Effect of dietary zinc deficiency on brain metallothionein-I and -III mRNAlevels during stress and inflammation

Zinc is an essential heavy metal for the normal function of the central ner vous system (CNS), but the knowledge of its metabolism and functions is sca rce. In this report we have studied the effect of a zinc deficient diet on the regulation of brain metallothioneins (MTs). In situ hybridization analy sis revealed that brain MT-I induction by restraint stress was significantl y blunted in some but not all brain areas in the mice fed the zinc deficien t diet compared to normally fed mice. In contrast, brain MT-I induction by the administration of bacterial lipopolysaccharide (LPS) was not significan tly lower in the mice fed the zinc deficient diet. In contrast to MT-I, MT- III mRNA levels were minimally affected by either stress or LPS. Yet, signi ficant decreasing effects of the zinc deficient diet were observed in areas such as the neocortex, CA1-CA3 neuronal layer and dentate gyrus of the hip pocampus, and the Purkinje neuronal layer of the cerebellum These results d emonstrate that dietary zinc deficiency impairs the response of brain MTs d uring both stress and LPS-elicited inflammatory response in a highly specif ic manner. (C) 2000 Elsevier Science Ltd. All rights reserved.