Figure 1. Intra-vital imaging maintains intact blood flow without damaging the pancreas.

A) Setup for intra-vital 2-photon pancreas imaging. A heated suction window stabilizes the surgically exposed pancreas for imaging. B–C) Representative maximum intensity projection images of islets imaged intra-vitally through the suction imaging window captured using 2-photon microscopy. Vascular space is labeled with 70kD dextran-rhodamine (red). Images are representative of 7 experiments. B) Islets are identifiable by their dense convoluted vasculature compared to exocrine tissue vasculature. The border of the islet is identified with a yellow dotted line. Scale bar = 30μm. C) NOD mouse islet with transferred BDC-2.5 T cells (green). The collagen fluorescence is provided by the second harmonic (blue) which demonstrates that the T cell infiltration is inside the islet basement membrane. Scale bar=100μm. D) Neutrophils do not accumulate at the site of imaging. Fluorescently labeled neutrophils were transferred into mice prior to surgical exposure and imaging of the pancreas through the suction window. The number of neutrophils was counted every ninety seconds. The lack of neutrophil accumulation shows that the imaging site was not damaged during imaging. Data are representative of 1 islet per mouse in 3 experiments. E) Suction imaging window does not impede blood flow. Fluorescent beads were tracked within blood vessels of different diameter within and around the pancreatic islets. Each dot represents one bead. Data are representative of 3 islet per mouse in 2 experiments.