ULTRASTRUCTURAL AND QUANTITATIVE STUDY OF ATYPICAL AGE-RELATED BODIESIN THE HAMSTER BRAIN

Atypical bodies (ABs), related to aging, are described in the central nervous system of normal aged hamsters. Our study used ultrastructural microscopy and quantitative stereology analysis to study these struct ures in the hypothalamus and brain stem of 3, 6, 12, 18, 24 and 30 mon th-old hamsters. We found that these complex bodies have an oval or a round profile with a core of fibrillar or tubular structures rounded b y a cytoplasmic crown. We frequently observed accumulations of organel les displaying evidence of degeneration. We found that these structure s did not appear until 12 months and their frequency increased with ag e from 12 to 30 months. Their size can range from 3 to 10 mu m, althou gh the median size is 6.5 +/- 0.49 mu m in diameter. There is a signif icant correlation between the quantity of these ABs and the animal's a ge. Their appearance in both hamster and human normal aging can provid e an appropriate animal model to yield more information about the norm al aging process. This knowledge of the normal aging process in hamste rs may also give new insights into which processes in the human brain occur with normal aging and which ones may be exacerbated as in Alzhei mer's disease.