IMMUNOHISTOCHEMICAL DISTRIBUTION OF S-100 PROTEIN AND CYTOSKELETAL PROTEINS (Α-ACTIN, DESMIN AND VIMENTIN) IN BOVINE TONGUE AND SOFT PALATE

Distribution and localization of S-100 protein and cytoskeletal proteins, α-actin, desmin and vimentin, in the bovine tongue and soft palate were investigated using immunohistochemistry. S-100 protein was expressed in the taste buds and connective tissue core of circumvallate papillae, moderate immunoreactivity were occur in subepithelial connective tissue cells of the tongue and soft palate. The serous secreting cells and ducts cells in the lingual salivary gland, as well as serous demilunes of mixed palatine salivary glands were strongly immunopositive for S-100 protein. Mucous cells the palatine salivary glands were constantly negative for all tested proteins. Positive staining for α–actin and desmin were observed in the myoepithelial cells, smooth muscle fibers of blood vessels in addition to intrinsic skeletal muscles of tongue and soft palate. Desmin was Immunohistochemical Distribution Of S-100 Protein And . Amin Hassanin et al., Kafr El-Sheikh Vet.Med.J. Vol. 1 No.1 (2003) 237 expressed in stratum granulosum of keratinized epithelium and supranuclear region of lingual salivary glands. Vimentin was always present in connective tissue cells and nerve bundles in both tongue and soft palate. These results revealed a tissue specific distribution of the tested proteins in bovine tongue and soft palate; that highlight for the use of these proteins as markers for many morphological and pathological aspects. INTRODUCTION S-100 protein is classified into a group of calcium binding proteins (Isobe et al., 1982; Kahn et al, 1991) with a low molecular weight of about 10-24 kDa (Fano et al., 1995) that are important in intracellular calcium metabolism (McNutt, 1998). S-100 protein was thought to regulate diverse groups of cellular functions including cell growth, energy metabolism, contraction and intracellular signal transduction (Zimmer et al., 1995). It was first isolated in the brain and it has long been considered as specific to the nervous system (Bock, 1978). However, subsequent studies revealed presence of S-100 protein in other tissues as human testis (Haimoto et al., 1987), human epidermis (Rowden et al., 1985), bovine testis (Amselgruber et al., 1992; Cruzana et al., 2003) and a wide variety of organs and tissues including lymph nodes, spleen, thymus, pancreas, salivary and mammary glands (Nakajima et al., 1982; Turusov, 1990; Momotani et al., 1993; Nagasao et al., 2002). Antibodies against S-100 are widely used in diagnosis of human tumors (Turusov, 1990) and have been shown to be a useful marker for the epidermal Langerhans cells (Takahashi and Immunohistochemical Distribution Of S-100 Protein And . Amin Hassanin et al., Kafr El-Sheikh Vet.Med.J. Vol. 1 No.1 (2003) 238 Nakano, 1989). Cytoskeletal proteins desmin and vimentin are intermediate filaments (about 10 nm in diameter) and microfilaments actin (diameter up to 7 nm) are normal constituents in the cells but they have a high degree of cell lineage specificity (Weber and Osborn, 1982; Weber and Geisler, 1984). -actin is a contractile protein present in muscle and some non-muscular tissues (Skalli et al., 1986) and detected in myoepithelial cells (Zedda and Farina, 1998). Desmin is normally present in muscular tissues (skeletal, smooth and cardiac muscles) and its expression is highly specific for muscle and their tumors (Azumi et al., 1988). Vimentin is present in most of mesenchymal cells (Azumi and Battifora, 1987), it was localized in epidermal fibroblasts in human skin (Rappersberger et al., 1990) and expressed in smooth muscles of blood vessels (Gabbiani et al., 1981). Little information about the expression of S-100 protein and cytoskeleton proteins in bovine tissues are available. The present study describes the exact localization and differential distribution of S-100 protein and cytoskeletal proteins (-actin, desmin and vimentin) in bovine tongue and soft palate. MATERIALS AND METHODS