Delayed Effects of Surgery during Early Pregnancy on Brain Development in OXYS Rats

The aim of the present work was to study the effects of stress induced by surgical interventions in early pregnancy on neuron density in the prefrontal cortex and hippocampal fields CA1 and CA3 and on neurogenesis in the dentate fascia of the hippocampus in the adult offspring of OXYS rats. Female OXTS rats were paired with fertile males of the same strain and, 96 h after detection of spermatozoids in vaginal smears, underwent a surgical procedure imitating embryo transplantation. The offspring of these females (OXYS-PS) were studied in comparison with intact OXYS and WAG rats aged five months. The density of pyramidal neurons in the prefrontal cortex of intact OXYS rats was significantly greater than that in rats of the WAG control strain. Neuron density in hippocampal field CA1 in intact OXYS rats was smaller, while that in field CA3 was greater, than that in WAG rats. No significant differences in the intensity of neurogenesis were seen between intact WAG and OXYS rats. In rats of the experimental group, OXYS-PS, the density of pyramidal neurons was lower in the prefrontal cortex and hippocampal field CA1 than in both control strains, while in field CA3 it was lower only in comparison with intact OXYS rats. In addition, rats of the OXYS-PS group showed a higher level of neurogenesis in the dentate gyrus of the hippocampus than both control strains.