碘缺乏和碘过多对大鼠甲状腺细胞膜脂流动性的影响

目的 探讨碘缺乏和碘过多对甲状腺细胞膜脂流动性的影响及其作用机理。方法 观察不同碘摄入水平的３组Ｗｉｓｔａｒ大鼠血清Ｔ４、Ｔ３水平,甲状腺组织超氧化物歧化酶（ＳＯＤ）和谷胱甘肽过氧化物酶（ＧＰＳ）的活力以及脂质过氧化产物丙二醛（ＭＤＡ）含量,应用荧光偏振方法测量了甲状腺细胞膜脂的荧光偏振度和平均微黏度,以反映膜脂的流动性,结果：低碘组大鼠血清Ｔ４、Ｔ３水平显低于适碘对照组及高碘组ＳＯＤ和ＧＰｘ活

A study on membrane fluidity of thyroid gland in rats with iodine deficiency or iodine excess

OBJECTIVES: To explore the effect of iodine deficiency and excess on thyroid membrane fluidity and its pathogenesis. METHODS: Wistar rats were fed different levels of iodine in the diet (normal iodine as control, low iodine and excess iodine). Serum T4 and T3 levels, thyroid superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities and malondialdehyde (MDA) content were determined, and two parameters of polarization (Pr) and micro-viscosity (eta) using DPH as a florescence probe were tested. RESULTS: Serum T4 and T3 levels in the low iodine (LI) group were markedly decreased, and the thyroid SOD and GPx activities and MDA content were significantly increased compared with the other two groups. However no changes were found in the high iodine (HI) group. There were no differences in Pr and eta values among three groups at 12th week of experiment, but at 24th week, both Pr and eta values in LI group were increased significantly compared to the other two groups. But the effect of iodine excess as expected was not found in this study. CONCLUSIONS: Long-term iodine deficiency caused a marked increase of membrane micro-viscosity and decrease of membrane fluidity in rat thyroid gland. Oxidative damage of thyroid by free radicals and retardation of lipid metabolism are considered as two important pathogenesis factors.