In vivo assessment of colon microcirculation: comparison of the new OPS imaging technique with intravital microscopy

The Orthogonal Polarization Spectral (OPS) imaging technique has been introduced for in vivo assessment of microcirculation in humans. Unclear remains, whether the new technique would allow for accurate investigations of the colon microcirculation with respect to the unique conditions of the microvasculature in that particular tissue. Therefore, the aim of this study was to validate the new technique against intravital fluorescence microscopy (IFM) for the visualization of colon microcirculation in a murine model of inflammatory bowel disease (IBD).

IBD was induced in Balb/c mice by dextran sulfate sodium (DSS), controls received normal water. In each animal, both the CYTO-SCAN A/R and IFM were used to image the microcirculation (n = 7 in each group). Postcapillary venular diameter, venular red blood cell velocity (RBC-V) and functional capillary density (FCD) were analyzed on the colon muscularis and mucosa and compared to each other using linear regression analysis and Bland-Altman plots.

All parameters correlated significantly between the both methods. The venular diameters and the RBC-V were significantly different between control and colitis group in contrast to FCD; these results were present while using both methods.

Our study demonstrates that the new technique for visualization of microcirculation without use of fluorescent dyes, the OPS-imaging, allows for quantitative measurement of the key microcirculatory parameters of the mouse colon.