【摘要】 目的观察过量碘摄入对肝脏脂代谢的影响,并探讨其相关分子机制。方法清洁级雌性断乳Balb/c小鼠60只,按体重随机均分为6组。碘剂量分组为:A组0;B组,300μg/L;C组,600μg/L;D组,1200μg/L;E组2400μg/L;F组4800μg/L。第3月末,放射免疫法测定甲状腺激素水平,测定血清及肝脏总胆固醇(TC)、甘油三酯(TG)水平。通过实时聚合酶链反应(real-time PCR)方法测定肝脏固醇结合原件调节蛋白-1C(sterol regulatory element binding proteins1c,SREBP-1c)、脂肪酸合成酶(fatty acid synthase,FAS)基因表达水平。结果各剂量组小鼠的尿碘水平呈碘剂量依赖性升高。过量碘摄入导致血清总三碘甲状腺氨酸(TT3)水平降低,血清总甲状腺素(TT4)、促甲状腺激素(TSH)水平增加。在碘剂量≥2400μg/L时与对照组相比差异具有显著性。与对照组相比,血清TC、TG增加,肝脏TC、TG含量显著性增加,在碘剂量≥2400μg/L差异具有显著性。肝脏SREBP-1C、FAS基因表达水平增加在碘剂量≥2400μg/L差异具有显著性。结论过量碘摄入导致肝脏发生脂肪变性,SREBP-1c、FAS基因表达上调可能是过量碘摄入导致肝脏脂肪变性的机制之一。更多还原

【Abstract】 objective To study the effect of excessive iodine exposure on hepatic steatosis in mice and explore its possible mechanism.Method Sixty female Balb/c mice were equally divided into 6 groups according to body weight and given different doses of iodine at the levels of 0(A),300(B),600(C),1200(D),2400(E) and 4800μg/L(F) in drinking water for 3 mon.Then the levels of total cholesterol(TC) and triglyceride(TG) in serum and liver and serum thyroid hormones were determined.The expression of sterol regulatory element binding protein-1c(SREBP-1c) and fatty acid synthase(FAS) mRNA in liver were detected by real-time polymerase chain reaction(PCR).Results Urinary iodine level increased dose-dependently in all iodine groups,serum total triodothyronine(TT3) level decreased and serum total thyroxine(TT4),thyroid stimulating hormone(TSH) increased in 2400 μg/L or above iodine groups.The levels of TC and TG in serum and liver were significantly increased in 2400 μg/L or above iodine groups.Compared with the control group,the mRNA expression levels of SREBP-1c and FAS were increased in 2400 μg/L or above iodine groups.Conclusion Excessive iodine exposure could result in hepatic steatosis in mice.The up-regulation of SREBP-1c and FAS mRNA expression may involve in the mechanisms of exces-sive iodine induced hepatic steatosis.更多还原