Effects of maternal and infant separation on Wnt signaling molecules in hippocampus of offspring rats

Abstract

Objective To determine the effects of maternal and infant separation(MS) on anxiety and depression-like behaviors, Wnt signaling molecules and receptors in the hippocampus of offspring rats. Methods Sixteen Sprague-Dawley (SD) pregnant rats (240~260 g) were randomly and equally divided into 2 groups. The offspring rats from the control group (CON) received no postpartum intervention, while those of the experiment group (MS) were given maternal-infant separation 3 h per day for 14 consecutive days since delivery. Elevated plus maze test (EPMT) and forced swimming test (FST) were conducted to evaluate the anxiety and depression-like behaviors of 1-month-old offspring rats. Real-time quantitative PCR was used to detect the levels of Wnt molecules in the hippocampus of the offspring rats, and Western blotting was adopted to determine the expression of Wnt2 and Wnt3a proteins as well as the Wnt signaling pathway inhibitory molecules DKK1 and sFRP3 in the hippocampus. Results The total number of arm entries (including open-arm and close-arm entries) was not statistically different between the MS and CON groups. However, the MS group had significantly lower percentages of open-arm entries (P < 0.01) and open-arm time (P < 0.05), and longer stationary time (P < 0.05) in the FST than the CON group, indicating obvious anxiety and depression-like behaviors. Moreover, the mRNA levels of Wnt2 and Wnt3a in the hippocampus were notably decreased (P < 0.01), while the protein levels of DKK1 and sFRP3 were increased remarkably (P < 0.01) in the MS group than the CON group. Conclusion Maternal and infant separation leads to depression and anxiety-like behaviors in offspring rats, which may be associated to the disorder of Wnt signaling molecules in the hippocampus.

Keywords

• maternal and infant separation
• wnt signaling molecules
• depression
• hippocampus
• inhibitors