Why does longitudinal imaging matter for target validation in metabolic disease?

Longitudinal imaging enables repeated observation of cellular dynamics in the same animal over time, allowing researchers to assess the durability and consistency of target-mediated effects on beta cell function and islet architecture, which supports more confident go/no-go decisions in target validation programs.

How does isolating pancreatic islets from bowel motion improve data quality?

The metal plate-supported imaging window spatially separates the pancreas from the bowel, reducing motion artifacts from peristalsis and enabling stable, high-resolution imaging of cellular structures, which is essential for reliable quantitative measurements in assay development.

What quantitative measurements enable assessment of beta cell function in this model?

The method allows measurement of beta cell migration, intracellular calcium flux, islet size, and vascular perfusion through time-lapse and z-stack imaging, providing functional readouts that link genetic or pharmacological interventions to phenotypic outcomes in a disease-relevant system.

Why are replication requirements important for cross-functional collaboration in imaging-based assays?

Replication ensures that imaging results are consistent across animals, operators, and experimental runs, which is critical for building confidence in assay outputs and enabling reliable comparison of compound effects between discovery, translational, and preclinical teams.

What statistical analysis capabilities are required before implementing intravital imaging in a discovery pipeline?

Implementation requires capability for quantitative image analysis, including fluorescence intensity tracking, object segmentation, and time-series statistics, to compare conditions and assess significance of observed changes in cellular dynamics or structure.

Intravital Imaging: A Method for Cellular Level Observation of the Mouse Pancreas Through a Stabilized Imaging Window

JoVE Encyclopedia of Experiments

Biology

0 views • 3:40 min • July 8th, 2025

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Intravital imaging involves visualizing cells of a live animal through an imaging window implanted into the animal. It enables long-term observation of cellular dynamics without compromising their functions.

To begin, take an anesthetized transgenic mouse previously implanted with a pancreatic imaging window supported on a metal plate. The base plate spatially separates the pancreas from the bowel, thereby reducing motion artifacts from physiological movements such as peristalsis.

The transgenic mouse expresses green fluorescent protein or GFP under insulin gene promoter expressed in beta cells of islets in the pancreas.

Next, hold the mouse tail firmly and spray disinfectant to remove any surface contaminants. Insert a catheter into the lateral tail vein. Inject a solution containing antibodies tagged with a red fluorescent probe into the tail vein. These antibodies bind to the cells lining the blood vessels, staining them red.

Now, shift the mouse to an intravital microscopy setup. Insert the pancreatic imaging window into the window holder. Start imaging under low magnification to locate green fluorescing islet clusters surrounded by red fluorescing blood vessels. Increase the magnification to obtain high-quality cellular level imaging of individual beta cells.

Begin by switching on the intravital microscope, including the laser power. To insert a vascular catheter, apply pressure on the proximal side of the tail with the index and third finger. If necessary, heat the tail with a lamp. Disinfect the tail vein with a 70% ethanol spray, then, insert a 30 gauge catheter into the lateral tail vein and visualize the regurgitation of blood in the PE-10 tube. Apply silk tape on the catheter to stabilize it.

Inject FITC dextran and TMR dextran, or other fluorescent probes, as appropriate, according to the combination of fluorescent probes. Insert a rectal probe to automatically control the body temperature with the homeothermic heating pad system. Then, insert the pancreatic imaging window prepared during intravital microscopy setup into the window holder. Transfer the mouse from the surgical platform to the imaging stage.

To perform intravital imaging, start with imaging the pancreas at a low magnification, such as four times, to scan the whole view of the pancreas in the pancreatic imaging window. Once the region of interest has been determined, switch to a higher magnification objective lens, like 20 times or 40 times, to perform cellular level imaging with lateral and axial resolution approximately 0.5 micrometers and 3 micrometers, respectively.

Perform z-stack or time-lapse imaging to observe the 3D structure or cellular level dynamics, such as cell migration.