Kinetic Repair of Chromosome Breaks of Normal Human Liver Cells Induced by Low LET Rays

Key words: 
• kinetic repair /
• chromosome break /
• human liver cell

Abstract: We employed the prematurely chromosome condensation （PCC） technique to investigate the 48 h kinetic repair of normal human liver cell line L02 exposed to γ-rays. The results showed that chromatidtype and isochromatid-type breaks increased with the dose at 0 h measured by PCC, the number of chromatid-type breaks was several times more than that of isochromatid-type breaks. Further 24 h incubationafter exposed to irradiation, both of these two type breaks decreased in different extent, 50% for chromatid-type one, change of the the main type easy to repair. 15% for isochromatid-type one at most, respectively. chromosome breaks compared with that of 24th h（p〉 0. 05 of the chromosome breaks was chromatid-type after exposed 48th h, there was a slightly ）. These results revealed that to low LET rays, also, it was Though the isochromatid-type breaks was obvioously less than that of the chromatid-type one, it was difficult to repair. It implied that the isochromatid-type breaks was the important factor causing cell death and canceration when cells were exposed to irradiations.