Imaging of Skin Epidermis from Various Origins Using Confocal Laser Scanning Microscopy

The ability to image the subsurface morphology of intact three-dimensional matrices such as skin epidermal tissue, using conventional optical microscopy, requires the tissue to undergo an extensive preparative protocol. This protocol includes fixing, embedding and physically sectioning the specimen. The process is slow and subject to sample perturbation, which can result in image misinterpretation. In this study, confocal laser scanning microscopy is used successfully for the imaging of the surface and underlying morphology of unlabelled and fluorescently labelled intact skin epidermal tissue, from various origins (that is human, pig and cultured epidermis). Unlike conventional optical microscopy, the technique requires little or no pretreatment of the tissue prior to imaging. Hence the technique is rapid, and the tissue experiences minimal physical perturbation and/or damage. Confocal images of skin epidermis in the reflected light (unlabelled) and fluorescent modes were obtained. In the reflected-light mode the detailed morphology of the various layers of the intact epidermis (that is the strata corneum, granulosum, spinosum and basale) from a variety of sources are clearly imaged. In the fluorescent mode, environment-specific information is obtained. For example, topical application of the fluorescent probe acridine orange readily allows the confocal imaging of the nuclear material (nuclei and nucleoli), from cells of the different strata of intact epidermis. In the case of the fluorophore Nile red, however, visualisation of the lipid material of the epidermis, including the intercellular lipid of the stratum corneum and the lipid granules of the stratum granulosum, is possible. he reflectance and fluorescence confocal images are sel-consistent and agree with images obtained by conventional, physical sectioning protocols.(ABSTRACT TRUNCATED AT 250 WORDS)