Time-lapse cinemicrography and scanning electron microscopy of platelet formation by megakaryocytes
Abstract:
The surface architecture of megakaryocytes undergoing platelet formation in vitro has been examined by time-lapse cinemicrography and scanning electron microscopy. Fragments of mouse bone marrow were placed in culture medium and incubated at 37 degrees C. After several hours mature megakaryocytes migrated out of the marrow and some underwent shape changes so that they eventually appeared as a relatively small central body, housing the nucleus, from which emerged a number of thin processes which resembled platelet chains. Scanning electron microscopy showed that initially the megakaryocyte surface was ruffled but with development of processes it became smoother. Circumferential folds of small amplitude were found on the surface of developing constrictions which separated putative platelets. It is thought they may be associated with the mechanism of extension, but could have a role in establishing the topography of membrane components. Rupture of the chains and release of platelets was not observed; this permits the number of putative platelets formed by individual megakaryocytes to be determined. The putative platelets exhibited features common to circulating platelets when exposed to a glass surface including the development of pseudopodia and, eventually, flattening on to the surface.
Insights
This study visualizes megakaryocytes forming platelets in vitro. Researchers observed the dynamic surface changes and structures involved in platelet generation from these large cells.
Area of Science:
- Cell Biology
- Hematology
Background:
- Megakaryocytes are large bone marrow cells responsible for platelet production.
- Understanding the intricate process of platelet formation is crucial for hematological research.
Purpose of the Study:
- To investigate the surface architecture and dynamic changes of megakaryocytes during platelet formation in vitro.
- To elucidate the morphological features associated with the generation of proplatelets.
Main Methods:
- Time-lapse cinemicrography was used to observe megakaryocyte behavior over time.
- Scanning electron microscopy provided high-resolution images of megakaryocyte surface topography during platelet formation.
Main Results:
- Mature megakaryocytes migrated from bone marrow fragments and extended thin processes resembling platelet chains.
- The megakaryocyte surface transitioned from ruffled to smoother during process extension, with circumferential folds observed at developing constrictions.
- The number of proplatelets formed per megakaryocyte could be determined as chain rupture was not observed.
Conclusions:
- The observed surface features, including folds, may play a role in proplatelet extension and membrane component organization.
- The in vitro model allowed for detailed observation of megakaryocyte morphology and proplatelet formation without the complication of immediate platelet release.
