Immunohistochemical examinations of canine myocardium. 2. Cell adhesion markers

The aim of the present study was to analyse the imunreactivity of twelve cell junction markers including claudin-1, -2, -3, -4, -5, -6, -7, -8, -10, -18, occludin, and beta-catenin in canine cardiac muscle cells in routinely processed formalin-fixed paraffin embedded tissues. In the course of their work, the authors separated the heart from 10 adult dogs which died due to non-cardiac origin. The following anatomical samples were taken from the heart: right atrium, right ventricle free wall, left atrium, left ventricle free wall, and interventricular septum. All samples were transmural necropsy sample, which contained the epicardial and endocardial surfaces, as well. During the immunohistochemical analysis the subepicardial, the intermediate and the subendocardial cardiomyocytes were negative for all cell junction proteins. Perineural epitheloid cells of the subepicardial and intramyocardial nerves showed intense claudin-1 membrane positivity. Endothelial cells of vasculature of the heart showed intense claudin-5 immunreactivity. In the myocardium the discus intercalaris was positive for beta-catenin.