RESUMO
A computer-assisted automatic image procedure was karyocytopoiesis in culture. This analysis system was based on acetylcholinesterase staining, a specific staining for murine bone marrow megakaryocytes, and an image capturing instrument with a computer program. Two kinds of routine megakaryocyte culture methods were used, the plasma clot and the serum-free agar systems. A comparison between manual counting and the instrument was made. The image analysis software was able to distinguish between megakaryocytes (MK) at different stages of maturation. The results show that this analysis system can simultaneously detect not only the number of megakaryocytes and their colonies in each dish, but also the surface area of individual megakaryocytes. In addition, this analysis system functions automatically 24 hours a day and the results obtained are reproducible. Using this system, we have confirmed previous observations that thrombopoietin (TPO) and heparin stimulate both proliferation and maturation of megakaryocytes. In addition, we found that platelet factor 4 (PF-4) significantly reduced the number of megakaryocytes but not their cell surface area, whereas TGFbeta1 decreased both number and surface area of megakaryocytes, suggesting that PF4 and TGFbeta1 negatively regulate megakaryocytopoiesis by different mechanisms. We noticed that megakaryocytes grown under agar culture conditions regularly had an increased size in comparison with those grown in a plasma clot system, which may be an indication that the plasma clot culture media contains an inhibitor(s) of megakaryocyte maturation. Our data indicate that this image analysis system, in addition to its automatic and reproducible features, is more efficient and allows detection of more parameters than routine manual microscopic detection.