Morphometric and three-dimensional study of platelets during activation in the rat

Area of Science:

• * Hematology
• * Cell Biology
• * Ultrasonography

Background:

• * Platelet activation is crucial in arterial injury response.
• * Understanding in vivo platelet dynamics aids in developing antithrombotic strategies.
• * Ultrasound-induced arterial damage provides a model for studying platelet behavior.

Purpose of the Study:

• * To investigate the in vivo activation process of platelets following arterial damage.
• * To characterize the morphological changes during platelet activation using electron microscopy.
• * To elucidate the role of platelet pseudopodia in adhesion and locomotion.

Main Methods:

• * In vivo induction of arterial damage in rats using ultrasound.
• * Electron microscopy for high-resolution imaging of platelet ultrastructure.
• * Three-dimensional reconstruction from serial thin sections.
• * Morphometric analysis of platelet compartments and volumes.

Main Results:

• * Platelet activation characterized by granule exocytosis, open canalicular system widening, and pseudopodia emission.
• * Three-dimensional reconstruction revealed pseudopodia adhering to the arterial intima.
• * Evidence of a differentiated locomotor apparatus in adhering platelets.
• * Morphometric analysis showed increased open canalicular system volume and decreased dense granule volume.

Conclusions:

• * In vivo platelet activation involves significant ultrastructural changes, including pseudopodia formation and granule release.
• * Platelet pseudopodia play a role in adhering to the arterial wall, potentially facilitating platelet migration.
• * The study provides detailed insights into the mechanics of platelet adhesion and activation in response to arterial injury.