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Active leukocyte crawling in microvessels assessed by digital time-lapse intravital microscopy.
Eduard Ryschich1, Vachtang Kerkadze, Paulius Lizdenis
1Department of Surgery, University of Heidelberg, Heidelberg, Germany.
The Journal of Surgical Research
|April 25, 2006
Summary
Leukocyte movement along blood vessel walls is an active process dependent on adhesion molecules. Extravasation requires an additional inflammatory stimulus, as shown by intravital microscopy.
Area of Science:
- Immunology
- Cell Biology
- Physiology
Background:
- Leukocyte active movement is crucial for immune responses.
- Understanding intravascular leukocyte behavior is key to studying inflammation and extravasation.
Purpose of the Study:
- To investigate the physiology and molecular mechanisms of intravascular leukocyte movement using a hybrid microscopy technique.
- To analyze leukocyte crawling and extravasation dynamics in vivo.
Main Methods:
- Utilized intravital microscopy and digital time-lapse video microscopy in Wistar rats.
- Analyzed leukocyte movement and extravasation after TNF-alpha application and blockade of ICAM-1 and CD18 adhesion molecules.
- Compared intravascular leukocyte locomotion with in vitro migration in collagen gel.
Main Results:
- Identified active intraluminal crawling of leukocytes along the endothelium, with an average velocity of 9.0 µm/min.
- Observed that most crawling leukocytes detached without extravasation under basal conditions.
- Demonstrated that TNF-alpha increased extravasation, while anti-ICAM-1 and anti-CD18 antibodies reduced crawling.
Conclusions:
- Digital time-lapse intravital microscopy is effective for studying leukocyte migration.
- Leukocyte-endothelial interactions are dynamic, involving prolonged crawling and detachment.
- Intravascular crawling reflects leukocyte migratory potential and adhesion molecule dependence; extravasation needs a pro-inflammatory stimulus.