A stereological analysis of the cerebellar granule and Purkinje cells of 30-day-old and adult rats undernourished during early postnatal life.

Male rats undernourished from birth to 30 days of age were nutritionally rehabilitated till 160 days of age. Quantitative stereological procedures at the light microscope level were used to estimate, among other things, the numerical densities of cerebellar granule and Purkinje cells on a "per unit volume of cortex" basis. These were subsequently used to calculate granule-to-Purkinje cell ratios. The 30-day-old undernourished rats had a mean +/- S.E. of 290 +/- 27 granule cells for every Purkinje cell present, compared to 395 +/- 34 for the controls. This was a deficit of about 27% (p < 0.05). At 160 days of age, the previously undernourished rats still showed a persisting deficit of about 25% (p < 0.05) in this ratio, despite the lengthy nutritional rehabilitation. There were no statistically significant age-related changes in this ratio. The numerical density of Purkinje cells, but not that of granule cells, was significantly greater in the previously undernourished rats than in controls, for both age groups, Increasing age caused a fall in the numerical density of both cell types. Granule and Purkinje cell nuclear diameters were unaffected by nutrition. However, Purkinje cell nuclei decreased in size by between 7%--13% with increasing age. These results indicate that undernutrition during early life can cause a permanent distortion of the relative number of the various cell types in the cerebellum.