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6th ESACP Congress, Heidelberg, April 7-11, 1999 |
A135
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.
CHANGES IN HEMOPOIESIS DURING THE AGEING OF ANIMALS.
Tokalov AS, Yagunov AS
Central Research Institute of Roentgenology and Radiology,
St.Petersburg, Russia