title: Identification and distribution of megakaryocyte colonies in murine spleen.
abstract: This study is the first report on the utilization of specific cell function to identify splenic megakaryocytic colonies. Stem cell differentiation into megakaryocytes was studied by injecting each irradiated murine syngeneic recipient with 1 x 10(6) spleen cells. Morphological identification of erythroid, granulocytic, megakaryocytic, and mixed and undifferentiated colonies was done by staining consecutive cryostat sections with hemotoxylin and eosin, benzidine, myeloperoxidase, and acetylcholinesterase. The variation in the distribution of hemopoietic colonies within the spleen was reflected in the different ratio values derived for erythroid, granulocytic, and megakaryocytic colonies at varying depth within the spleen. An increase by 50% of megakaryocyte colonies was seen within the splenic pulp in the midzone region, compared with the surface. This suggests a localized microenvironment conducive for megakaryocytopoiesis. The data emphasizes the importance of identifying colonies of all cell types in histological sections of the spleen and evaluating spleen sections at least at two levels, one adjacent to the surface and the other in the midzone area.
mesh_terms: D000818:Animals; D005260:Female; D008533:Megakaryocytes / Q000637:transplantation*; D051379:Mice; D008810:Mice, Inbred C57BL; D013154:Spleen / Q000166:cytology*