Effect of early-life maternal deprivation on depressive-like behavior and neurogenesis in hippocampal granular layer of adolescent rat / 中华行为医学与脑科学杂志

ABSTRACT

Objective:To explore the effects of early-life maternal deprivation on depressive-like behavior and neurogenesis in the granular layer of hippocampus in adolescent rats (6-7 weeks old).Methods:Neonatal rats were randomly divided into maternal deprivation group and control group, with 3 litters in each group.Rats in the maternal deprivation group were given maternal deprivation from 1 to 14 days after birth and rats in the control group were caged with the mother rats and raised normally.The body weight of rats at 5-6 weeks old was recorded and the increased body weight was calculated.When the rats were 6 weeks old, the sucrose preference test was carried out.Then the rats were killed and immunofluorescence histochemistry was applied to compare the expression of Ki67 and Nestin positive cells in the dentate gyrus of hippocampus.SPSS 22.0 software was used for statistical analysis.The data of the two groups were tested to conform to the normal distribution, and then t-test was carried out. Results:There was significant difference in body weight growth between the two groups at the age of 5-6 weeks.Compared with the control group, rats in the maternal deprivation group had lower body weight growth ((20.57±2.19) g, (30.57±1.25) g, t=3.96, P<0.01)) and lower sucrose preference rate((58.38±53.14)%, (73.88±3.67)%, t=3.21, P<0.01). The results of immunofluorescence showed that the number of Ki67 positive cells in the granular layer of hippocampus in the maternal deprivation group was less than that in the control group ((5.13±0.31), (7.60±0.38), t=5.09, P<0.01), and the number of Nestin immunofluorescence positive cells was more than that in the control group ((16.65±0.79), (7.64±0.70), t=8.51, P<0.01). The Nestin immunofluorescence positive cells in the maternal deprivation group had more protrusions and branches, and the morphology was similar to astrocytes, while the immunofluorescence positive cells in the control group had fewer protrusions, and the cell body was oval. Conclusions:Early-life maternal deprivation leads to depressive-like behavior in adolescent rats, which may be associated with the decrease of neurogenesis and activation of astrocytes in the dentate gyrus of the hippocampus.