A comparative study of total body irradiation as a method of inducing granulocyte depletion in mice

Since conventional methods of inducing depletion of polymorphonuclear granulocytes (PMNs) in mice, such as treatment with cytostatic drugs and anti-PMN sera, proved to be insufficient to induce a stable PMN depletion for several days, and were accompanied by considerable toxic side effects, we induced neutrophil depletion in mice by total body irradiation (TBI) in a single dose of 6.0 Gy (600 rads.) at a dose rate of 0.20 Gy/min. This treatment reduced the number of PMNs in the peripheral circulation to values below 150/microliter from day 3-10 after irradiation. The number of lymphocytes fell simultaneously. Platelet counts remained above 60% of normal values during the first 7 days after irradiation. Complement levels were not significantly affected by TBI. The results show that TBI of 6.0 Gy induces pronounced and stable PMN depletion in mice for at least 7 days. Furthermore, under an aseptic regimen the mice can be kept in good condition and losses are less than 5%.