A STEREOLOGICAL STUDY ON THE NUCLEAR VOLUME OF CEREBELLAR GRANULE CELLS IN AGING RATS

A morphometric study an age changes of rat cerebellar cortex (Cnrs I a nd Grits II) was carried out. The nuclear volume of the granule cells was estimated by means of two unbiased stereological methods: the nucl eator, which enabled the estimation of the number-weighted mean Volume ((V) over bar(N)), and the point-sampled intercepts method, allowing the determination of the volume-weighted mean volume ((V) over bar V-N ). These parameters enabled the estimation of the coefficient of varia tion of nuclear volume in the number-weighted distribution [CV(V-N)]. All parameters were determined in eight age groups (2, 6, 9, 12, 15, 1 8, 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, usi ng unbiased techniques, that the nucleus of granule cells of the cereb ellar cortex showed a significant decrease in its mean Volumes ((V) ov er bar(V)) with age, especially from 21 months onwards. Although CV(V- N) was not correlated with age, it was also demonstrated that these ce lls bear a considerable nuclear size pleomorphy that was maintained th roughout the age spectrum. (C) 1997 Elsevier Science Inc.