Free-floating cryostat sections for immunoelectron microscopy: Bridging the gap from light to electron microscopy

Frozen skin sections are routinely used for light microscopic immunohistoch emical study of the skin basement membrane zone for two reasons: some skin basement membrane zone proteins are labile to routine chemical fixation, an d skin is not amenable to vibratome sectioning. However, inherent limitatio ns of conventional frozen sections, including compromised morphology and a requirement for glass slide-mounting, usually limit immunohistochemical stu dy to the light microscopy level. In the present study, we introduce use of unfixed, free-floating cryostat sections for characterization of immunoloc alizations of selected skin basement membrane proteins at both the light an d electron microscopy level. The new procedure employs free-floating cryost at sections that can be processed as routine tissue specimens and can be su bjected to a variety of special staining procedures including immunohistoch emistry. Especially useful is the ease of progressive processing of the sam e tissue specimen from light microscopy to electron microscopy. In this reg ard, the method renders itself useful when results of immunolabeling experi ments need to be elucidated quickly at histological and ultrastructural lev els as required for diagnostic and accelerated investigative strategies. (C ) 2001 Wiley-Liss, Inc.(dagger).