Single optical section of the human descending colon collected in vivo following the topical application of Acriflavine (0.05% in saline; Sigma Pharmaceuticals). Confocal microscopy enables clear imaging of the different cell types comprising the surface epithelium. The mucous secreting goblet cells appear dark and round and have a larger diameter than the surrounding epithelial cells. The columnar cells appear as a continuous mosaic or sheet of polygonal cells. At the surface, they often appear compressed between the goblet cells.
As the focal plane is moved deeper into the tissue, the underlying vasculature within the lamina propria can be observed. This single optical section was collected in vivo following the intravenous administration of 10 ml fluorescein sodium (10 mg/ml; Pharmalab). The capillaries of the mucosa are contained within the lamina propria and form a honeycomb-like network around the crypts. Black shadows in the lumen of the vessels represent red blood cells not labelled by the fluorescent contrast agent. The superficial microvascular network can be more easily imaged by confocal microscopy than conventional histology. This is due to the fact that the confocal endoscope is placed in to contact with the intact mucosa, ensuring alignment of the en face view parallel to the surface and the patent microvascular plexus.
Images courtesy of Professor Adrian Polglase, Cabrini Monash University Department of Surgery, Melbourne, Australia
