Type 2 Iodothyronine Deiodinase Activity and Expressions of MBP and Synapsin I in Brain of Young Rats with Iodine Deficiency and Excess / 环境与健康杂志

ABSTRACT

Objective To study the activity of type 2 Iodothyronine deiodinase(D2)and the expressions of myelin basic protein(MBP)and synapsinⅠin the brain tissue of young rats fed on a diet with different levels of iodine.Methods Wistar rats were fed on a diet with different doses of KIO_3 for 3 months and then mated randomly.The serum TH and the brain D2 activity were measured in 28 days old pups.The protein expressions of MBP and SynapsinⅠin their brains were determined by immunohistochemistry staining.Results Compared with normal iodine group(NI),the serum TH levels of low iodine group(LI) were lower,while those of iodine excess groups were gradually decreased with their increase of iodine intake,especially in 100-fold high iodine group(100 HI),TT_4 and FT_4 were significantly decreased(P0.05).The immunohistochemistry staining showed weakly positive reactivity of MBP in corpus callosum and stronger of synapsin I in hippocampus CA3 in LI group compared with NI. The similar alterations were also found in all iodine excess groups with their increase of iodine intake.But MBP reactivity was stronger in 100 HI rats than the LI ones.Conclusion Iodine deficiency and iodine excess can cause hypothyroidism in degrees in the young rats,more severe hypothyroid and retarded myelin sheath and synapses can be caused in iodine deficiency compared with iodine excess.