Current Technologies for Fixation of Biological Material for Immunohistochemical Analysis (Review)

Abstract

Based on their own experience and published reports the authors provide an insight into the existing methods of fixation of biological material used in immunohistochemistry. The first quality of an immunohistochemical fixative should be its ability to preserve the tissue structure so that the antigenic properties of macromolecules are minimally affected. Considering this point, the review analyzes the applicability of commonly used fixatives to immunohistochemical staining; among those, aldehydes (formaldehyde, glutaraldehyde, glyoxal), dehydrating (coagulating) agents (ethanol, methanol, acetone), combined fixation solutions (Bouin's solution, Carnoy's solution, methacarn, etc.), as well as the recent zinc-containing fixatives and commercial products. Most of these fixatives inevitably change the tertiary and quaternary structure of many proteins; therefore, the detection of these proteins by immunohistochemistry requires an additional procedure of unmasking the epitopes using proteolytic enzymes or elevated temperatures. When compared for the preservation of antigenic structures, a high quality of the novel zinc-containing fixative -zinc-ethanol-formaldehyde -was noted. It has been concluded that none of the fixatives known to date has such a combination of properties that allow obtaining high-quality histological preparations and, at the same time, allows for detecting of any antigens in the stained tissue.