Cytogenetic analysis in Chinese hamster cells chronically exposed to low doses of X-rays.
OBJECTIVE
It is important to develop simple experimental models to assess the induction of DNA damage and study the different factors involved under controlled conditions. This paper describes the cytogenetic analysis carried out in Chinese hamster cells (CHO) sequentially exposed to very low doses of X-rays.


METHODS
CHO cells were cultured for 14 passages. Irradiation treatment was performed once per passage, and three irradiation doses were employed: 2.5, 5.0 and 10.0 mSv.


RESULTS
Sequential irradiation of CHO cells did not increase the yield of chomatid- or chromosome-type aberrations. However, a significant increase of achromatic lesions (gaps) was found after the first or second X-ray dose, with all three irradiation doses employed.


CONCLUSIONS
The variation in the frequency of gaps as well as that in the mitotic index during the 14 cycles of radiation could be an indication of the induction of genomic instability. According to this, continuous rises and falls in the frequency of gaps as well as in the mitotic index reflects the simultaneous induction of endogenous DNA damage, cell death and cell survival.
Güerci
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CIGEBA (Centro de Investigaciones en Genética Básica y Aplicada), Facultad de Cs. Veterinarias Universidad Nacional de La Plata, Calle 60 y 118 s/n, CC 296 B-1900-AVW La Plata, Argentina.
Dulout
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F
Seoane
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A
D000818:Animals; D017209:Apoptosis / Q000528:radiation effects*; D016466:CHO Cells / Q000166:cytology; D002470:Cell Survival / Q000528:radiation effects; D002842:Chromatids / Q000528:radiation effects*; D002869:Chromosome Aberrations; D006224:Cricetinae; D020732:Cytogenetic Analysis; D004249:DNA Damage; D004307:Dose-Response Relationship, Radiation; D008677:Metaphase / Q000528:radiation effects*; D011829:Radiation Dosage; D014965:X-Rays