Non-aqueous permanent mounting for immunofluorescence microscopy.

It is generally assumed that an aqueous mounting medium is necessary for the preservation of immunofluorescent-labelled microscopical preparations and polyvinyl alcohol-based solutions (e.g. Mowiol) being the most frequently used mounting media; however, both the quality and intensity of the fluorescence signal in most immunolabelled preparations after aqueous mounting slowly diminish with time, and finally, samples become unsuitable for examination. In the present work, we describe a very simple and rapid non-aqueous mounting procedure for cultured cells and tissue sections, which preserves the fluorescent signal in an excellent way after immunodetection or use of other specific labelling methods. It is based on the current histological protocol in which, after fluorescence labelling, preparations are dehydrated in ethanol, cleared in xylene and mounted in DePeX. Using this non-aqueous mounting medium, the fluorescent signal remains high and stable, allowing a suitable and permanent preservation of labelled and counterstained microscopical preparations.