Microscopical Identification of Telocytes in the Fundic Stomach of African Catfish (Clarias gariepinus).

Clarias gariepinus catfish fundic stomach telocytes (TCs) were identified using light microscopy (LM), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and immunohistochemistry. For LM, histochemical, hematoxylin, and eosin staining, as well as toluidine blue-stained semithin sections, were employed. These approaches revealed characteristic morphological features that differentiated TCs, which possessed a cell body with a nucleus and a telopode. Specifically, mucosal TCs were identified beneath the epithelium, within the lamina propria, and dispersed throughout the secretory units of the fundic glands. There were also TCs in the submucosa, muscle bundles, and serosa. Their CD34 affinity was strong, as was their affinity for α-SMA, CD68, CD3, S100-protein, and CD21. Moreover, SEM and TEM revealed that TCs formed a three-dimensional network within the lamina propria. TCs consisted of a cell body and TPs, which included slender segments called podomeres and podoms; the presence of rough endoplasmic reticulum and secretory vesicles distinguishes podoms. Furthermore, TCs demonstrated direct contact with neuroendocrine cells and macrophages and were associated with epithelial and endocrine cells. TCs surrounded the gland and blood vessels. Telocytes' expression of CD68, CD3, and CD21 suggests they may regulate stomach immunology, emphasizing the need to explore their immune-related protein profiles.