Effect of maternal excessive iodine intake on neurodevelopment and cognitive function in rat offspring

<p>Abstract</p> <p>Background</p> <p>Iodine deficiency and iodine excess are both associated with adverse health consequences. Iodine deficiency during pregnancy leads to insufficient maternal thyroid hormone, subsequently causing irreversible adverse effects on the neu...

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Main Authors: Zhang Le, Teng Weiping, Liu Yuhui, Li Jing, Mao Jinyuan, Fan Chenling, Wang Hong, Zhang Hongmei, Shan Zhongyan
Format: Article
Language:English
Published: BMC 2012-10-01
Series:BMC Neuroscience
Subjects:
Online Access:http://www.biomedcentral.com/1471-2202/13/121
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author Zhang Le
Teng Weiping
Liu Yuhui
Li Jing
Mao Jinyuan
Fan Chenling
Wang Hong
Zhang Hongmei
Shan Zhongyan
author_facet Zhang Le
Teng Weiping
Liu Yuhui
Li Jing
Mao Jinyuan
Fan Chenling
Wang Hong
Zhang Hongmei
Shan Zhongyan
author_sort Zhang Le
collection DOAJ
description <p>Abstract</p> <p>Background</p> <p>Iodine deficiency and iodine excess are both associated with adverse health consequences. Iodine deficiency during pregnancy leads to insufficient maternal thyroid hormone, subsequently causing irreversible adverse effects on the neurological and cognitive functions of the offspring. The results of our previous epidemiological study suggested that mild iodine excess might increase the prevalence of subclinical hypothyroidism. In the present study, female Wistar rats maintained on low-iodine grain were randomly assigned to three groups based on iodated water concentration: low iodine (LI, 1.2 μg/d), normal iodine (NI, 5–6 μg/d), and 3-fold high iodine (3HI, 15–16 μg/d). The present study investigated whether higher-than-normal iodine intake (3HI) by rats from before pregnancy until breastfeeding affects the postnatal (PN) neurodevelopment (PN7 and PN45) of their offspring during particularly sensitive periods in brain development.</p> <p>Results</p> <p>After 12 weeks of treatment (before pregnancy), iodine concentrations in urine and thyroid tissue and circulating thyroxine of adult females correlated with iodine intake. Brain-derived neurotrophic factor (BDNF) expression in the hippocampi of pups on PN7 and PN45 was decreased in 3HI group compared to the NI controls (<it>P <</it> 0.05, all) On PN7 and PN45, the BDNF levels of the 3HI pups were 83.5% and 88.8%, respectively, that of the NI pups. In addition, the 3HI group had a higher neuroendocrine-specific protein A (NSP-A) level than the NI controls on PN7 (<it>P <</it> 0.05). NSP-A levels of the 3HI pups were 117.0% that of the NI pups. No significant difference was observed in the expressions of c-Fos or c-Jun in the hippocampal CA1 region of the 3HI group compared to the controls (<it>P ></it> 0.05). Results from the Morris water maze test revealed that pups of the 3HI group had mild learning and spatial memory deficits.</p> <p>Conclusions</p> <p>The neurodevelopmental and cognitive deficits of the 3HI pups were mild and temporary, likely related to the changes in hippocampal protein expressions of BDNF and NSP-A.</p>
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spelling doaj.art-b5243c7eeebf485bab802ceabfa34b632022-12-22T03:28:57ZengBMCBMC Neuroscience1471-22022012-10-0113112110.1186/1471-2202-13-121Effect of maternal excessive iodine intake on neurodevelopment and cognitive function in rat offspringZhang LeTeng WeipingLiu YuhuiLi JingMao JinyuanFan ChenlingWang HongZhang HongmeiShan Zhongyan<p>Abstract</p> <p>Background</p> <p>Iodine deficiency and iodine excess are both associated with adverse health consequences. Iodine deficiency during pregnancy leads to insufficient maternal thyroid hormone, subsequently causing irreversible adverse effects on the neurological and cognitive functions of the offspring. The results of our previous epidemiological study suggested that mild iodine excess might increase the prevalence of subclinical hypothyroidism. In the present study, female Wistar rats maintained on low-iodine grain were randomly assigned to three groups based on iodated water concentration: low iodine (LI, 1.2 μg/d), normal iodine (NI, 5–6 μg/d), and 3-fold high iodine (3HI, 15–16 μg/d). The present study investigated whether higher-than-normal iodine intake (3HI) by rats from before pregnancy until breastfeeding affects the postnatal (PN) neurodevelopment (PN7 and PN45) of their offspring during particularly sensitive periods in brain development.</p> <p>Results</p> <p>After 12 weeks of treatment (before pregnancy), iodine concentrations in urine and thyroid tissue and circulating thyroxine of adult females correlated with iodine intake. Brain-derived neurotrophic factor (BDNF) expression in the hippocampi of pups on PN7 and PN45 was decreased in 3HI group compared to the NI controls (<it>P <</it> 0.05, all) On PN7 and PN45, the BDNF levels of the 3HI pups were 83.5% and 88.8%, respectively, that of the NI pups. In addition, the 3HI group had a higher neuroendocrine-specific protein A (NSP-A) level than the NI controls on PN7 (<it>P <</it> 0.05). NSP-A levels of the 3HI pups were 117.0% that of the NI pups. No significant difference was observed in the expressions of c-Fos or c-Jun in the hippocampal CA1 region of the 3HI group compared to the controls (<it>P ></it> 0.05). Results from the Morris water maze test revealed that pups of the 3HI group had mild learning and spatial memory deficits.</p> <p>Conclusions</p> <p>The neurodevelopmental and cognitive deficits of the 3HI pups were mild and temporary, likely related to the changes in hippocampal protein expressions of BDNF and NSP-A.</p>http://www.biomedcentral.com/1471-2202/13/121Iodine deficiencyIodine excessThyroid hormoneHippocampusNeurodevelopment
spellingShingle Zhang Le
Teng Weiping
Liu Yuhui
Li Jing
Mao Jinyuan
Fan Chenling
Wang Hong
Zhang Hongmei
Shan Zhongyan
Effect of maternal excessive iodine intake on neurodevelopment and cognitive function in rat offspring
BMC Neuroscience
Iodine deficiency
Iodine excess
Thyroid hormone
Hippocampus
Neurodevelopment
title Effect of maternal excessive iodine intake on neurodevelopment and cognitive function in rat offspring
title_full Effect of maternal excessive iodine intake on neurodevelopment and cognitive function in rat offspring
title_fullStr Effect of maternal excessive iodine intake on neurodevelopment and cognitive function in rat offspring
title_full_unstemmed Effect of maternal excessive iodine intake on neurodevelopment and cognitive function in rat offspring
title_short Effect of maternal excessive iodine intake on neurodevelopment and cognitive function in rat offspring
title_sort effect of maternal excessive iodine intake on neurodevelopment and cognitive function in rat offspring
topic Iodine deficiency
Iodine excess
Thyroid hormone
Hippocampus
Neurodevelopment
url http://www.biomedcentral.com/1471-2202/13/121
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