摘要目的 研究碘摄入量对高脂血症小鼠甲状腺功能及血脂代谢的影响.方法 将4周龄雌性c57BL/6J小鼠50只随机分为重度低碘组(SID)、轻度低碘组(MID)、适碘组(NI)、10倍碘过量组(10HI)、50倍碘过量组(50HI),每组10只.均用高脂、高胆固醇、低碘(碘含量为20～40 μg/kg)饲料喂养.SID组饮用去离子水,其余4组饮用含有不同浓度碘化钾的去离子水.32周时处死动物,测定外周血甲状腺激素和血脂水平.观察主动脉病理学改变.检测主动脉组织细胞间黏附分子-1(ICAM-1)、血管细胞黏附分子-1(VCAM-1)和肝组织低密度脂蛋白受体(LDL-R)mRNA表达水平.结果 (1)SID组和MID组总T4和总T3水平较NI组均显著降低(P＜0.05).(2)SID组甘油三酯(TG)、总胆固醇(TC)和低密度脂蛋白-胆固醇(LDL-C)水平均较NI组明显上升(P＜0.01).MID组LDL-C水平明显高于NI组(P＜0.01).10HI组和50HI组TC水平均明显低于NI组(P＜0.01).(3)NI组主动脉内膜内皮下间隙明显增宽,可见脂质沉积.MID组和SID组主动脉内膜内皮下间隙较NI组进一步增宽,部分区域可见散在泡沫细胞,其周围有少量脂质,可见脂纹形成.10HI组和50HI组中只见主动脉内膜内皮下间隙稍有增宽,染色浅淡.(4)SID组主动脉组织ICAM-1mRNA、VCAM-1 mRNA和MID组主动脉组织ICAM-1 mRNA表达水平均较NI组显著升高(P＜0.01),而肝组织LDL-R mRNA表达水平均明显降低(P＜0.01).50HI组主动脉组织ICAM-1 mRNA和VCAM-1 mRNA表达水平明显低于NI组(P＜0.05或P＜0.01).10HI组和50HI组中肝组织LDL-R mRNA表达水平均较NI组升高(P＜0.01).结论 膳食中的碘可通过影响小鼠甲状腺功能及血脂代谢及动脉组织黏附分子的表达,参与高脂、高胆固醇喂养小鼠的动脉粥样硬化形成.低碘可加重高脂血症小鼠的动脉损伤,10倍和50倍高碘可减轻高脂血症小鼠的动脉损伤.

abstractsObjective To evaluate the effects of dietary iodine intake on the thyroid function and lipid metabolism of hyperlipemia mice. Methods 4-week old female c57 BL/6J mice( n = 50), were randomly divided into: severe iodine deficiency ( SID ) group, mild iodine deficiency ( MID ) group, normal iodine ( NI )group, 10-fold high iodine (10HI)group and 50-fold high iodine (50HI)group, 10 in each group. All the mice were fed by high fat,high cholesterol,low iodine foldder( iodine content is 20-40 μg/kg) and drank deionized water containing different concentrations of potassium iodide except for SID group. 32 weeks later,all the animals were sacrificed. Serum thyroid hormones and the levels of lipid were measured. The extent of lesion development in the proximal aorta or aortic root was observed. The expressions of intercellular adhesion molecule (ICAM)-1 mRNA and vascular cell adhesion molecule (VCAM)-1 mRNA in aorta and low density lipoprotein ( LDL)-receptor mRNA in liver were detected. Results ( 1 )Total T4 and total T3 were distinctively decreased in SID and MID, comparied with NI ( P ＜ 0. 05 ). (2) The levels of serum triglyceride, total cholesterol and LDL cholesterol(LDL-C) in SID and LDL-C in MID were obviously higher than those in NI (P ＜0.01 ). In contrast,the levels of total cholesterol in both 10HI and 50HI were statistically lower than those in NI (P ＜0.01 ). (3) Pathological changes showed that in the tunica intima,sub-endothelial space was obviously wider with lipids deposition in NI. In MID and SID,sub-endothelial space was progressively wider and foam cells were found in regional area with some lipids around them, called fatty streak formation. In 10HI and 50 HI, sub-endothelial space was just slightly wider and the staining was pale. (4) Both ICAM-1 and VCAM-1 mRNA in the aorta tissues were highly expressed in SID than those in NI (P ＜0.01 ). Similarly,the expression level of ICAM-1 mRNA in MID was higher than that in NI (P＜0. 01). In contrast,much lower expressions of these adhesion molecules were detected in 50HI compared with NI ( P ＜ 0.01 or P ＜ 0. 05 ). The expression levels of LDL-R mRNA in liver in SID and MID were much lower while higher in 10HI and 50 HI than those in NI ( P ＜ 0.05 or P ＜ 0. 01 ). Conclusions Dietary iodine intake could influence the development of atherosclerosis in mice fed by lipid-enriched diets by regulating thyroid function, the metabolism of serum lipids. Iodine deficiency can aggravate while 10-fold and 50-fold high iodine intake can alleviate the lesions of the aorta in hyperlipemia mice.