Abstract: In order to study the effect of restraint stress on the neuroplasticity of pregnant sows, 6 Bama miniature sows aged 8-9 months were randomly divided into two groups:stress group (n=3) and control group (n=3). The remaining conditions were consistent.The pregnant pigs were sacrificed on the 18th day of gestation. The hippocampal and blood samples were collected and the hormone levels were detected by ELISA and radioimmunoassay.After the paraffin-embedded hippocampal sections were prepared and stained by Nishner staining and silver staining, the neuron loss rate, dendritic complexity and the number of dendritic spines were observed, and the expression level of brain-derived neurotrophic factor (BDNF) in the hippocampus was detected by Western blot. The results showed that the plasma levels of corticotropin-releasing hormone (CRH), adrenocorticotrophic (ACTH) and cortisol (COR) increased significantly in the stress group (P ≤ 0.05), in the hippocampus dentate gyrus (DG) and CA3 area neurons leakage phenomenon, CA3 area down cone cells dendritic complexity, mature dendritic spines of neurons and the quantity of immature dendritic spines are significantly reduced, DG mature dendritic spines significantly reduced, and the amount of BDNF protein expression in hippocampus was reduced by 70.6% (P ≤ 0.01). Therefore, restraint stress attenuates the neuronal plasticity of CA3 and DG in the hippocampus of pregnant pigs.

Key words: immobilization stress, pregnant pig, the hippocampus, neuronal plasticity