Histological and immunohistochemical studies on the epididymal duct in the dromedary camel (Camelus dromedarius)

Abstract

This study was conducted to underscore the spatial distribution of some biologically active proteins within the epididymal duct in the dromedary camel. Paraffin-embedded sections from different regions of epididymis were stained by conventional histological techniques and by immunohistochemistry. A battery of primary antibodies against six proteins (S100, alpha smooth muscle actin [α-SMA], connexin-43 [Cx43], galactosyltransferase [GalTase], angiotensin converting enzyme [ACE], and vascular endothelial growth factor [VEGF]) were used. The epididymal epithelium consisted of five cell populations: principal, basal, apical, dark, and halo cells. The histochemical findings indicated the absence of binding sites for VEGF and Cx43. The principal cells (PCs) showed variable immunoreactivity (IR) for ACE, S100, and GalTase throughout the whole length of the duct. The apical surfaces of most PCs (at the caput) and some PCs (at the corpus) exhibited intense ACE-IR, whereas those at the cauda displayed alternating negative and strong immunostaining. Similarly, moderate S100-IR was found in cytoplasm and nuclei of all PCs at the caput, few PCs at the corpus, and several PCs alternating with negative PCs at the cauda. In contrast, only some PCs showed weak to strong GalTase-IR in different regions. Apart from negative to weak positive S100-IR, basal cells failed to show IR for all other proteins. Apical cells displayed strong IR for ACE, S100, and GalTase with some regional differences. The peritubular and vascular smooth muscle cells revealed strong α-SMA-IR in all regions. In conclusion, the spatial distribution of different proteins in camel epididymis showed similarities and differences to other mammalian species. The region-specific topographic distribution of different proteins and cell types might indicate that the caput and cauda are metabolically more active than that of the corpus.

Seasonal immunohistochemical reactivity of S-100 and α-smooth muscle actin proteins in the epididymis of dromedary camel,Camelus dromedarius

“…Immunohistochemical studies of S‐100 and α‐SMA proteins have been carried out in the epididymis of several mammalian species including the dromedary camel (Abd‐Elmaksoud, ; Abd‐Elmaksoud et al., ; Alkafafy, ; Alkafafy et al., ,b), and these proteins are reported to contribute to the physiology of spermatozoa and the epididymis (Alkafafy et al., ; Czykier, Zabel, Surdyk‐Zasada, Lebelt, & Klim, ; Ijiri, Merdiushev, & Gerton, ; Martinez‐Heredia, de Mateo, Vidal‐Taboada, Ballesca, & Oliva, ). However, a seasonal study on immunohistochemical localisation of these proteins in the camel epididymis has not been performed so far.…”

“…The S‐100 and α‐SMA proteins are considered biologically active proteins of the epididymis, because of their functional relevance in absorption, secretion and contractile activities (Alkafafy et al., ). The presence of S‐100 protein has been reported in many organs especially in the testis of several mammalian species including ram, boar, horse, dog and bull (Amselgruber, Sinowatz, & Erhard, ; Amselgruber, Sinowatz, Schams, & Lehmann, ) and buffalo (Cruzana et al., ); this has also been reported in the epididymis of donkey (Alkafafy, ), buffalo (Alkafafy et al., ) and camel (Alkafafy, Rashed, Emara, Nada, & Helal, ). α‐SMA is mainly found in cells that undergo contractile activities and is considered as a valuable marker for the differentiation of smooth muscle cells under normal and abnormal conditions (Skalli et al., ).…”

“…The sections were then incubated with primary antibodies for overnight in a humidified chamber at 4°C. Polyclonal rabbit S‐100 antibody (catalog number‐Z0311, Dako, Hamburg, Germany; this antibody cross‐reacts with S‐100‐equivalent protein in cat, horse, mouse, rat and swine, Alkafafy et al., ) was used at the dilution of 1:400 with 5% NGS in PBS. Monoclonal mouse α‐SMA antibody (catalog number‐M0851, Dako, Hamburg, Germany; this antibody cross‐reacts with α‐SMA‐equivalent protein in chicken, cow and rat, Alkafafy et al., ) was used at the dilution of 1:200 with 5% NGS in PBS.…”

Presence and Distribution of Urocortin and its Receptors in the Epididymis of Alpaca (Vicugna pacos)

“…Although the role of AMRCs was unknown, the following functions have been suggested: holocrine secretion (Martan and Risley, ), cooperation with the PCs in reabsorption of testicular fluid (Sun and Flickinger, ) and acidification of epididymal fluid (Kierszenbaum et al., ). UCN therefore like other substances (S100, angiotensin‐converting enzyme and galactosyltransferase) expressed in the AMRCs (Alkafafy et al., ) might influence the absorptive and secretory activities in the epididymis of camelids.…”

Histological and immunohistochemical investigations of ovarian interstitial glands during non‐breeding season in camels (Camelus dromedarius)

“…S100 was widely expressed in male reproductive organs such as testis and epididymis of different animals like rat, boar, ruminants, European bison, camel and human, suggesting secretory and absorptive function (Abd‐Elmaksoud, Shoeib, & Hany, ). Some reports demonstrate S100 was expressed in female reproductive organs like camel oviduct, suggesting its role in enhancing the contractility of smooth muscle cells (Alkafafy, Rashed, Emara, Nada, & Helal, ). S100 may also participate in the processes of transcytosis and cell contractility that help in cellular secretion (Czykier, Sawicki, & Zabel, ).…”