6th ESACP Congress, Heidelberg, April 7-11, 1999

A135
CHANGES IN HEMOPOIESIS DURING THE AGEING OF ANIMALS.
Tokalov AS, Yagunov AS

Central Research Institute of Roentgenology and Radiology, St.Petersburg, Russia

Aim: Revealing the specific age changes in cells and tissues is one of the main problems of gerontology. Under real environmental conditions, humans and animals are constantly exposed to background amounts of electromagnetic (e.g. ionizing) irradiation as well as to chemical toxicants from the environment, including such heavy metals as lead (Pb), cadmium (Cd), etc. The aim of study was to trace age-associated blood and bone marrow changes of intact animals and its modifications after the action of chronic irradiation or/and heavy metalls. Methods: Longitudinal observations of 3250 locally bred male Wistar rats were performed. Chronically irradiated animals have received total radiation doses between 0.12-4.0 Gy (0.28-10.0 mkGy/sec) and cadmium chloride (5 mg/l) or lead acetate (50 mg/l). Flow cytometric DNA cell cycle analysis, bone marrow reconstitution of lethally irradiated rats blood as well as peripheral blood and bone marrow differentials were used to trace the functionality of the hemopoietic system. Results & Conclusions: The process of normal ageing in rats was accompanied by generally decreased blood cell production, along with limited rates of stem cell proliferation. The percentage of bone marrow cells in S+G2+M phases is increased with age of rats, that is accompanied by reduction of amplitude of annual fluctuations of specified parameters. Chronic irradiation resulted in a stable increase of myelokaryocyte share in S-phase. This effect proved to predominate at longer terms elapsing after combined radiation/metal treatment.