EFFECTS OF IONIZING AND NONIONIZING RADIATION ON RAT HEMATOPOIESIS

Alterations of the marrow cellularity in male Wistar rats under the co mbined action of millimeter waves (MMW) and gamma rays were studied. M MW with wavelength of 5.6 mm (frequency 53.53 GHz) or 7.1 mm (42.19 GH z) were applied to the right hindleg shank of the animal for 20 min da ily for 10 days using a Yav'-1 generator (Russia). Two of the test gro ups were also irradiated with gamma rays (6 Gy) immediately following the last treatment with MMW. Nucleus-containing cells in the marrow fr om a 1-cm-long piece of thigh bone were counted on days 3, 7, 14, 21, and 30 after the last treatment with MMW or after the gamma irradiatio n. The treatment of the animals with 5.6 mm electromagnetic waves (EMW ) only showed an increase of marrow cellularity compared to the contro l group after day 14 until the end of the investigation period. An inc rease in marrow cellularity after exposure to 7.1 mm EMW was observed at the seventh day following exposure. Exposure of the rats to MMW pri or to gamma irradiation reduced the radiation damage of hemopoiesis in the early postirradiation period. The exposure to MMW increased the q uantity of marrow karyocytes after the ionizing exposure and preserved the proliferating capability of the stem cells and their active diffe rentiation. The results of this study showed that bone marrow cellular ity returned to control values on day 7 after gamma irradiation, and g reater effect was achieved using 7.1 mm EMW.