QUANTITATIVE MORPHOLOGICAL-CHANGES IN NEURONS FROM THE DORSAL LATERALGENICULATE-NUCLEUS OF YOUNG AND OLD RATS

Background: We studied the morphological changes occurring in neurons from the dorsal lateral geniculate nucleus (dLGN) during aging by anal ysing the size and shape of cell bodies and nuclei, Methods: Male albi no Wistar rats, aged 3, 18, 24, and 30 months, were used, After approp riate tissue preparation and following the usual histological procedur e, the profiles of 1,920 neuronal bodies and nuclei were drawn using a camera lucida, Data was later recorded and processed with a semiautom atic image analyser. Results and conclusions: We observed that dLGN ne urons do not change in size from the age of 3-24 months, Between 24 an d 30 months, the soma and nucleus of the cell undergo hypertrophy, 32. 8% and 35.6%, respectively, when compared to those from 3-month-old an imals (P < 0.01), Furthermore, we found a high correlation between cel l body size/nucleus size, which does not disappear with age, The r val ues (correlation coefficient) were 0.7998, 0.8662, 0.8433 and 0.7304, and R-2 (determination coefficient) was equal to 0.6397, 0.7504, 0.711 2, and 0.5335, These latter values show that in 63.97%, 75.04%, 71.12% , and 53.35% of cases, respectively, modifications in somata size were accompanied by similar changes in nucleus size, and vice-versa. The s tudy of the shape of the soma and nucleus of the cell revealed that bo th structures have a rounded-oval configuration that does not change i n a significant way from adulthood to old age. (C) 1997 Wiley-Liss, In c.