X‐ray irradiation of blood is an effective way to prevent transfusion‐associated
graft‐versus‐host disease. Red blood cells (RBCs) from normal donors suspended
in mannitol‐adenine‐phosphate (MAP) medium were irradiated with X‐ray of 15 and
35 Gy in minimum dose. The change of deformability of the RBCs during storage at
4°C for 4 weeks was examined under shear stress of 13–130 dyn/cm
^2
using a rheoscope,
in relation to the hematological and biochemical properties. (1) The
deformability of RBCs was decreased during the storage, and it was further
decreased by the irradiation. In addition, the number of undeformable RBCs
against a given shear stress increased after the irradiation. (2) The cell
volume gradually decreased, while the intracellular hemoglobin concentration
increased. These changes were accelerated by the irradiation. The echinocytic
transformation during the storage was not accelerated by the irradiation. (3)
The content of aggregated proteins reducible with beta‐mercaptoethanol in RBC
membrane increased during the storage, but was not increased by the irradiation.
Membrane lipid peroxidation was not increased during the storage and by the
irradiation. (4) Leakage of potassium ions from RBCs during the storage was
accelerated by the irradiation. In conclusion, shear‐induced deformation of RBCs
stored in MAP medium was impaired by X‐ray irradiation, mainly due to
dehydration caused by excess leakage of potassium ions from RBCs.
