The impact of dietary iodlne/sodium intake on blood Hpid metabolism in mice

Abstract

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 group[TT4（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 group[TT4（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 group[TT4（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. Key words: Iodine; Sodium; Lipid metabolism; Thyroid hormones