Inhibition of expression of glucocorticoids receptors may contribute to postpartum depression

Although postpartum depression (PPD) is the leading cause of disability worldwide, its molecular mechanisms are poorly understood. Recent evidence has suggested that impaired glucocorticoid receptor (GR), the signaling of key molecules of the HPA axis, plays a key role in the behavioral and neuroendorcrine alterations of major depression. However, the role of GR in postpartum period, which following with the abrupt withdrawal of placental corticotropin releasing hormone (CRH) and resulting in a re-equilibration of the maternal HPA axis in the days of post-delivery, is still not entirely clear. Previously, a hormone-simulated pregnancy (HSP), and the subsequent 'postpartum' withdrawal in estrogen has been employed to mimic the fluctuations in estradiol associated with pregnancy and postpartum. Using the HSP model, we investigated here the effect of 'postpartum' withdrawal in estrogen as well as depression- and anxiety-like behavior by intra-hippocampal infusion with GR inhibitor-RU486. Following the successful acquisition of PPD model by withdrawal in estrogen, reduced GR expression was observed in hippocampus. Further, HSP-rats suffered intra-hippocampal RU486 infusion presented depression- and anxiety-like behavior as postpartum depression. Together, these results suggest an important, though complex, role for GR in the behavioral regulation of postpartum depression.