Abstract:
This comparative study was carried out in a lab animal (rabbit)during
the period from June 2007 to September 2007 . The study aimed to
compare between formalin as a routine fixative used in histopathology
laboratories and some formalin substitute fixatives . Three groups of
fixatives are used . This include aldehyde based fixatives ( e.g.
10%formalin ) , alcohol based fixatives ( e.g. Omnifix ) and physical
fixative (e.g. microwave irradiation (MW) ) .
120 biopsies were obtained from rabbit . Of these , 30 biopsies were
fixed by formalin , 30 by omnifix and the remaining 60 were fixed by
microwave for 3min and 5 min . After tissue processing , all sections
were stained with H&E to compare between effect of the fixation on
the feature of nuclear chromatin patterns , cytoplasmic details and the
background staining . Four different histochemical techniques ( silver
impregnation technique , Periodic Acid Schiff's (PAS) , Alcian blue
and Perl's Prussian blue technique) were performed to certain type of
the tissue . In addition immunohistochemistry stain were performed to
show the antigen reactivity on some organs.
Our findings indicated that both formalin substitutes used in this study
(MW and Omnifix ) showed well preservation of the nuclear details ,
cytoplasm appearance and tissue architecture and well
immunoreactivity . On the other hand the microwave fixation reduced
the time .We concluded that both MW and Omnifix were provide
adequate fixation for tissue specimens as the same as formalin .
Therefore , we recommended substitution of formalin in our
laboratories to provide a healthy environment and to avoid formalin
carcinogenicity .
