Shandong Institute of Prevention and Control for Endemic Disease, No.11 Yandong Road, Lixia District, Jinan, 250014, China.
Biol Trace Elem Res. 2013 Dec;155(3):416-22. doi: 10.1007/s12011-013-9811-8. Epub 2013 Sep 15.
The aim of the present study was to illustrate the combined effect of excess iodine and low-protein diet on the thyroid, and the potential molecular mechanism of this effect. One hundred ninety-two Wistar rats were randomly divided into the following groups: normal; 10- (10HI), 50- (50HI), or 100-fold excess iodine (100HI); low-protein; and low-protein combined with 10- (L10HI), 50- (L50HI), or 100-fold excess iodine (L100HI). At the end of 2, 4, or 6 months, the rats were sacrificed for iodine concentration and thyroid hormone analyses. The histological appearance of the thyroid gland was observed at the end of 6 months. At the end of 6 months, the serum total thyroxine (TT4), free thyroxine (FT4), total triiodothyronine (TT3), and free triiodothyronine (FT3) levels in the 100HI, L10HI, L50HI, and L100HI groups were significantly lower than the control group (P < 0.05 or P < 0.01). Serum TT4, FT4, TT3, and FT3 levels in the low-protein excess iodine groups were significantly lower than the groups with an equal amount of excess iodine alone (P < 0.05 or P < 0.01). Light and electron microscopy showed that excess iodine caused damage to the ultrastructure of thyroid and apoptosis of follicular epithelial cells. In the 100HI, L50HI, and L100HI groups, thyroid follicular epithelial cells became flattened, and follicles became distended with colloid. The damage was more serious in low-protein groups. The present findings demonstrated that the low-protein diet aggravated the damage to the thyroid caused by excess iodine alone.
本研究旨在阐明碘过量与低蛋白饮食对甲状腺的联合作用及这种作用的潜在分子机制。192 只 Wistar 大鼠随机分为以下几组：正常组；10 倍过量碘（10HI）组、50 倍过量碘（50HI）组或 100 倍过量碘（100HI）组；低蛋白组；以及低蛋白饮食联合 10 倍过量碘（L10HI）组、50 倍过量碘（L50HI）组或 100 倍过量碘（L100HI）组。在 2、4 或 6 个月结束时，处死大鼠以进行碘浓度和甲状腺激素分析。6 个月结束时观察甲状腺组织学外观。6 个月结束时，100HI、L10HI、L50HI 和 L100HI 组的血清总甲状腺素（TT4）、游离甲状腺素（FT4）、总三碘甲状腺原氨酸（TT3）和游离三碘甲状腺原氨酸（FT3）水平明显低于对照组（P<0.05 或 P<0.01）。低蛋白过量碘组的血清 TT4、FT4、TT3 和 FT3 水平明显低于单独等量碘过量组（P<0.05 或 P<0.01）。光镜和电镜显示，碘过量导致甲状腺超微结构损伤和滤泡上皮细胞凋亡。在 100HI、L50HI 和 L100HI 组中，甲状腺滤泡上皮细胞变平，滤泡内胶体扩张。低蛋白组损伤更严重。本研究结果表明，低蛋白饮食加重了碘单独过量对甲状腺的损伤。
