Lack of correlation between apoptosis and DNA single-strand breaks in X-irradiated human peripheral blood mononuclear cells in the course of ageing.
The dependence on age of both the basal and the X-radiation-induced levels of apoptosis was examined in human peripheral blood mononuclear cells (PBMC). In the same samples, the base value and the extent of induced DNA single-strand breaks were determined, using a sensitive and fast microplate assay. PBMC were isolated from blood of donors of various age groups (20-30, 40-60 and > 70 years of age) and X-irradiated ex vivo using a 6 MV linear accelerator to give a total exposure of 4 Gy. The mean basal levels of apoptosis in PBMC from donors in the 40-60 year age group and the > 70 year age group were found to be only slightly higher (by 20-10%) compared to that of the 20-30 year age group, whereas the extent of DNA damage strongly and significantly (P < 0.01) increased with age by up to 2-fold. In contrast to the extent of induced DNA damage, which steadily increased in the course of ageing by up to 1.8-fold, there was only a transient increase in the level of induced apoptosis to 1.5-fold in PBMC from X-irradiated blood (4 Gy photons) from donors aged 40-60 followed by a decrease to 0.9-fold in PBMC from old donors (>70), compared to age group 20-30. The results show that X-ray-induced apoptosis and DNA damage in PBMC are not correlated during ageing.
Chauvin
C
C
Institut für Physiologische Chemie, Abteilung Angewandte Molekularbiologie, Universität, Mainz, Germany.
Heidenreich
E
E
Elmendorff-Dreikorn
K
K
Slor
H
H
Kutzner
J
J
Batel
R
R
Schröder
H C
HC
D000375:Aging / Q000528:radiation effects*; D017209:Apoptosis / Q000528:radiation effects*; D004277:DNA, Single-Stranded / Q000528:radiation effects*; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000528:radiation effects; D014965:X-Rays
D004277:DNA, Single-Stranded