Increased micronucleus frequency in the progeny of irradiated Chinese hamster cells

Abstract

V79 Chinese hamster cells were irradiated with doses of 1-12 Gy 300 kV X-rays. Their colony-forming ability and the frequency of micronuclei in binucleate cells after treatment with cytochalasin B was determined at various times after irradiation. The frequency of micronuclei determined within the first 24 h after irradiation increased with doses up to 4 Gy and decreased as the dose increased further. Up to 4 Gy there was a close correlation between surviving fraction and the fraction of cells without micronuclei although the surviving fraction was 2-3 times lower than the fraction of cells without micronuclei. Six, 10 or 13 days after irradiation with either 9 or 12 Gy the plating efficiency and the frequency of micronuclei after cytokinesis block with cytochalasin B was determined in the irradiated, but surviving, cells. The delayed plating efficiency of irradiated cells was significantly decreased. The proportion of binucleated cells was in the normal range at 6-13 days after irradiation, indicating that the proliferative activity of irradiated but surviving cells was not depressed at that time. The micronucleus frequency, however, was significantly increased at all times after irradiation. There was little heterogeneity of plating efficiency and micronucleus frequency among 12 clones which had been isolated for irradiated cultures, 3 weeks after 12 Gy.

Antigenotoxic potential of rutin and quercetin in Swiss mice exposed to gamma radiation

“…These findings are in good agreement with the earlier studies. [35,36] It has been observed with MN as well as comet assay that the menace of the radiation-induced genomic instability is reduced in the presence of RUT and QRT. Damage to DNA was attested by increased OTM with increasing doses of radiation.…”

Relationship between clonogenic radiosensitivity, radiation-induced apoptosis and DNA damage/repair in human colon cancer cells

“…Several authors have reported a good quantitative inverse relationship between micronucleus frequency and clonogenic survival (Wandl et al, 1989;Jamali and Trott, 1996;Mariya et al, 1997); however, there are also several reports in which such a correlation was not found (Bush and McMillan, 1993;Slavotinek et al, 1993;Villa et al, 1994). Some authors have reported an inverse correlation between apoptotic frequency and cell survival (Radford and Murphy, 1994;Olive and Durand, 1997;Guo et al, 1999), whereas others found no correlation (Yangihara et al, 1995;McKenna et al, 1996).…”

Cytogenetic Effect of Radiation in Seed of Oak (Quercus robur L.) Trees Growing on Sites Contaminated by Chernobyl Fallout

“…This irradiation-induced genome instability is characterized by a high frequency of chromosomal and gene mutations, an increased number of micronuclei, increased micro-and minisatellite variability, increased malignant transformations, and increased clonal heterogeneity. In these cells high rates of gene amplification and disturbance of cell differentiation were also observed (KRONENBERG, 1994;LOEB, 1994;MORGAN et al, 1996;LITLLE, 1998;JAMALI, ROTT, 1996;MEYN, 1997;TROTT, TEIBE, 1998;LIMOLI et al, 1999).…”