Age-related changes in rat retina

Purpose: To describe the changes in rat retina occurring with ageing by mea ns of histological methods, scanning electron microscopic observations and morphometrical data; and to study by means of biochemical methods the amoun t of protein content in retinal tissues. Methods: Samples of fresh retinal tissue obtained from young, adult, and ag ed rats were studied by means of traditional histological methods and by sc anning electron microscopy. Particular attention was paid to morphometrical data and to the changes which occur with ageing. With the aid of a quantit ative analysis of images, a large amount of morphometrical data was collect ed. Moreover, the amount of protein content in retinal tissues has been det ermined. Results: Retinal thickness significantly decreases with age. The ganglion c ells seem to be more vulnerable to age-related loss than other retinal cell s. The number of retinal capillaries is diminished with age. The intercellu lar connections between photoreceptors, the number of cellular processes, a nd the number of synaptic bodies of the bipolar cells also decrease signifi cantly with age. These results were all confirmed by scanning electron micr oscopy observations and morphometrical findings. Biochemical dosage of prot eins demonstrates that retinal tissues decrease with age. Conclusions: All morphological, morphometrical, ultrastructural and biochem ical data are concordant in demonstrating that the retinal tissues of rats undergo specific changes with age. Our findings are in agreement with those described by previous authors and underline that the rat retina can be con sidered an optimal model for studies an neuronal maturation and/or neuronal ageing. Since our data have confirmed that many changes occur in rat retin a with ageing, we can hypothesize that rat retina is particularly sensitive to developmental changes and to senile decay. Jpn J Ophthalmol 2001; 15:68 -75 (C) 2001 Japanese Ophthalmological Society.