Effects of iodine and selenium depletion on growth and bone quality of rats
Abstract
Scope and Method of Study: This project investigated the effects of experimental Iodine (I) and/or selenium (Se) depletion on bone density, structure, and strength in young rats. Dams were fed experimental diets beginning at week 1 of lactation. Pups were weaned at 3 wks of age and a sub-sample of males and females were fed the experimental diet of their mother for an additional 7 wks. I and Se status and growth in the animals were assessed. Bones quality of the rats was investigated for biochemical markers of bone metabolism, bone density, structure, and strength. Oxidative status was also assessed. Findings: Weight gain was decreased by I depletion in all animals and by Se depletion in males. Thyroid weight was increased and serum thyroxine (T4) was reduced by I deficiency. Se depletion was confirmed by lower hepatic glutathione peroxidase activity. Tri-iodothyronine (T3) was higher in female rats when Se was deficient. I and Se depletion independently decreased bone length and mineral area (BMA) in tibia and femur and selenium depletion decreased femur cortical thickness. There was higher bone turnover and lipid oxidation, and lower bone ash weight in male rats. BMA and bone mineral density (BMD) in vertebra, and bone mineral content in tibia, femur and vertebra were decreased by Se depletion in male rats as measured by DEXA. Analysis of proximal tibia and L3 trabecular bone by micro-computed tomography (mCT) showed a better bone microacthitecture in females than males and when Se was adequate, the deficiency of I increased the structural quality of both tibia and L3 trabecular bone. Tibia cortical bone volume and thickness were higher in males when Se was adequate. The compressive strength of L3 trabecular bone and the bending strength of femur were better in females. The breaking force of femur was higher in iodine adequate rats when Se was also adequate, and the adequacy of iodine increased femur stiffness in females. Iodine and/or selenium depletion impaired bone quality in growing rats.
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- OSU Dissertations [11222]