Long-term Effects of Low-level ²³⁹Pu Contamination on Murine Bone-marrow Stem Cells and Their Progeny

Summary

The effects of long-term internal contamination with 13·3 kBq kg^{−1 239}Pu injected intravenously were studied in 10-week-old ICR (SPF) female mice. Radiosensitivity of spleen colony-forming units (CFU-S) and ¹²⁵IUdR incorporation into proliferating cells of vertebral bone marrow and spleens were determined in plutonium-treated and control animals one year after nuclide injection. The CFU-S in ²³⁹Pu-treated mice were more sensitive to X-rays (D₀ = 0·52 ± 0·01 Gy) than in controls (D₀ = 0·84 ± 0·02 Gy). ¹²⁵IUdR incorporation into bone marrow and spleen cells was reduced after plutonium contamination. At one year following plutonium injection, the occurrence of chromosome aberrations was evaluated in metaphase figures of femoral bone marrow cells. The frequency of aberrations increased early after plutonium treatment, at later intervals it tended to decrease but not below the control level. While the relative numbers of vertebral marrow CFU-S decreased significantly, but only to 86 per cent of normal, cellularity of vertebral bone marrow, peripheral blood counts and survival of ²³⁹Pu-treated mice did not differ from the control data.

• plutonium-239
• haemopoietic CFU-S
• ¹²⁵iododeoxyridine
• chromosome aberrations