Quantitative Analyse der Mikrozirkulation von Wunden mit OPS imaging

Abstract

Introduction: Orthogonal polarization spectral (OPS) imaging, implemented into the CYTOSCAN A/R, is a new, recently introduced technique to produce high contrast images of the microcirculation without the necessity for fluorescent dyes. The aim of the study was to validate OPS imaging against intravital fluorescence microscopy (IFM) for microvascular measurements in normal skin and during wound healing. Material and Methods: Experiments were carried out on the ears of hairless mice (n=8). A circular wound was created according to Bondár and coworkers. The diameter of arterioles and venules, red blood cell velocity in arterioles and venules, as well as the functional capillary density were assessed under normal conditions using OPS imaging and IFM. After subsequent creation of the wound these observations were repeated at the identical microvascular regions (days 4, 7, 10, 15) . Images were videotaped and Caplmage was used for offline computer assisted analysis. Results: Using OPS imaging the micorcirculation of wounded skin on ears of hairless mice could successfully be observed. The regression analyses against standard IFM revealed significant correlation for measurements of all micro circulatory parameters investigated. Further statistical analyses using the method of Bland and Altman showed a very good agreement of the data obtained with both techniques. However, for diameter as well as for FCD measurements OPS imaging yielded lower absolute values as compared to IFM. Conclusions: We were able to validate OPS imaging against IFM for the measurement of microvascular parameters in an animal model of skin wound healing. Such a device should now help to study the role of the microcirculation in physiology and pathophysiology during wound healing in patients without the need for a fluorochrome or other invasive approaches. First clinical investigations are promising.