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Changes in Megakaryocyte Development Following Thrombocytopenia
Author(s) -
MacPherson G. G.
Publication year - 1974
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1111/j.1365-2141.1974.tb00454.x
Subject(s) - megakaryocyte , platelet , bone marrow , irradiation , andrology , thrombopoiesis , chemistry , biology , immunology , haematopoiesis , medicine , microbiology and biotechnology , stem cell , physics , nuclear physics
S ummary . Rats were made thrombocytopenic by total‐body X‐irradiation and changes in megakaryocyte development studied in shielded tibial bone marrow. The platelet count fell from the fourth day after irradiation to reach a minimum value of 19.5% of the initial count 7 days after irradiation. No changes in megakaryocyte development were observed 5 days after irradiation. Megakaryocyte size was increased at day 7, and the increment maintained until day 12. Megakaryocyte numbers were only significantly increased 12 days after irradiation, but differential counts and electron‐microscope autoradiographs suggested increased influx at day 9. Changes in the labelling index of megakaryocytes suggested that some cells already present were undergoing one or more extra endoreduplications. No evidence was obtained for an accelerated megakaryocyte maturation rate or for a sudden release of platelets from mature megakaryocytes. Morphological changes, signifying increased synthesis of protein and demarcation membranes were apparent only in young cells 7 days after irradiation but were present in mature cells by day 12, demonstrating that the response to thrombocytopenia is confined to immature cells.