EFFECTS OF SELENIUM AND IODINE DEPLETION/REPLETION ON BEHAVIORS OF ADULT C57BL/6 MICE

Li J.¹,2, Peters J.P.¹, Houbeau G.¹, Bister J.L.³, Rivera M.T.⁴, Vanderpas J.1,⁴, Huynen M.C.⁵, Wolff F.⁶, Mercier M.¹

¹Departments of Psychology, ³Laboratory of Animal Physiology, ⁴Unit of Epidemiology, University of Namur, Namur, Belgium, ²Department of Radiation Medicine, Faculty of Preventive Medicine, The Fourth Military Medical University, Xi’an, P.R.China, ⁵Behavioural Biology Unit, Department of Environmental Sciences, Institute of Zoology, University of Liege, 22 Quai Van Beneden, Liege, Belgium, ⁶Department of Chemistry, University Hospital Brugmann, Brussels, Belgium

Abstract

Objectives: Effects of selenium and iodine depletion and repletion on behaviors in adult mice.
Methods: Fifty-day-old (Day0) male C57BL/6 mice (n=48) were randomly divided into four groups: Se-I+, Se+I-, Se+I+ and Se-I. Diets were supplied from Day0 until Day160 (Depletion), thereafter 1% PTU (Propylthiouracyle) + 30% sucrose were given to Se+I- and Se-I- groups for 140 days to induce hypothyroidism (Depletion+PTU). From Day300 to Day365 (Repletion), all diets were changed to Se+I+, and PTU was removed. Open field test (OFT), bodyweight, food-intake, plasma T4 and GPx (Glutathione peroxidase) were tested during the three phases.
Results: T4 concentrations were in a hypothyroid range in Se+I- and Se-I- groups during Depletion+PTU, and euthyroid state was recovered during Repletion. GPx activities in Se-I+ and Se-I- groups were similar, significantly 300 times lower than in Se+I+ and 600 times lower than in Se+I- group during Depletion+PTU (also significant difference between Se+I+ and Se+I- groups); there was no more significant differences between the four groups during Repletion. In comparison with Se+I+ group, total distances of spontaneous locomotor activity in 5-minute-OFT of the other three groups were significantly reduced during Depletion+PTU (mean±SEM: Se-I+: 1000.9±210.6 cm; Se+I-: 1130.7±118.1 cm; Se+I+: 1723.9±207.5 cm; Se-I-: 787.6±103.2 cm, each n=12), but were similar with group Se+I+ during both Depletion and Repletion. Significant bodyweight loss with the lowest value in Se-I- was found in the three deficient groups, and was partially recovered after Repletion.
Conclusions: A 10-months selenium and/or iodine deficiency – with addition of PTU during the last 20 weeks to accentuate hypothyroidism – decreases neurobehaviors (spontaneous locomotor activity) in adult mice, and it is recoverable after reintroduction of normal diet. This neurobehavioral change was similar in Se-I+ and Se+I- mice, with less evidence of Se/I interaction. Both micronutrient deficiencies involve a weight loss – despite controlled food intake.