In Vivo Cytogenetic Effects of 252Cf on Liver and Bone Marrow of the Chinese Hamster

Hamsters were injected with graded activities of 252Cf citrate at pH 6.0 (4.5 × 10−2, 1.5 × 10−2, 5 × 10−3, 1.7 × 10−3 and 5.6 × 10−4 μCi/g body weight), and sacrificed at 6, 15 and 42 days post-injection. The frequency of aberrations in the bone marrow was very low at all times and activity levels. When the animals injected with the three highest levels of 252Cf were considered collectively, the aberration frequency was four times that of the control animals. Many of the aberrations were balanced and had apparently survived cell division. These results suggest that rapidly dividing tissues, such as bone marrow, do not reflect chromosome damage from chronic irradiation to the same degree as slowly dividing tissues, such as liver, because cell division appears to select against damaged cells. The frequency of rings plus dicentrics in the liver, fitted by a power function and a linear regression, increased according to the 1.0 power of the dose with a coefficient of aberration production of 1.7 × 10−3 aberrations/cell/rad. There was a linear increase in the total aberration frequency in liver cells with increasing dose through all the time intervals studied. This increase could be described by the equation Y = 0.05 + 3.3 × 10−3 D where Y = aberrations/cell and D is dose in rads. The coefficient of 3.3 × 10−3 aberrations/cell/rad was approximately half the 7.1 × 10−3 aberrations/cell/rad seen following exposure to 241Am, a pure alpha emitting radionuclide. When only the dose from the alpha emissions of the 252Cf was considered, the aberration coefficient (6.3 × 10−3 aberrations/cell/rad) was not significantly different from that for 241Am.