Iron and Postpartum Depression: A Preclinical Evaluation in Sprague-Dawley Rats

Abstract

Background: Postpartum depression (PPD) is a mood disorder that affects 10 - 20 % of women after child birth. It has been observed that gestational iron deficiency which affects mostly mothers and their infants causes a deficit in behavioural, cognitive and affective functions precipitating depressive symptoms in both mothers and their infants during the postpartum period. The present work examined the role of iron in depression during the postpartum period in animal models. Method: Female Sprague-Dawley rats (200-250 g) were crossed. Pregnant rats received iron (0.005 mgkg-1 – 8.0 mgkg-1) or fluoxetine (3 mgkg-1 – 30 mgkg-1) or desferrioxamine (50 mgkg-1) or vehicle throughout the period of gestation (21-23 days). During the postpartum period, mothers from all groups were taken through the open field test (OFT) on postnatal day (PND) 2, forced swim test (FST) from PND 3 to PND 16 and novelty-induced hypophagia (NIH) from PND 18 to PND 22 and sacrificed on PND 28 for histological examination of the brains. After weaning the litter were taken through OFT on PND 35, FST from PND 36 – to PND 49, NIH from PND 51 to PND 55 and sacrificed on PND 57 for histological examination of the brains. Results: Results showed that rats treated with iron chelator desferrioxamine and vehicle during gestation together with their litter had exhibited increased immobility scores in FST, increased latency scores with reduced feeding in NIH and a decreased number of neurons and dendritic branches in the cortex of the brain. These depression-related effects were attenuated by iron supplementation which caused decreased immobility scores in FST comparable to rats treated with fluoxetine, a clinically effective antidepressant. Iron treatment decreased latency scores with increased feeding in NIH. Iron treated rats and their litter had a higher number of neurons with dendritic connections in the cortex similar to the effects of fluoxetine which has been associated with proliferation of neurons. Conclusion: These results together suggest that, iron supplementation during gestation exerts an antidepressant-like effect on depressive behaviour in postpartum rats and their litter as well as attenuates the neuronal loss associated with depressive conditions.