THE RADIOPROTECTIVE EFFICACY OF THE RAT ACUTE-PHASE PROTEIN ALPHA2-MACROGLOBULIN ON BONE MARROW CELLS

Mihajlovic M., M. Vidakovic, N. Grdovic, S. Dinic, A. Uskokovic, V. Martinovic and J.Blagojevic (2009): The radioprotective efficacy of the rat acute-phase potein alpha2-macroglobulin on bone marrow cells-Genetika, Vol. 41, No. 1, 29-39. The rat acute phase protein alpha(2)-macroglobulin (alpha 2M) plays an important role in the restoration of disrupted homeostasis by inhibiting different types of non-specific proteases and facilitating the transport of cytokines, growth factors and hormones. Previously, we observed that administration of alpha 2M to experimental animals prior to the infliction of life-threatening trauma in the form of scalding or total-body irradiation, significantly improved their survival rates. The aim of the present work was to evalute the radioprotective effect on blood cells of alpha 2M that, when administered 30 min before irradiation with 6.7 Gy (LD50/30), provides 100% survival of experimental animals where in unprotected irradiated rats the said dose results in 50% lethality. We observed that rats pretreated with alpha 2M, after an initial decline, exhibited complete recovery of the leukocyte count due to the preservation of bone marrow cells, observed as a stable mitotic index. In untreated irradiated rats the decrease of the mitotic index reflected the significant destruction of bone marrow cells that resulted in a protracted decline in the leukocyte count. We conclude that the radioprotection provided by alpha 2M was in part mediated through cytoprotection of new blood cells produced in the bone marrow.