The effects of intrauterine growth retardation (IUGR) on brain histological or functional development were examined in rats. IUGR was induced by ligating the bilateral uterine arteries at day 17 of pregnancy. On day 22 of pregnancy, cesarean section was performed, and pups with a birth weight of <2 SD of the mean birth weight of control pups were regarded as IUGR rats. Morphological changes of the brain were studied by Nissl's staining at different timepoints during prenatal and postnatal periods. For behavioral study, an open-field test was performed at 5, 7 and 10 weeks after birth. Histological studies showed the migration disorder of the neurons in the cerebral cortex from embryonic day 17 to postnatal day (PD) 49. The open-field test revealed locomotor disturbance at PD49 in male IUGR rats, but not in female IUGR rats or control rats. It is concluded that IUGR due to antenatal ischemia-hypoxia causes morphological changes in the central nervous system, and induces behavioral impairment, particularly in male rats.
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