Effects of X-ray Radiation on the Rheological Properties of Blood Cells

Blood is often irradiated prior to transfusion in the immunodeficient patient to prevent a potentially fatal complication known as transfusion-associated graft-versus-host disease (TA-GVHD).  Leukocytes in the donor blood sample begin attacking various organs and tissues of the recipient.  Irradiation of the blood sample prevents the proliferation of donor leukocytes in the immunodeficient patient and eliminates the risk of TA-GVHD.  Following radiation exposure, blood components that are targeted directly, such as erythrocytes, platelets and leukocytes, may experience changes in their mechanical properties.  This study evaluates the effects of X-ray radiation on the rheology of platelets and leukocytes because the ability of these blood cells to deform is vital to their flow throughout the microvascular system. 

Micropipette aspiration experiments were conducted on platelets and leukocytes exposed to X-ray radiation doses ranging from 0 (control) to 50 Gy.  Irradiated platelets were subject to increased aspiration pressures and aspiration times.  A significant increase in platelet Young's modulus was observed between control platelets and platelets irradiated at 25 Gy and 50 Gy.  Leukocyte cytoplasmic viscosity increased significantly between control and 25 Gy irradiated leukocytes.  In addition, platelets irradiated at 25 Gy and leukocytes irradiated at 50 Gy showed a significant increase in percent activation compared to control cells.  These results indicate that X-ray radiation exposure causes an increase in platelet and leukocyte rigidity and activation, which could affect microvascular rheology.