Relation between RNA content and ageing in neurons of the dorsal lateral geniculate nucleus

We carried out a study to establish ribonucleic acid (RNA) content in the nucleus and cytoplasm of single neuronal cells from the dorsal lateral geniculate nucleus (dLGN) of 3-30 month-old rats. Mean RNA content was calculated as the product of RNA concentration and nuclear or cytoplasmic surface. The analysis of neuronal nuclei revealed no significant differences in RNA concentration, nuclear area, and RNA content from 3-18 months. However, a significant decrease in RNA concentration (18.73%) was found from the 18th-24th month, although no changes were observed in nuclear area and RNA content. The oldest rats, 24-30 months old, presented a significant increase in nuclear area and RNA content. As regards to the neuronal cytoplasm, no significant differences were found in any of the parameters at the ages from 3-18 months and 18-24 months. In contrast, a significant increase in RNA concentration (26.26%), cytoplasm area (18%), and RNA content (52%) takes place from the 24th-30th month. The increase in RNA content could be related to neuronal hypertrophy.