Perfusion Staining Methods for Visualization of Intact Microvascular Networks in Whole Mount Skeletal Muscle...

Area of Science:

• Vascular biology
• Microscopy techniques
• Skeletal muscle physiology

Background:

• Visualizing the complete microvascular network in whole mount skeletal muscle preparations is challenging.
• Optimal muscle fiber length is crucial for accurate microvascular analysis.

Purpose of the Study:

• To evaluate different fluorescent labeling methods for whole mount skeletal muscle microvasculature.
• To identify the optimal technique for visualizing the entire microvascular network.

Main Methods:

• Intravascular injection of fluorescently labeled lectins (isolectin GS-IB4, wheat germ agglutinin, lycopersicon esculentum) and FITC-labeled gel in CD-1 mice.
• Excising and pinning various skeletal muscles (soleus, EDL, diaphragm, gluteus maximus, cremaster) at optimal sarcomere length.
• Microscopic examination using fluorescence microscopy.

Main Results:

• Wheat germ agglutinin (WGA) and lycopersicon esculentum (LYCO) effectively labeled the entire vascular network, with WGA providing brighter capillary labeling.
• Isolectin GS-IB4 (ISO) primarily labeled arterioles and early capillaries, not the complete capillary or venular networks.
• FITC-labeled gel showed good microvascular labeling, but inconsistent labeling of smaller vessels was observed.

Conclusions:

• Wheat germ agglutinin (WGA) is the optimal lectin for perfusion labeling and visualizing the intact microvascular network in whole mount skeletal muscle.
• WGA can be used with ISO to effectively distinguish between the arteriolar and venous sides of the microvasculature.