Endothelial Damage by X-Rays Disclosed by Lymph Fistula Studies.

The degree of capillary permeability was assayed in dogs and rats by studying the appearance of components of the blood in the lymph. Marked capillary permeability was indicated in dogs and rats exposed to approximately LD-50 doses of X-rays by the appearance of large numbers of erythrocytes in the lymph. The data indicate that the reduced red cell counts after irradiation are due to the flooding of the lymph compartments and tissue spaces by erythrocytes. The massive erythrophagocytosis and hemosiderosis in sinuses of lymph nodes of irradiated hosts indicate that many of the erythrocytes leaving the blood capillaries are destroyed. Loss of erythrocytes caused by capillary damage and death of aging erythrocytes with inhibition of erythrogenesis(cf. 2) are the main causes of radiation anemia