Comparison study of different fixative solutions

Abstract

Fixation is a method with the aim of preserving the structural and functional components in the tissue and cells as closely as possible in a state similar to that of a living state. For decades 4% formaldehyde has been the dominating chemical solution when fixation is required, making it the golden standard for fixation around the world. Unfortunately 4% formaldehyde is toxic, causing regular skin irritations and is considered to be carcinogenic.
The purpose of this study was to find a less toxic fixation solution that could yield the same adequate results of preserving the cell morphology as 4% formaldehyde. For that purpose HistoChoice and bladder irrigation fixatives were chosen to be tested as alternative fixatives and the results were compared to 4% formaldehyde fixated paraffin embedded tissues.
This study was conducted at Kristianstad University and began with collecting animal organs (liver, lung and heart) of a pig. Twelve tissue samples were cut of every organ and fixated in all 3 fixation solutions respectively. The tissues were fixated according to 4 different fixation time frames, 18h, 24h, 72h and 144h. When fixation was done, the tissues were dehydrated, paraffin embedded, sectioned using a microtome and stained with hematoxylin & eosin (H&E) staining protocol. Evaluation of the results was conducted according to the quality of the obtained sections, the ability to distinguish the nuclei of the cells from the cytoplasm, the ability to distinguish chromatin fibers within the nuclei of the cells and the ability to separate different parts of the cytoplasm by color shifting.
The results obtained from tissues fixated with 4% formaldehyde and HistoChoice yielded excellent quality in the chosen criteria. Tissues fixated in bladder irrigation fixative did not yield adequate results compared to 4% formaldehyde.
We therefore conclude that HistoChoice is a possible fixation alternative and could in some aspects replace 4% formaldehyde.

Date of Award	2013-Dec
Original language	English
Supervisor	Helena Tassidis (Supervisor) & Annette Persson (Examiner)