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Chromosome aberrations induced by tritiated water or 60Co γ-rays at early pronuclear stage in mouse eggs

1986; Elsevier BV; Volume: 160; Issue: 2 Linguagem: Inglês

10.1016/0027-5107(86)90032-1

1873-135X

Yoichi Matsuda, Takeshi Yamada, Izuo Tobari,

Carcinogens and Genotoxicity Assessment

The induction of chromosome aberrations in mouse eggs by exposure to HTO β-particles and 60Co γ-rays at the early pronuclear stage was examined at the first-cleavage metaphase by using an in vitro fertilization technique. Eggs at the pronuclear stage were exposed to β-particles in a chemically defined medium containing tritiated water (HTO) for 2 h at 3–5 h after insemination. Other eggs at the same stage were exposed to γ-rays from 60Co during the same period. The dose-response relationships for frequencies of chromosome aberrations per egg were fitted to a linear-quadratic model for HTO β-particles, and to a linear model for 60Co γ-rays. The chromosome aberrations were mainly chromosome-type, and the majority of all aberrations were fragments. RBE values of HTO β-particles relative to 60Co γ-rays and acute X-rays, which were estimated from the ratio of the linear regression coefficients over 0.05-Gy range, were 2.0 and 1.6, respectively.