[Effect of paraformaldehyde fixation on the qualitative preservation and stereological parameters of the adult rat liver].

Abstract

Studies were made to compare the impact of immersion fixations with different concentrations of paraformaldehyde (10%, 6% + 0,25% glutaraldehyde, 4% and 1%) on the cellular and subcellular structure preservation. The study was performed on 3 animals. Similar conditions existed for all the preparative steps, since they were done in one operation. Cellular parameters as the volume densities of hepatocytes (VVH), nuclei (VVNH), cytoplasm (VVCYT) and extra-hepatocytic space (VVEX) were assessed by light microscopy on toluidine blue stained semi-thin sections at X 1 000. The volume (VVM), the surface density of mitochondria (SVMO) and their mean profile size (am) were measured at the electron microscopic level (X 15 000). The most striking differences were observed in the volume density (VVM), surface to volume ratio (SV) and mean profile area of the mitochondria (am). Qualitative results revealed that the zone of good electron microscopic observation varied according to the concentrations of the fixative. In conclusion, the best qualitative and quantitative preservation is assumed with 4% paraformaldehyde and at a less degree with 6% paraformaldehyde + 0,25% glutaraldehyde.