The Hamster Cheek Pouch Preparation as a Model for Studies of Macromolecular Permeability of the Microvasculature

A method for intravital microscopy studies of macromolecular permeability is described. The cheek pouch of an anaesthetized hamster was everted and a single layer preparation was mounted on a microscope stage and dissected during observation with a stereomicroscope at 10–16 times magnification. The cheek pouch preparation was superfused with a buffered electrolyte solution with pH=7.35 at 37°C and with a PO2<4kPa (<30 mmHg). Fluorescein labelled dextran ωw,=145000 (FITC-dextran 145) was used as a tracer for permeability.Sites of microvascular permeability to macromolecules were indicated by extravasation of FITC-dextran 145. Leakage of this tracer from the microcirculation was found to occur at the postcapillary venules only. The number of FITC-dextran leakage sites was used for quantitation of the permeability during intravital observations in untreated control and indomethacin-treated hamsters. The number of leakage sites was significantly increased at 120 min in control hamsters but not until 300 min i...