Volumetric investigation of the hippocampus in rat offspring due to diabetes in pregnancy-A stereological study.

BACKGROUND: The brain development during the prenatal period is affected by various factors, including the mother's metabolic condition. It has been revealed that diabetes in pregnancy is associated with structural and functional alterations in offspring's hippocampus. Hippocampus, as a critical region with well-known roles in learning and memory consolidation, is vulnerable to changes in glucose level. This study was designed to investigate the effects of maternal diabetes during the pregnancy period and insulin therapy on the neuronal density and the volume of different subfields of the hippocampus in rat offspring at postnatal day 14 (P14). METHODS: Wistar female rats were randomly divided into diabetics (STZ-D), diabetes treated with insulin (STZ-INS) group, and controls (CON). The animals in all groups were mated by non-diabetic male rats. Two weeks after birth, male pups from each group were sacrificed. The Cavalieri method was carried out to estimate the total volume, and the numerical density of the neurons in the hippocampus and its sub regions was measured by the optical dissector technique. RESULTS: Bilateral hippocampal volume decreased in the diabetic group, mainly in the CA1, dentate gyrus (DG) and subiculum areas (P ≤ 0.05), when compared to control and insulin-treated diabetic animals. In all hippocampus sub-regions, maternal diabetes resulted in a significant decrease in the number of cells in comparison with two other groups (P ≤ 0.05 each). CONCLUSION: These data indicate that diabetes during pregnancy has a negative impact on the development of the hippocampus in the rats. These changes in the volume of hippocampal CA1, DG, and subiculum areas might be at the core of underlying neurocognitive and neurobehavioral impairments observed in the children of diabetic mothers.