论文部分内容阅读
目的 观察长期过量碘摄入对小鼠血清脂蛋白代谢影响.方法 清洁级雌性断乳Balb/c小鼠60只,按体重随机分为6组(10只/组).在饮水中以KIO_3形式分别给予0(对照组),300,600,1200,2 400和4 800μg/L碘.30 d后,放射免疫法测定甲状腺激素,血清脂蛋白.PCR方法测定肝脏低密度脂蛋白受体(LDLR)、高密度脂蛋白受体(SR-B Ⅰ)基因表达水平.结果 各剂量组小鼠尿碘水平随着碘剂量升高明显增加(P＜0.01),血清四碘甲状腺原氨酸(TF4)、三碘甲状腺原氨酸(TT3)、促甲状腺激素(TSH)水平未发生明显性改变.2 400,4 800μ/L组血清总胆固醇(TC)与低密度脂蛋白一胆固醇(LDL-C)含量分别为(2.40±0.37),(2.58±0.42)和(0.39±0.11),(0.41±0.11)mmol/L,与对照组比较,差异有统计学意义(P＜0.05).LDLR mRNA表达水平星碘剂量依赖性降低(r=-0.753,P＜0.01).结论 长期过量碘摄人可致小鼠血清LDL-C水平升高.LDLR受体表达降低可能是过量碘摄入导致脂蛋白代谢紊乱的机制之一.“,”Objective To study the effect of excessive iodine exposure on serum lipoprotein metabolism in mice and to explore its possible mechanism.Methods Sixty female Balb/c mice were randomly divided into six groups according to body weight and given iodine at different dose of 0,300,600,1200,2 400,and 4 800μg/L,respectively,in drinking water.Serum lipoprotein and semm thyroid hormone were determined 30 days afteriodine exposure.The mRNA expression of low density lipoprotein receptor(LDLR)and scavenge receptor B Ⅰ(SR-B Ⅰ)were detected by real-time PCR.Results In excessive iodine groups,unnary iodine level increased dose-dependently and serum thyroid hormones(thyroid-stimulating hormone,total uiiodothyronine,and total thyroxine)were not affected by iodine intake throughout the study.A dose-dependent increase of serum low density lipoprotein-cholesterol(LDL-c)level was observed in iodine-treated groups.While there was no significant change in high density lipoprotein-cholesterol(HDL-c)level.Compared with the control group,total cholesterol and LDL-c levels increased significantly in 2400 and 4800μg/L groups(2.40±0.37,0.39±0.11,2.58±0.42,0.41±0.11 mmol/L).A dose-dependent attenuation of hepatic LDLR mRNA(r=-0.753,P＜0.01)expression in parallel to the change of serum LDL-C was obsorved.Conclusion The findings demonstrate a dose-dependent effect of excessive iodine on LDL-c and suggest that down-regulation of hepatic LDLR gone may play a critical role in excessive iodine-induced effect.