Perinatal omega-3 polyunsaturated fatty acid supply modifies brain zinc homeostasis during adulthood.
Dietary omega-3 polyunsaturated fatty acid (PUFA) influences the expression of a number of genes in the brain. Zinc transporter (ZnT) 3 has been identified as a putative transporter of zinc into synaptic vesicles of neurons and is found in brain areas such as hippocampus and cortex. Neuronal zinc is involved in the formation of amyloid plaques, a major characteristic of Alzheimer's disease. The present study evaluated the influence of dietary omega-3 PUFA on the expression of the ZnT3 gene in the brains of adult male Sprague-Dawley rats. The rats were raised and/or maintained on a control (CON) diet that contained omega-3 PUFA or a diet deficient (DEF) in omega-3 PUFA. ZnT3 gene expression was analyzed by using real-time PCR, free zinc in brain tissue was determined by zinquin staining, and total zinc concentrations in plasma and cerebrospinal fluid were determined by atomic absorption spectrophotometry. Compared with CON-raised animals, DEF-raised animals had increased expression of ZnT3 in the brain that was associated with an increased level of free zinc in the hippocampus. In addition, compared with CON-raised animals, DEF-raised animals had decreased plasma zinc level. No difference in cerebrospinal fluid zinc level was observed. The results suggest that overexpression of ZnT3 due to a perinatal omega-3 PUFA deficiency caused abnormal zinc metabolism in the brain. Conceivably, the influence of dietary omega-3 PUFA on brain zinc metabolism could explain the observation made in population studies that the consumption of fish is associated with a reduced risk of dementia and Alzheimer's disease.
Jayasooriya
Anura P
AP
Howard Florey Institute of Experimental Physiology and Medicine, University of Melbourne, Melbourne, Victoria 3052, Australia.
Ackland
M Leigh
ML
Mathai
Michael L
ML
Sinclair
Andrew J
AJ
Weisinger
Harrison S
HS
Weisinger
Richard S
RS
Halver
John E
JE
Kitajka
Klára
K
Puskás
László G
LG
D000818:Animals; D001921:Brain / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D017931:DNA Primers; D015525:Fatty Acids, Omega-3 / Q000378:metabolism*; D005508:Food Deprivation; D005786:Gene Expression Regulation; D006706:Homeostasis / Q000502:physiology*; D015363:Quinolones; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013054:Spectrophotometry, Atomic; D014105:Tosyl Compounds; D015032:Zinc / Q000097:blood / Q000134:cerebrospinal fluid / Q000378:metabolism*
D002352:Carrier Proteins; D017931:DNA Primers; D015525:Fatty Acids, Omega-3; D015363:Quinolones; D014105:Tosyl Compounds; C017800:zinc-binding protein; D015032:Zinc; C084731:zinquin