Effects Of Prenatal Exposure To Chlorpyrifos On Cytoarchitecture Of Hippocampus And Medial Prefrontal Cortex

Chlorpyrifos is an organophosphate pesticide, which widely applied in agriculture. Environment exposure to low doses chlorpyrifos can damage human health. Previous studies found that pregnancy or newborn exposure to CPF can lead to cognitive deficits in adulthood rat. Hippocampus and medial prefrontal cortex are two key brain regions regulating learning and memory and maybe used as the structure basis. This study aimed to reveal the cytoarchitecture of hippocampus and medial prefrontal cortex in adult rat with prenatal CPF exposure.5mg/kg/d of CPF was injected to dams during GD13-17, with same dose of DMSO as control. On PN20, the litters were divided into four groups according to sex and dosage:male CPF group, male control group, female CPF group, and female control group. On PN60, the brains were removed and fixed, continuous slices were cut. Slices in the hippocampus and the medial prefrontal cortex were and stained. Five sections of hippocampus and three sections of PrL and IL regions of medial prefrontal cortex were counted. Total cell number of CA1, CA3and DG of hippocampus and neurons and glial cells numbers of PrL and IL of medial prefrontal cortex were recorded.Our results showed that prenatal CPF exposure reduced cell number of CA1and DG regions in dorsal hippocampus of males, with cell density and apoptosis in morphology, while slightly decreased cell number in DG region of hippocampus of females. Our studies showed reduced neurons and glials in PrL and IL of medial prefrontal cortex, with unchanged cell morpholgy. Our results implied that the embryonic exposure5mg/kg/d CPF can caused architecture abnormals in brain sub-regions.