The use of sodium chloride-containing fixatives in minimizing cellular distortion in histological and cytochemical preparations.

Abstract

The principal objective of this study was to determine the relative effect of the concentration of small, mobile ions in fixing solutions on cellular shrinkage and distortion occurring during fixation or in the subsequent processing of tissues by the paraffin method. Samples of rat liver tissue were fixed in neutral 20% formalin, neutral 20% formalin/0.7% sodium chloride, Bouin's fluid, and Bouin's fluid/0.7% sodium chloride. By a comparison of nuclear and cytoplasmic volumes, it was noted that in the case of formalin fixation, the addition of 0.7% sodium chloride reduced nuclear and cytoplasmic shrinkage by 18-26%. In Bouin fixation the addition of 0.7% sodium chloride reduced nuclear shrinkage by 7-10% and cytoplasmic shrinkage by approximately 21%. It was also shown that when the sodium chloride is omitted, neutral 20% formalin is significantly less effective than Boumin's fluid in stabilizing the cytoplasm of liver parenchymal cells against shrinkage. In those instances in which tissue shrinkage was minimized by the addition of sodium chloride to the fixing medium, the final preparations revealed less tissue distortion and a more adequate preservation of fine detail. Some mention is also made of differences incurred in staining reactions of liver tissue following the use of sodium chloride containing fixatives.