Effects of undernutrition on gliogenesis and glial maturation in rat corpus callosum

Rats were undernourished by halving the mother's food intake from the sixth day of pregnancy onwards and through lactation. At weaning, the young rats were restricted to half the normal weight of food. A combination of light and electron microscopic techniques was used to study the effects of this regime on gliogenesis and glial maturation in the corpus callosum of animals aged between 15 and 48 days. A disturbance of neuroglial proliferation was suggested by the finding of an increased proportion of astroglia relative to oligodendroglia in the 15-day-old undernourished rats, indicating a delay in the acquisition of cells produced relatively late in development. Impaired differentiation of oligodendroglia was suggested by the finding in treated animals of increased light oligodendrocytes at 15 days and a deficit of dark oligodendrocytes at 48 days, relative to controls. The previously observed retardation in myelin acquisition seems thus to be related to a delay in the differentiation of oligodendroglia, although it seems likely that the proliferation of these cells is also disturbed in undernutrition.