Proliferation, migration and platelet release by megakaryocytes in long-term bone marrow culture in collagen gel.
The proliferation of megakaryocytes, their migration, and their platelet release processes were observed in long-term bone marrow culture in collagen gel. Megakaryocytes proliferated for more than 6 months, not only with myeloid cells but also with sinusoid-like capillaries. The megakaryocyte count decreased at 2 weeks of culture, increased to more than 400 at 6 weeks, and then decreased to about 100. Megakaryocyte colonies appeared after 2 weeks of culture; the number increased to more than 10 at 4 weeks of culture, and was maintained at that level. Morphologically, most fully mature megakaryocytes extended several long antennae-like processes, with periodic constrictions, demarcation membranes (DM), and platelet fields. Pro-platelets were released from these processes primarily by a "pinching off" mechanism, but some megakaryocytes released pro-platelets by the dissociation of DM, without extending long processes. Mature megakaryocytes migrated like ameba in collagen gel, and a few migrated to the abluminal side of the capillary or into the capillary; in both cases releasing pro-platelets into the capillary lumina. These observations were very similar to those noted in vivo.
Faculty of Health and Welfare Science, Okayama Prefectural University, Japan.
M
M
Mori
J
J
Tsuchiyama
S
S
Okada
D000818:Animals; D001792:Blood Platelets / Q000166:cytology*; D001854:Bone Marrow Cells; D002450:Cell Communication / Q000502:physiology; D002452:Cell Count; D002455:Cell Division / Q000502:physiology; D002465:Cell Movement / Q000502:physiology; D003094:Collagen; D046508:Culture Techniques; D005782:Gels; D008533:Megakaryocytes / Q000166:cytology* / Q000648:ultrastructure; D051379:Mice; D008809:Mice, Inbred C3H; D017154:Stromal Cells / Q000166:cytology; D013997:Time Factors
D005782:Gels; D003094:Collagen