THROMBOCYTOPENIA IN POLYCYTHEMIC MICE

  • 1 January 1978
    • journal article
    • research article
    • Vol. 92  (5) , 765-771
Abstract
Significant and sustained thrombocytopenia in mice maintained in a polycythemic state with weekly injections of washed packed RBC [red blood cells] prompted examination of the relationship between observed thrombocytopenia and the polycythemic state. Platelet production was determined by measurement of 75SeM [75Se-selenomethionine] incorporation into platelets. Platelet survival was studied with 51Cr-labeled platelets. Platelet sequestration was assessed by measuring the trapped platelet 51Cr-bound radioactivity in the spleens of these animals. Blood volume was calculated by measuring the dilution of injected 59Fe-tagged RBC. These studies failed to reveal decreased platelet production, a shortening of platelet survival or significant splenic pooling as factors contributing to the observed thrombocytopenia. The blood volumes in the polycythemic group of animals were 8.9% .+-. 0.15 (1 SD) body wt vs. 6.4% .+-. 0.69 in the normals (P < 0.001). Contrary to what has been reported for hypoxia-induced polycthemia, transfusion-induced polycythemia apparently does not cause thrombocytopenia by decreasing platelet production. The observed thrombocytopenia may be mainly due to dilution of the circulating platelet mass by the expanded blood volume.