碘/钠摄入量对小鼠血脂代谢影响的实验研究

目的 探讨膳食碘摄入量对适钠和低钠饮食小鼠血脂代谢影响,为揭示碘与心血管疾病发病的相关性进行初步研究.方法 Balb/c小鼠260只,按体质量、性别随机分为适钠组(Na)和低钠组(Lna),每组130只;此两大组又分别按照碘摄入量分为①重度低碘组(SID);②轻度低碘组(MID);③适碘组(NI);④10倍碘过量组(10HI);⑤50倍碘过量组(50HI),总计为10组,每组26只.各组小鼠在饲养8个月时收集尿液和小鼠外周血,分离血清.测定小鼠尿碘、体质量、血脂甘油三酯(TG)、总胆固醇(TC)、低密度脂蛋白(LDL)、高密度脂蛋白醇(HDL)]及甲状腺激素水平总甲状腺素(TT4),总三碘甲腺原氨酸(TT3)、游离甲状腺素(FT4)、游离三碘甲腺原氨酸(FT3)].结果适钠组中,SID组、MID组雄性小鼠TG水平(1.64±0.35)、(1.67±0.31)mmol/L]和SID组TC水平(3.88±0.35)mmol/L]明显高于NI组(1.49±0.42)、(3.25±0.47)mmol/L,P均＜0.05],SID组中雌性小鼠TG水平(1.52±0.22)mmol/L]高于NI组(1.23±0.22)mmol/L,P＜0.05].10HI和50HI组雄性小鼠外周血TG水平(1.16±0.23)、(1.21±0.27)mmol/L]低于NI组(P均＜0.05),雌性小鼠TC水平(2.37±0.49)、(2.48±0.37)mmol/L)低于NI组(2.84±0.37)mmol/L,P均＜0.05].在低钠组,SID组雄性小鼠TG、TC水平(1.39±0.40)、(3.33±0.46)mmol/L]均高于NI组(1.30±0.28)、(3.00±0.53)mmol/L,P均＜0.05],SID组雌性小鼠TG、TC、LDL水平(1.48±0.26)、(276±0.43)、(0.62±0.22)mmol/L]、MID组雌性小鼠LDL水平(0.60±0.17)mmol/L]均高于NI组(1.22±0.36)、(2.51±0.38)、(0.48±0.08)mmol/L,P均＜0.05].10HI和50HI组雄性小鼠TG水平(1.12±0.22)、(0.90±0.11)mmol/L]均低于NI组(P均＜0.05),10HI和50HI组雌性小鼠TC水平(2.35±0.34)、(2.37±0.37)mmol/L]、50HI组雌性小鼠LDL水平(0.65±0.18)mmol/L]均低于NI组(P均＜0.05).适钠组中的SID和MID组血清TT4(0.00±0.00)、(17.15±15.26)nmol/L]、FT4(0.93±0.42)、(18.46±4.31)pmol/L]和TT3(0.49±0.07)、(0.67±0.10)nmol/L]、FT3(2.86±0.37)、(3.18±0.24)pmol/L]水平均低于NI组(37.15±15.26)、(28.46±4.31)、(0.85±0.10)、(3.87±0.24)pmol/L,P＜0.01或P＜0.05].在低钠组,SID和MID组血清TT4、FT4和TT3、FT3水平(0.00±0.00)nmol/L、(1.03±0.78)pmol/L、(0.51±0.05)nmol/L,(3.01±0.17)pmol/L,(19.76±12.22)nmol/L、(21.46±5.37)pmol/L、(0.71±0.21)nmol/L、(3.56±0.23)pmol/L]均低于NI组(36.23±14.72)nmol/L、(30.96±6.33)pmol/L、(0.89±0.20)nmol/L、(4.05±0.24)pmol/L,P均＜0.05],10HI组的TT3水平(1.06±0.23)nmol/L]高于NI组(P＜0.05).结论碘缺乏可致TG、TC和LDL升高,过量碘可致TG/TC水平降低.碘摄入量是影响血脂代谢的重要因素.限盐饮食的同时,严密监控碘的摄入量对当前有效防治心血管疾病应具有重要作用.

The impact of dietary iodine/sodium intake on blood lipid metabolism in mice

Objective The present study has been designed to investigate the impact of dietary iodine/sodium intake on blood lipid metabolism in mice. Methods According to body weight and gender, two hundred and sixty Balb/c mice were randomly divided into 2 groups including normal sodium group(Na) and low sodium group(LNa), with 130 animals per group. Each group were then randomly further divided into 5 sub-groups according to the amount of iodine intake: ① severe iodine deficiency(SID); ② mild iodine deficiency(MID); (③normal iodine (NI); ④ 10-fold high iodine ( 10HI ); (⑤ 50-fold high iodine (50HI), 10 groups in total, 26 per group.Eight months later, the body weight and the levels of urinary iodine, thyroid hormones and total cholesterol (TC),Results In Na group, the levels of TG and TC in male mice of SID group (1.64 ± 0.35), (3.88 ± 0.35 )mmol/L]and MID group ( 1.67 ± 0.31 ), (3.41 ± 0.66)mmol/L] were significantly higher than that of NI group ( 1.49 ± 0.42), (3.25 ± 0.47)mmol/L] and the levels of TG in female mice of SID group(1.52 ± 0.22)mmol/L] were significantly higher than that of NI group (1.23 ± 0.22)mmol/L]. In addition, the levels of TG in male mice of 10HI and 50HI groups ( 1.16 ± 0.23 ), ( 1.21 ± 0.27 ) mmol/L ] were significantly lower than that of NI group ( 1.49 ± 0.42)mmol/L, all P ＜ 0.05], the levels of TC in female mice of 10HI and 50HI groups(2.37 ± 0.49), (2.48 ± 0.37)mmol/L] were significantly lower than that of NI group (2.84 ± 0.37) mmol/L, all P ＜ 0.05 ]. In LNa group,the levels of TG and TC in male mice of SID group (1.39 ± 0.40), (3.33 ± 0.46 )mmol/L] were significantly lower than that of NI group (1.30 ± 0.28), (3.00 ± 0.53) mmol/L, all P ＜ 0.05], the levels of TG, TC and LDL in female mice of SID group (1.48 ± 0.26), (2.76 ± 0.43), (0.62 ± 0.22)mmol/L], the levels of LDL in female mice of MID group (0.60 ± 0.17 )mmol/L] were significantly lower than that of NI group(l.22 ± 0.36), (2.51 ± 0.38),(0.48 ± 0.08), (0.48 ± 0.08)mmol/L, all P ＜ 0.05], the levels of TG in male mice of 10HI and 50HI group (1.12 ± 0.22), (0.90 ± 0.11 )mmol/L] were significantly lower than that of NI group (all P ＜ 0.05 ), the levels of TC in female mice of 10HI and 50HI groups (2.35 ± 0.34), (2.37 ± 0.37)mmol/L], the levels of LDL in female mice of 50HI group(0.65 ± 0.18)mmol/L], were significantly lower than that of NI group(all P ＜ 0.05). In Na group, the levels of thyroid hormones were distinctively decreased in SID groupTT4(0.00 ± 0.00)nmol/L, FT4 (0.93 ± 0.42)pmol/L, TT3(0.49 ± 0.07)nmol/L, FT3(2.86 ± 0.37)pmol/L] and MID group TT4 (17.15 ± 15.26)nmol/L, FT4( 18.46 ± 4.31 )pmol/L, TT3(0.67 ± 0. 10)nmol/L, FT3(3.18 ± 0.24)pmol/L] compared with that of the NI group TT4 (37.15 ± 15.26)nmol/L, FT4(28.46 ± 4.31)pmol/L, TT3(0.85 ± 0.10)pmol/L, FT3(3.87 ± 0.24)pmol/L, all P ＜ 0.05 ]. In LNa group, the levels of thyroid hormones were distinctively decreased in SID group TT4 (0.00 ± 0.00) nmol/L,FT4(1.03 ± 0.78)pmol/L, TT3(0.51 ± 0.05)nmol/L, FT3(3.01 ± 0.17)pmol/L] and MID groupTT4(19.76 ± 12.22)nmol/L, FT4(21.46 ± 5.37)pmol/L, TT3(0.71 ± 0.21)nmol/L, FT3(3.56 ± 0.23)pmol/L] compared with that of the NI groupTT4(36.23 ± 14.72)nmol/L, FT4(30.96 ± 6.33)pmol/L, TT3(0.89 ± 0.20)nmol/L, FT3(4.05 ± 0.24)pmol/L, all P ＜ 0.05]. Conclusions Dietary iodine intake plays an important role in the blood lipid metabolism. Iodine deficiency could increase while iodine excess could decrease the levels of serum TG, TC or LDL in mice. Monitoring the amount of iodine intake during sodium restriction should have an important role in effective prevention and treatment of cardiovascular disease.