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Evaluation of Mesenteric Microvascular Hyperpermeability Following Hemorrhagic Shock Using Intravital Microscopy
Taylor R Williams1, Ed W Childs2
1Department of Surgery, Morehouse School of Medicine, Atlanta, GA, USA.
Abstract:
Intravital microscopy is a powerful tool for evaluating vascular hyperpermeability in various vascular beds. Hemorrhagic shock after traumatic injury is known to induce microvascular hyperpermeability, life-threatening edema, and microcirculatory perfusion disturbances. Here we describe the microsurgical and imaging methods to study mesenteric vascular hyperpermeability using intravital microscopy, in a rat model of hemorrhagic shock. In this protocol, hemorrhagic shock is induced by controlled withdrawal of blood to reduce the mean arterial pressure (MAP) to 40 mmHg for 60 min, followed by resuscitation for 60 min. To study the changes in vascular permeability, the rats are given FITC-albumin, a fluorescent tracer, intravenously. The FITC-albumin flux across the vessel wall is measured in mesenteric postcapillary venules by determining intravascular and extravascular fluorescence intensity under intravital microscopy. Intravital microscopic evaluation of high molecular weight FITC-albumin permeability is a reliable indicator of microvascular hyperpermeability.
Insights
Hemorrhagic shock increases vascular permeability, leading to edema. Intravital microscopy effectively measures this microvascular hyperpermeability using FITC-albumin in rats.
Area of Science:
- Physiology
- Microcirculation Research
- Trauma Medicine
Background:
- Hemorrhagic shock following trauma causes microvascular hyperpermeability, edema, and perfusion issues.
- Intravital microscopy is crucial for assessing vascular permeability in different vascular beds.
Purpose of the Study:
- To detail methods for studying mesenteric vascular hyperpermeability using intravital microscopy.
- To establish a rat model of hemorrhagic shock for this research.
Main Methods:
- Inducing hemorrhagic shock by reducing mean arterial pressure to 40 mmHg for 60 minutes, followed by resuscitation.
- Administering FITC-albumin (fluorescent tracer) intravenously to assess vascular permeability.
- Quantifying FITC-albumin flux across mesenteric postcapillary venules via intravital microscopy.
Main Results:
- Intravital microscopy allows for the evaluation of vascular hyperpermeability.
- FITC-albumin flux measurement is a reliable indicator of microvascular changes.
Conclusions:
- This protocol provides a reliable method for assessing microvascular hyperpermeability in hemorrhagic shock.
- Intravital microscopy of FITC-albumin flux is a valuable tool for understanding shock-induced vascular changes.
