Genetic Labeling of Cells Allows Identification and Tracking of Transgenic Platelets in Mice.

Background: The use of knock-out mouse models is crucial to understand platelet activation and aggregation.

Methods: Analysis of the global double fluorescent Cre reporter mouse that has been crossbred with the megakaryocyte/platelet specific mouse.

Results: Platelets show bright ( negative) and ( positive) fluorescence. However, a small proportion of leukocytes was positive for fluorescence in positive mice. In mice, platelets, and megakaryocytes can be tracked by their specific fluorescence in blood smear, hematopoietic organs and upon thrombus formation. No differences in platelet activation and thrombus formation was observed between positive and negative mice. Furthermore, hemostasis and in vivo thrombus formation was comparable between genotypes as analyzed by intravital microscopy. Transplantation studies revealed that bone marrow of mice can be transferred to mice.

Conclusions: The reporter mouse is an appropriate model for real-time visualization of platelets, the analysis of cell morphology and the identification of non-recombined platelets. Thus, mice are important for the analysis of platelet-specific knockout mice. However, a small proportion of leukocytes exhibit fluorescence. Therefore, the analysis of platelets beyond hemostasis and thrombosis should be critically evaluated when recombination of immune cells is increased.