Resumo

Iron is an essential micronutrient involved in a variety of physiological processes, participating in myelination and as cofactor of enzymes involved in neurotransmitter synthesis such as tryptophan and tyrosine hydroxylases. Its deficiency is a worldwide public health issue. When iron deficiency (ID) occurs from the last trimester of pregnancy up to the age of 2 years, it alters brain and body growth. The main CNS areas affected by ID are the striatum, nucleus accumbens, hippocampus, frontal cortex and substantia nigra. These structures are involved in cognitive and emotional processes, of which the main alterations observed in people with ID are irritability, anxiety, depression and impaired long and short term memory. Although it has been reported that if ID is not reversed during vulnerable periods the alterations may become irreversible this is still under debate. In order to study these changes it is necessary to use a validated behavioral model of ID which is not yet available. Objective: To study behaviors related to ID in an animal model of dietary iron restriction and contribute to the development of a validated behavioral animal model of iron restriction. Methods: The offspring from Wistar rat mothers fed an ID (10 ppm) or an iron replete (100 ppm) diet were tested post-weaning at the age of 30 days, a period equivalent to human childhood. Working memory (short term), anxiety and depression were tested in the Morris water maze, open field and forced swim tests, respectively. We used an unpaired t test to evaluate the results (p <0.05). Results: No statistical differences were found between C vs ID groups in working memory. The anxiety (C vs ID) variables assessed -i.e., frequency of entries to the center (6.67 vs. 9.54 sec, p=0.05), latency in the center (21.33 vs. 64.15 sec, p=0.006) and on the periphery of the apparatus (151.78 vs. 106.31 sec, p=0.003)-, indicated that ID subjects presented a greater degree of anxiety. In the forced swim test, ID rats, presented longer immobility periods (13.25 vs. 34.17 sec, p=0.007), indicating a condition of despair or depression. Conclusions: The working memory, anxiety and depression results obtained are useful to validate an animal model of nutritional ID. This replicates related behaviors in ID humans, however no alterations in working memory were found. This may be due to the age at which the study was conducted in rats, an aspect which should be further investigated. Anxiety and depression however were present at this age under ID.