Study on the Effect of Different Iodine Intake on Hippocampal Metabolism in Offspring Rats

Abstract

Iodine is an essential trace element in the human body. Severe maternal iodine deficiency during pregnancy leads to obvious intellectual disability in the offspring. The effects of iodine deficiency on brain development have been demonstrated, but there is no clear evidence of the effects of iodine excess on brain development. To clarify the effects of iodine excess on the brain development of offspring and to provide clues to the mechanisms underlying the effects of iodine deficiency and iodine excess on the brain development of offspring. In this study, animal models with different iodine intakes were constructed using potassium iodate (KIO₃). The models included four experimental groups (low-iodine group one (LI, 0μg/L iodine), low-iodine group two (LII, 5μg/L iodine), high-iodine group one (HI, 3000μg/L iodine), and high-iodine group two (HII, 10000μg/L iodine)) and one control group (NI, 100μg/L iodine). There were 20 female rats in each group, and 8 offspring were chosen from each group following birth to assess metabolic alterations. The metabolites of subsets of brain hippocampal tissue were profiled by ultra-performance liquid chromatography-linked electrospray ionization quadrupole time-of-flight mass spectrometry (UPLC-ESI-QTOFMS) and the results were subjected to multivariate data analysis. Differential substances were screened by t test (p<0.05), principal component analysis (PCA), and partial least squares analysis (PLS-DA, VIP>1). The thyroid function of the female rats in the experimental group was abnormally changed. Metabolic analysis showed that the five groups were separated which revealed significant differences in hippocampal tissue metabolism among the five groups of offspring. A total of 12 potential metabolites were identified, with the majority of them being related to amino acid and energy metabolism. These metabolites are involved in various metabolic pathways, are interrelated, and may play a function in brain development. Our study highlights changes in metabolites and metabolic pathways in the brain hippocampus of offspring rats with different iodine intakes compared to controls, revealing new insights into hippocampal metabolism in offspring rats and new relevant targets.

Keywords: Hippocampus; Iodine deficiency; Iodine excess; Metabolomics; Offspring brain development.