Effects of magnesium oxide nanoparticles on memory impairment induced by postpartum depression model

Introduction: Plasma magnesium level is reduced after postpartum depression in female and this reduction can cause memory impairment. As regards the magnesium has antidepressant activity and it's deficiency leads to depression, the aim of this study was evaluating the effect of magnesium in form of magnesium oxide nanoparticles (MgO NPs) on memory retrieval in a postpartum depression model. Methods: Adult female mice (27±3g) were divided into groups of control, depressed and depressed recipient of MgO NPs (1, 2.5, 5 or 10mg/kg) as an acute and chronic administrations. For induction of postpartum depression, chronic administration (5 days) of progesterone was used and three days after stopping administration, the depressive behavior was evaluated by tail suspension test. Passive avoidance memory and locomotor activity have done 24 hours after training using the step-down and open field devices, respectively. Results: Induction of postpartum depression model by the withdrawal of progesterone significantly decreased the memory retrieval. Acute administration of MgO NP significantly improved depression and memory impairment in a dose-dependent manner, while chronic administration showed less improvement in depression and memory. There was no difference between locomotor activities in all groups. Conclusion: It seems that acute administration of MgO NPs could be more suitable supplement than its chronic ones for improving depression and prevent memory impairment induced by postpartum depression. Probably the duration of nanoparticles administration can be a determining factor in their efficacy.