A Stereological Study on the Nuclear Volume of Cerebellar Granule Cells in Aging Rats

Abstract A morphometric study on age changes of rat cerebellar cortex ( Crus I and Crus II) was carried out. The nuclear volume of the granule cells was estimated by means of two unbiased stereological methods: the nucleator, which enabled the estimation of the number-weighted mean volume (V N ), and the point-sampled intercepts method, allowing the determination of the volume-weighted mean volume (V V ). These parameters enabled the estimation of the coefficient of variation of nuclear volume in the number-weighted distribution [CV(V N )]. All parameters were determined in eight age groups (2, 6, 9, 12, 15, 18, 21, and 24 months—five animals per age) and the mean values of each age group were compared using one-way ANOVA with post hoc comparisons, and regression analysis. It was demonstrated for the first time, using unbiased techniques, that the nucleus of granule cells of the cerebellar cortex showed a significant decrease in its mean volumes (V V ) with age, especially from 21 months onwards. Although CV(V N ) was not correlated with age, it was also demonstrated that these cells bear a considerable nuclear size pleomorphy that was maintained throughout the age spectrum.