Keratin staining of canine epithelial tissues by a polyclonal antiserum

The keratin distribution pattern in various canine epithelial tissues has been studied using a commercially available rabbit antiserum, raised against human skin keratins, in an immunoperoxidase staining method with the peroxidase-antiperoxidase complex (PAP). The staining results of two fixation methods were compared. Paraffin sections after fixation in Carnoy's solution showed optimal results, whereas paraffin sections after fixation in 10% buffered formalin resulted in a strongly reduced keratin staining reaction. Keratinizing and non-keratinizing stratified epithelial showed a strong staining reaction. Glandular epithelium and the non-stratified epithelia of internal organs e.g. liver, kidney and intestine did not react with the antiserum. However, glandular ductal epithelium, myoepithelial cells and basal cells in various epithelial tissues showed a positive staining reaction. The results indicate the presence of different keratin types in these canine epithelial tissues. The keratin distribution pattern is compared with the distribution pattern observed in tissues of other species.