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Objective:To verify the determination method of iodine in serum by inductively coupled plasma mass spectrometry (ICP-MS) and to evaluate the consistency between ICP-MS and As 3+-Ce 4+ catalytic spectrophotometry in determination of serum iodine. Methods:Serum iodine concentration was determined by ICP-MS, 187Re was used as an internal standard, and ralated parameters were optimized. Eighty-eight serum samples were simultaneously determined by ICP-MS and As 3+-Ce 4+ catalytic spectrophotometry, and the evaluation indexes included determination range of standard curve, detection limit, precision, accuracy. In addition, we also evaluated the consistency of the two methods through inter-group correlation analysis, intra-group correlation coefficient analysis, Passing-Bablok regression and Bland-Altman analysis. Results:The linear range of ICP-MS standard curve was 0 - 300 μg/L. There was a good linear correlation between iodine concentration value and iodine response value, and the correlation coefficient range was 0.999 8 to 0.999 9. The detection limit of the ICP-MS method was 1.96 μg/L. The relative standard deviation ( RSD) ranged from 0.2% to 1.4% and from 0.4% to 1.8% for intra and inter-batch precision tests of serum samples. The recovery rate ranged from 90.44% to 108.71%. The correlation analysis of 88 serum samples showed that there was a good correlation between the two methods ( r = 0.934, P < 0.05), and the intra-class correlation coefficient was 0.932. The results of Passing-Bablok regression showed that there was no significant difference between the two methods ( P > 0.05). Bland-Altman diagram suggested that the results of the two methods were consistent. Conclusions:ICP-MS method has low detection limit, high precision and accuracy. ICP-MS method is simple, rapid, easy and suitable for determination of iodine in large quantities of serum samples. The results of the two methods for determining serum iodine are consistent.
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Objective To observe prolactin (PRL) and estradiol (E2) levels in lactating women in different iodine nutrition areas.Methods According to the recent national water-borne high iodine area survey and the monitoring results of iodine deficiency disorders,the following places were selected,including Nankang,Xinggang and Yingpan towns of Beihai City,Guangxi (water iodine ≤ 10 μg/L,low iodine areas),Yangcheng Township and Jiajiazhuang Township of Fenyang City,Shanxi (water iodine 50-100 μg/L,adaptive iodine areas),Pingyao County and Jicun Town of Fenyang City,Shanxi (water iodine ≥300 μg/L,high iodine areas),and urinary and blood samples were collected in lactating women (n =100,97,123) from the three regions.The urinary iodine concentration was tested by arsenic cerium catalytic spectrophotometry.Serum levels of PRL and E2 were determined by chemiluminescence immunoassay.Results The urinary iodine medians of lactating women were 51.42,283.62,842.31 μg/L,respectively,in the three regions,the difference between the regions was statistically significant (x2 =241.09,P ＜ 0.05);the iodine levels of lactating women in low iodine areas,adaptive iodine areas and high iodine areas were in the state of iodine deficiency (＜ 100 μg/L),sufficient or adequate (200-299 μg/L) and iodine excess status (≥ 300 μg/L),respectively.Serum PRL and E2 levels of lactating women in the three types of areas were 38.81,20.98,16.41 μg/L and 29.57,43.70,45.51 ng/L,respectively.The differences between the regions were statistically significant (x2 =41.54,24.03,P ＜ 0.05).Conclusion With the increase of iodine nutrition level,PRL in lactating women has presented a gradually decreasing trend,E2 is increased.
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Objective To observe the changes of sodium iodide symporter (NIS) in mammary gland of rats at different lactation periods,and to explore iodine uptake mechanism.Methods Seventy-five adult Wistar rats were selected,including 60 females,15 males,weighting 220-250 g.All female Wistar rats were divided into 4 groups according to their body mass via random number table method:normal non-pregnant group,lactating for 7-,14-and 21-day groups,15 rats in each group.All rats were fed with adequate conventional fodder and tap water.In addition to normal non-pregnant group,other three groups of female and male rats were mated at 3 ∶ 1,respectively,then after lactating for 7th,14th and 21th days,mammary gland tissues were harvested.The expressions of NIS mRNA and protein were measured with real time quantitative PCR (qRT-PCR) and immunohistochemical staining,respectively.Results NIS protein was expressed in the small ductal epithelium of mammary gland and the basal lateral membrane under light microscope,obvious brown particles visible.The expression of NIS mRNA (0.79 ± 0.11,1.05 ± 0.21,0.98 ± 0.18,0.89 ± 0.16) in mammary gland showed significant differences between groups (F =5.965,P ＜ 0.05),the expressions of NIS mRNA in 7th and 14th day groups were higher than that of normal non-pregnant group (P ＜ 0.05).The expression of NIS protein in mammary gland showed significant differences between groups (H =32.747,P ＜ 0.05),the staining intensity of mammary gland tissue after lactating for 7th,14th and 21th days groups was stronger than that of normal non-pregnant rats (P ＜ 0.05).Conclusions NIS is expressed in mammary gland of rats at different lactation periods.The iodine uptake of mammary gland is enhanced in early lactation period.
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Objective To observe the expressions of thyroid-stimulating hormone receptor (TSHR) protein and mRNA in thyroid gland of lactating rats.Methods Eighty adult Wistar rats (60 females and 20 males),weighting 210-250 g were selected.The 60 female Wistar rats were divided into 6 groups according to their body weight by means of random number table:normal non-pregnant group,lactating for 5,10,15 and 20 days groups and weaning for 5 days group,10 rats in each group.All rats were fed with conventional fodder and tap water freely,and the rats of lactating groups except the normal non-pregnant group cohabited with male rats (3 ∶ 1).Then all rats were killed on the 5th,10th,15th and 20th day after lactation and on the 5th day after weaning to get thyroid tissues.The expressions of TSHR protein and mRNA were determined by immunohistochemical staining and realtime quantitative PCR.Results TSHR protein was expressed in cytoplasm and membrane of rat thyroid follicular cells.The expression of TSHR protein in thyroid gland was significant different statistically between groups (x2 =11.227,P ＜ 0.05); the staining intensity of rat thyroid tissues in the normal non-pregnant gruop (weak,n =2; moderate,n =5; strong,n =3) was stronger than that of rats lactating for 5 days (weak,n =7; moderate,n =3; x2 =5.895,P ＜ 0.05).But the expression of TSHR protein in thyroid tissues in the normal non-pregnant group was not significantly different statistically compared with the expression of TSHR protein in other groups (lactating for 10,15and 20 days) and weaning for 5 days group (all P ＞ 0.05).The expression of TSHR mRNA in thyroid gland was significantly different statistically between groups (F =2.970,P ＜ 0.05); the expression of TSHR mRNA in lactating for 5 days group (0.74 ± 0.13) was lower than that of the non-pregnant group (1.02 ± 0.24,P ＜ 0.05); and the expression of TSHR mRNA in the normal non-pregnant group was not significantly different statistically compared with those of other groups (lactating for 10,15 and 20 days) and weaning for 5 days group (all P ＞ 0.05).Conclusion TSHR is widely expressed in thyroid gland of lactating rats,but relatively lower in early lactation period.
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Objective To observe the effects of insulin-like growth factor-Ⅰ (IGF-Ⅰ) and transforming growth factor-β1 (TGF-β1) on the expressions of sodium iodide symporter(NIS) and pendrin mRNA in a placental villous trophoblast cell line(HPT-8) exposed to different levels of iodine.Methods HPT-8 cells were cultured in vitro in the culture flask and divided into low iodine group-Ⅰ (LI-Ⅰ),low iodine group-Ⅱ (LI-Ⅱ),control group,high iodine group-Ⅰ (HI-Ⅰ) and high iodine group-Ⅱ (HI-Ⅱ) that exposed to different concentrations of iodine (0,5,50,500,5000 μg/L).After cell cultured for 24 h,the followings were added to the culture medium:iodine plus IGF-Ⅰ(0.050 mg/L),iodine plus TGF-β1 (0.001 mg/L).After cultured for another 24 h,total RNA was extracted,the expressions of NIS and pendrin mRNA of HPT-8 cells were determined by real-time quantitative PCR.Results The expression of NIS mRNA in HPT-8 cells:at different levels of iodine,the differences of NIS mRNA expression between groups were statistically significant in group with iodine alone(F =3.612,P ＜ 0.01).The expression of NIS mRNA in LI-Ⅰ group(0.44 ± 0.21) was significantly lower than that of control group(1.25 ± 0.77,P＜ 0.01).At the same level of iodine,in LI-Ⅰ group and HI-Ⅰ group,the differences of NIS mRNA expression within groups were statistically significant (F =13.632,6.900,all P ＜ 0.01).In LI-Ⅰ group,the expressions of NIS mRNA were higher in iodine plus IGF-Ⅰ(1.13 ± 0.38) and iodine plus TGF-β1 (0.81 ± 0.34) than that of pure iodine(0.44 ± 0.21,P ＜ 0.01 or ＜ 0.05);in HI-Ⅰ group,the expression of NIS mRNA was lower in iodine plus TGF-β1 (0.62 ± 0.30) than that of pure iodine(1.23 ± 0.91,P ＜ 0.01).The expression of pendrin mRNA in HPT-8 cells:at different levels of iodine,the differences of pendrin mRNA expression between groups were statistically significant in group with iodine alone(F =12.717,P ＜ 0.01).The expression of pendrin mRNA in LI-Ⅰ group(0.59 ± 0.15) was significantly lower than that of control group(1.03 ± 0.14,P ＜ 0.01) ; HI-Ⅰ group(1.29 ± 0.31) was higher than control group(P ＜ 0.05).At the same level of iodine,the differences of pendrin mRNA expression within groups were statistically significant in LI-Ⅰ,LI-Ⅱ,control and HI-Ⅰ groups (F=12.588,4.588,8.679,8.445,all P ＜ 0.01).In LI-Ⅰ,LI-Ⅱ and control groups,the expressions of pendrin mRNA were significantly higher in iodine plus IGF-Ⅰ(1.68 ± 0.82,1.51 ± 0.79,1.50 ± 0.51) than that of pure iodine(0.59 ± 0.15,0.89 ± 0.22,1.03 ± 0.14,all P ＜ 0.01); in HI-Ⅰ group,the expression of pendrin mRNA was significantly lower in iodine plus TGF-β1 (0.78 ± 0.20) than that of pure iodine(1.29 ± 0.31,P ＜ 0.01).Conclusions In the case of iodine deficiency,the mRNA expressions of NIS and pendrin in HPT-8 cells are decreased and the iodine uptake ability is decreased; the expression of pendrin mRNA in HPT-8 cells is increased and placental iodine uptake is increased under the conditions of mild iodine excessive.IGF-Ⅰ and TGF-β1 play a role in the placental iodine uptake through increasing iodine uptake under the conditions of iodine deficiency and decreasing iodine uptake under the conditions of iodine excessive.