Alterations of Hematopoiesis Markers Induced by Exposure to Cobalt-60 or Cesium-137 in albino mice

Abstract

Ionizing radiation from radioactive isotopes such as Cobalt -60(Co-60) and Cesium-137(Cs-137) is widely employed in medical, industrial, and scientific applications; uncontrolled exposure poses a serious hazard to biological systems. This study aimed to evaluate and compare the time -dependent toxicological effects of Co-60 and Cs-137 gamma radiation on hematopoietic dynamics and cell morphology in male albino mice. Forty- two adult male albino mice were divided randomly into seven equal groups (n = 6): one unirradiated control and six irradiated groups exposed to either Co-60 or Cs-137 for 6,12,24 hours. Hematological parameters, including red blood cell count, Hemoglobin concentration, platelet count, white blood cell counts, and leukocyte differential count, were analyzed alongside cytomorphological evaluations of peripheral blood and bone marrow smears. Platelets have the greatest radio sensitivity, exhibiting severe thrombocytopenia at all intervals, while leukocytes declined rapidly and erythrocytes showed delayed depletion. Blood and bone marrow smears revealed progressive morphological damage over time, transitioning from initial chromatin clumping to widespread stromal aplasia, ghost membrane formation, nuclear pyknosis, and karyorrhexis by 24 hours. High-energy Co-60 induced an earlier onset of cellular toxicity, whereas Cs-137 displayed a brief latent period before converging to equivalent systemic damage. Both Co-60 and Cs-137 induce severe, duration-dependent hematopoietic failure and bone marrow aplasia in male albino mice. While higher-energy Co-60 accelerates the initial onset of myelosuppression, both isotopes result in equivalent late-stage cytopathological destruction, highlighting the critical necessity for rapid therapeutic intervention following acute gamma radiation exposure.