Rapid method for paraffin embedding of precision-cut liver slices

Abstract

Precision-cut liver slices (PCLS) are tissue explants extensively used as an ex vivo model for metabolism andtoxicity studies. When in vitro assays are conducted, it is imperative to perform a histomorphological evaluationas part of the viability analyses throughout the assay time. It is considered that good quality PCLS histologicalsections are difficult to obtain because they are hard to manipulate, and may shrink or fold during processing.Moreover, bibliography is not detailed on the embedding processes used. In this article, we propose an adjustedand rapid method for paraffin embedding of PCLS from crossbreed steers. Each PCLS was covered with a piece ofgauze and placed into a histological cassette. These cassettes were submitted to a series of baths: 80 % ethanol for10 min; 3 baths of 96 % ethanol for 10 min; 3 baths of butanol for 10 min; 1 bath of butanol-paraffin (1:1) for20 min in a 60 ◦C laboratory oven; and 3 baths of paraffin for 20 min in a 60 ◦C laboratory oven. Folded paperboxes were used to produce paraffin blocks. It was possible to obtain complete sections with preserved cellmorphology and no artifacts, and tissue appearance was similar to previous PCLS processed through the routineprotocol, demonstrating the adequacy of the method implemented.