The impact of dietary iodine intake on lipid metabolism in experimental hypothyroid mice / 中国地方病学杂志

ABSTRACT

Objective To observe the effects of iodine deficiency and iodine excess on the lipid metabolism in an experimental hypothyroid model of mice and to explore the roles of iodine independent of its role in thyroid hormones. Methods Female Balb/c mice were randomly divided into 6 groups control, severe iodine deficiency (SID), mild iodine deficiency(MID), normal iodine (NI), 10-fold high iodine (10HI) and 50-fold high iodine(50HI), 10 in each group. The mice in control group were fed with low iodine forage, other mice were fed with low iodine forage containing 0.2% methylthiouracilum. All mice drank deionic water containing different concentrations of potassium iodide(KI). The iodine content in water was 326.79, 0, 196.08,326.79, 385621, 19 542.50 μg/L, respectively. After three months, thyroid hormones in the serum were determined by radioimmunoassay.Also, the blood samples were analyzed for total cholesterol (TC), triglyceride (TG), high density lipoprotein cholesteiol (HDL-C) and low density lipoprotein cholesterol (LDL-C) and measured enzymatically by automatic analyzer. Results①The levels of Tr4 in SID[(21.27 ± 9.63)μg/L], MID[(23.41 ± 3.93)μg/L], NI[(22.57 ±4.66)μg/L], 10HI [(21.07 ± 5.03) μg/L] and 50HI groups [(21.46 ± 5.90) μg/L] were distinctively decreased compared with control group[(42.15 ± 8.26)μg/L, all P ＜ 0.01]. There were no statistical significant differences of TT3 between different groups (F = 0.99, P > 0.05 ). ②The level of TG in 10HI group [ ( 1.17 ± 0.16)mmol/L ] was obviously decreased compared with control [(1.39 ± 0.22 )mmol/L] and NI groups[(151 ± 0.22)mmol/L, all P＜ 0.05].Both TG and TC in 50HI group[(1.18 ± 0.22), (1.78 ± 0.15)mmol/L] were significantly decreased compared with control [( 1.39 ± 0.22), (2.14 ± 0.37)mmol/L] and NI groups [(1.51 ± 0.22), (2.00 ± 0.15)mmol/L, all P ＜ 0.05].The difference of serum HDL-C and LDL-C between the groups was not significant(F = 0.55,0.54, all P ＞ 0.05 ).Conclusions Dietary iodine plays a role in the metabolism of serum lipids independent of thyroid hormones.Thus, monitoring the amount of iodine intake during sodium restriction should also be taken extremely important for effectively prevention and cure of cardiovascular disease.