title: Interindividual variation in cytogenetic response to X-ray and colchicine measured with the cytokinesis-block micronucleus assay.
abstract: Interindividual variation in cytogenetic response to two different types of micronucleus (MN) inducer, X-rays (a clastogen) and colchicine (a spindle poison), was investigated in the peripheral blood lymphocytes of normal healthy donors by the cytokinesis-block MN method. The data for 124 donors between the ages of 19 and 80 years showed that the histogram of individual frequency of X-ray (2 Gy)-induced micronucleated cells followed the normal distribution (Shapiro Wilks W-test) with a significant interindividual variance (ANOVA, p < 0.001). This was, however, not the case for colchicine (0.03 microgram/ml)-induced micronucleated cells. Instead, a skewed distribution illustrating interindividual variation was evident (ANOVA, p < 0.001). Statistical analysis of the effect of age and sex on MN incidence by using the Kruskal-Wallis test indicated that age affected the baseline and colchicine-induced MN incidences strongly but not the X-ray-induced MN incidence. There was no effect of sex on the incidence of micronuclei induced by either agent. In order to avoid any possible effect of age on the MN index, data for young subjects aged less than 30 years old were analyzed separately. The results of this analysis again showed significant interindividual variations in baseline, X-ray-induced, and colchicine-induced micronucleated cell rates. Results of the correlation-coefficient analysis showed that neither X-ray-induced MN incidence nor colchicine-induced MN incidence was related to baseline MN incidence. No correlation between X-ray-induced and colchicine-induced MN incidences was also found by this analysis. These results suggest that interindividual variance in chromosomal response to mutagens in normal populations may be a real phenomenon, as is interindividual variance in baseline MN frequency, and that individual susceptibilities to the two different types of micronucleus inducers (X-ray and colchicine) are unrelated, and the baseline MN level is not of predictive value for the susceptibilities.
authors.affiliation: Division of Human and Health Sciences, Yamanashi Prefectural College of Nursing, Japan. byi04452@niftyserve.or.jp
authors.forename: Y
authors.initials: Y
authors.lastname: Odagiri
authors.forename: H
authors.initials: H
authors.lastname: Uchida
authors.forename: S
authors.initials: S
authors.lastname: Shibazaki
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging; D003078:Colchicine / Q000633:toxicity*; D005260:Female; D014644:Genetic Variation; D006801:Humans; D008297:Male; D048629:Micronuclei, Chromosome-Defective / Q000187:drug effects / Q000235:genetics* / Q000528:radiation effects; D015162:Micronucleus Tests / Q000379:methods*; D008875:Middle Aged; D009154:Mutation; D012727:Sex Characteristics; D014965:X-Rays
chemical_list: D003078:Colchicine