EFFECTS OF ZINC ON THE EXPRESSION OF METALLOTHIONEIN ISOFORMS IN DIFFERENT BRAIN DOMAINS IN RATS UNDER STRESS / 营养学报

ABSTRACT

Objective: To explore the effects of different doses of Zn on the expression of metallo- thionein(MT) isoforms in hippocampus, olfactory bulb, diencephalon and cortex in stress rats. Method: The animal model of psychological stress was developed by restraint for 4w. Wistar rats were randomly assigned to 8 groups control group, Zn-deficient group, pair-fed group, Zn -supplemented group and their corresponding stress groups. The expressions of MTs and their mRNAs were detected by Western blot and RT-PCR respectively. Results: In Zn-deficient group, plasma zinc content was decreased, while in Zn -supplemented group slightly increased. Compared with Zn-deficient group, the stress Zn -deficient group had higher expressions of MTs and MT-1 mRNA, MT-3 mRNA in hippocampus, olfactory bulb, diencephalon and cortex. Expressions of MTs in Zn-supplemented group were increased, and much more in corresponding stress group. In addition, the levels of plasma cortisol, IL-6 and IL-1 were increased clearly in Zn-deficient group and stress groups. Moreover, MTs’ productions were different in four brain domains,the highest in hippocampus and the lowest in diencephalon. Conclusion: Zn may affect the expressions of MTs and MT-1 mRNA, MT-3 mRNA in different regions of brain in stress rats. The higher production of MTs in hippocampus may be related to its role in body’s adaptation to stress. Cortisol, IL-6 and IL-1 may be involved in the modulation of expression of MTs.