Ppw. Vanbuul et al., FURTHER CHARACTERIZATION OF THE RADIOSENSITIVITY OF THE SCID MOUSE, International journal of radiation biology, 74(1), 1998, pp. 35-41
Citations number
38
Categorie Soggetti
Radiology,Nuclear Medicine & Medical Imaging","Biology Miscellaneous","Nuclear Sciences & Tecnology
Purpose: To further characterize the radiation response of the scid mu
tation. Materials and methods: X-ray induced chromosomal aberrations a
nd cell killing were analysed using various in vivo or in vitro cell s
ystems. Results: Using low LET X-irradiation a reverse dose-rate effec
t was found for killing of differentiated and differentiating spermato
gonia and the chromosomal hyperradiosensitivity of scid mice was exten
ded to the meiotic prophase. Most striking was the observation made in
vitro with synchronized established cell lines that, contrary to the
situation in wild-type cells, scid cells display high levels of both c
hromatid- and chromosome type aberrations when irradiated during the G
(1)-phase of the cell cycle. A timecourse for induction of micronuclea
ted polychromatic erythrocytes (MPCE) was determined for scid mice usi
ng flow analysis. No significant differences with wild-type mice were
recorded. The chromosomal radiosensitivity at the G(1) stage in scid c
ells was 4.3 times higher than in control CB-17 cells whereas G(2) sen
sitivity differed only by a factor of 1.3. Conclusions: The reportedly
normal radiosensitivity for MPCE in scid mice together with previous
findings of hypo- or normal radiation sensitivity of scid cells could
be explained by the induction of highly lethal chromatid-type damage a
t the G(1) stage of the cell cycle leading to selective elimination of
aberration-carrying cells. The differences in chromosomal radiosensit
ivity between wild-type and scid for the G(1) and G(2) Stage of the ce
ll cycle correlate with variation in the rates of DNA double-strand br
eak (dsb) repair in scid cells during the cell cycle found by others.