Radiation-induced chromosome aberrations and dominant lethality of germ cells and their biological significance

The chromosome aberration rates and dominant lethality of germ cells in male mice at different interval times after acute and chronic radiations were investigated. The acute irradiation was carried out with X-rays at dose rates and doses of 0.05 Gy/min, 0-1.0 Gy and 0.44 Gy/min 2.0 Gy, respectively. The chronic irradiation was performed with 60Co γ-rays at dose rate and cumulated dose of 4.17 x 10-5 Gy/min and 0-2.1 Gy, respectively. The results indicated that the dominant lethality was induced through chromosome aberrations of germ cells. The time of fertilization after irradiation influenced prominently on the chromosome aberration rates and dominant lethality. In the acute exposure group, fertilization time was 140 days, after irradiation with 2.0 Gy, and the spermatogonia were mainly injured. The dominant lethality was 9.23% for the irradiated and 5.73% for the blank controls (P>0.05). In the chronic exposure group, the fertilization time was 24 days after irradiation with 2.1 Gy, and the primary spermatocytes were mainly injured; the dominant lethality was 16.36% for the irradiated and 5.83% for the blank controls (P<0.05). These findings suggest that persons receiving acute radiation exposure from nuclear explosion or radiation accident may develop genetic harm while those subjected to occupational chronic radiation exposure may not