REPEATED COURSES OF ANTENATAL CORTICOSTEROIDS HAVE ADVERSE EFFECTS ON ASPECTS OF BRAIN DEVELOPMENT IN NATURALLY-DELIVERED BABOON INFANTS

摘要

Repeated courses of antenatal steroids in women threatening preterm delivery have beneficial effects on lung maturation, but concern exists about the effects on the developing brain. We aimed to determine whether repeated courses of antenatal corticosteroids increased the risk of neuropathology compared to single courses or no treatment. Single course animals received antenatal steroids at 123dg (n=6). A second course was administered to the repeated course group at 137dg (n=7). Controls received no antenatal intervention (n=5). Baboons delivered naturally at term, after which necropsy was performed. Brains were assessed histologically for parameters of development and neuropathology. Body weights did not differ between the groups (p>0.05); neither did brain weight in relation to body weight. Density of glial fibrillary acidic protein-immunoreactive (IR) astrocytes in white matter was increased in the single (p<0.05) and repeated course (p<0.01) groups compared to controls. Density of myelin-basic protein-IR oligodendrocytes was reduced in the repeated course animals compared to both controls and single course groups (p<0.05); olig2-IR, which labels all cells in the oligodendrocyte lineage, showed no difference between groups. Repeated courses of antenatal corticosteroids have effects on myelination in the developing non-human primate brain which should be taken into account when determining a dosing regimen.