Visualization and Measurement of Lymphatic Function In Vivo

Area of Science:

• Physiology
• Biomedical Imaging
• Lymphatic System Research

Background:

• Growing research interest in the lymphatic system requires robust in vivo methods for assessing lymphatic function in rodent models.
• Current assessment methods may lack the precision needed for detailed lymphatic system studies.

Purpose of the Study:

• To present three novel near-infrared fluorescence imaging-based protocols for in vivo assessment of mouse lymphatic function.
• To provide researchers with reliable tools to visualize and quantify lymphatic clearance, vessel contractility, and valve dynamics.

Main Methods:

• Protocol 1: Assesses skin lymphatic function via intradermal injection of a pegylated tracer and monitoring its clearance using near-infrared fluorescence imaging.
• Protocol 2: Noninvasively images lower limb collecting lymphatic vessel contractility and lymphatic flow routing from the paw to lymph nodes.
• Protocol 3: Invasively images collecting lymphatic vessel contractility and valve function, allowing direct compound application for response measurement.

Main Results:

• The developed protocols enable precise measurement of lymphatic clearance from specific skin regions.
• Noninvasive and invasive imaging successfully visualized lymphatic vessel contractility and lymphatic flow dynamics.
• The assays allow for direct assessment of compound effects on lymphatic vessel contractility and valve function.

Conclusions:

• These three near-infrared fluorescence imaging assays offer versatile and reliable methods for evaluating diverse aspects of lymphatic function in mice.
• The protocols support advancements in understanding lymphatic physiology and pathology.
• The developed assays are valuable tools for drug discovery and preclinical research targeting the lymphatic system.