BDNF deletion can induce depression-related behaviors in postpartum only, but not in virgin female mice, which suggests the specific role of Bdnf in mPFC on PPD. A recent study showed that T cell death-associated gene 51 (TDAG51) knockout, microglia-specific autophagy-deficient mice combined with chronic unpredictable mild stress during gestation also can induce depression-related behaviors in the female mice after parturition also support the fact that certain functional genes indeed can affect the behaviors in the postpartum female mice [12, 50]. The Bdnf gene contains multiple promotor-specific exon mRNAs [10] to encode exactly the same protein. Our results indicated that exon I, II, and VI were down-regulated by CUS, which is in contrast to previous reports that chronic social defeat stress reduces exon IV and VI expression in the hippocampus of male mice [51]. This suggests a different and complex modulation of BDNF-specific promoters in female and male subjects with depression, however, the particular modifications of these promoters activity needs further investigation.
