 deiodinase (D1) in mice with excessive iodine (EI) intake and to explore the mechanism of selenium intervention on iodine-induced abnormities.
Weanling female BALB/c mice were given tap water or 3 mg/L of iodine or supplemented with 0.5 mg/L or 1.0 mg/L of selenium in the presence of excessive iodine for 5 months. Selenium status, thyroid hormone level, hepatic and renal D1 activity and mRNA expression were examined.
Excessive iodine intake significantly decreased the selenium concentration in urine and liver, and the activity of glutathione peroxidase (GSH-Px) in liver. Meanwhile, serum total T4 (TT4) increased while serum total T3 (TT3) decreased. Hepatic D1 enzyme activity and mRNA expression were reduced by 33% and 86%, respectively. Renal D1 enzyme activity and mRNA were reduced by 30% and 55%, respectively. Selenium supplementation obviously increased selenium concentration, activity of GSH-Px and Dl as well as mRNA expression of D1. However, increasing the supplementation of Se from 0.5 to 1.0 mg/L did not further increase selenoenzyme activity and expression.
Relative selenium deficiency caused by excessive iodine plays an essential role in the mechanism of iodine-induced abnormalities. An appropriate dose of selenium supplementation exercises a beneficial intervention.
探讨补硒对碘过量摄入小鼠硒状态和硒酶的影响，特别是对1型脱碘酶（D1）活性及mRNA表达的影响，并探讨硒干预碘诱导异常的机制。
将断乳雌性BALB/c小鼠分为三组，分别给予自来水、3 mg/L碘水，以及在碘过量情况下补充0.5 mg/L或1.0 mg/L硒，持续5个月。检测小鼠的硒状态、甲状腺激素水平、肝脏和肾脏D1活性及mRNA表达。
过量碘摄入显著降低小鼠尿硒和肝硒浓度，以及肝脏谷胱甘肽过氧化物酶（GSH-Px）活性。同时，血清总T4（TT4）升高而血清总T3（TT3）降低。肝脏D1酶活性和mRNA表达分别降低33%和86%。肾脏D1酶活性和mRNA分别降低30%和55%。补硒明显提高了硒浓度、GSH-Px活性、D1活性以及D1的mRNA表达。然而，将硒补充量从0.5 mg/L增加到1.0 mg/L并没有进一步提高硒酶活性和表达。
碘过量导致的相对硒缺乏在碘诱导异常机制中起重要作用。适当剂量的补硒具有有益的干预作用。
