In Vitro Studies on the Sensitivity of Canine Granulopoietic Progenitor Cells (GM-CFC) to Ionizing Radiation: Differences between Steady State GM-CFC from Blood and Bone Marrow

Summary

The radiosensitivity of the granulopoietic progenitor cells (GM-CFC) from blood and bone marrow of dogs under steady state conditions was studied by in vitro irradiation with 280 kV X-rays (∼ 0·56 Gy/min). The dose-effect relationship for colony formation was determined for the dose range from 0 to 3 Gy by means of three different models. A simple exponential function revealed an optimal approximation to the experimental data obtained for the clonogenic cells from the two different sources. The D₀ values are 0·261 ∓ 0·009 Gy and 0·600 ∓ 0·011 Gy for the GM-CFC from blood and bone marrow, respectively. Irradiation of blood-derived GM-CFC in the presence of pre-irradiated bone marrow cells or irradiation of bone marrow cells as a mixture with pre-irradiated blood cells led to small changes only in the survival curves. According to the dose–effect relationship obtained from these studies the GM-CFC of the dog seem to be the most radiosensitive clonogenic haemopoietic cells among the different mammals.