Peritubular Contractile Cells in Testis and Epididymis of the Dog, Canis lupus familiaris

Abstract

Contractile cells surrounding the tubular system of the mammalian testis and epididymis are supposed to contribute to the initial transport of spermatozoa from the testis to epididymis. Testicular peritubular smooth muscle cells have been characterised in detail especially in rodents and humans. The aim of our study was to assess the distribution of peritubular contractile cells of the canine tubuli seminiferi, rete testis channels, ductuli efferentes, and ductus epididymidis by immunohistochemistry and transmission electron microscopy and to classify these cells with respect to their possible physiological function. The entire tubular system of the canine testis and epididymis is surrounded by contractile cells expressing smooth muscle actin, smooth muscle myosin and desmin, which are enveloped, at least partly, by a basal lamina. Some contractile cells of the tubuli seminiferi, rete channels, and efferent ducts and sometimes also single peritubular cells of the ductus epididymidis express vimentin. Contractile cells of seminiferous tubules and efferent ducts represent an intermediate cell type exhibiting characteristics of both smooth muscle cells (SMC) and myofibroblasts, those of rete channels stellate myofibroblasts, and those of the ductus epididymidis SMC. Differences in structure and arrangement of the contractile cells between seminiferous tubules, rete channels, efferent ducts, and ductus epididymidis suggest different functions. Myofibroblasts and contractile cells similar to them could be mainly responsible for the maintenance of an appropriate tissue turgor, whereas contraction of SMC of the ductus epididymidis might cause propulsion of spermatozoa by peristaltic waves. Myofibroblasts, smooth muscle cells, sperm transport, immunohistochemistry, electron microscopy

Comparative expression of laminin and smooth muscle actin in the testis and epididymis of poultry and rabbit

“…Nevertheless, the interductal smooth muscles were very few in rabbits. aSMA was also detected in the epididymis of other mammals such as rat (Francavilla et al 1983), llama (Rodri 9guez et al 1999, bull (Alkafafy 2005), and dog (Egger and Witter 2009).…”

“…In addition, aSMA has been recently shown to signal the beginning of blood-testis barrier formation rather than its completion (Holt et al 2004). Several immunohistochemical studies have also detected aSMA in the adult testis of rat (Palombi et al 1992), monkey (Schlatt et al 1993), ram , bull Abd-Elmaksoud 2005) and human (Holstein et al 1996) as well as in the epididymis of rat (Francavilla et al 1983), bull (Alkafafy 2005), and dog (Egger and Witter 2009). Recently, aSMA has been additionally detected in the testis of Japanese quail (van Nassauw et al 1993;Aire and Ozegbe 2007), domestic fowl (Maretta and Marettova 2004;Aire and Ozegbe 2007), mallard duck and turkey (Aire and Ozegbe 2007) and rabbit (Banks et al 2006).…”

Histological, Micrometrical and Histochemical Studies on the Testes of Large White Yorkshire Pig (Sus scrofa domesticus)

“…in bull,Egger et al (2009) in dog andShitarjit et al (2018) in Zovawk pig.The tunica albuginea and interstitial tissue surrounding the seminiferous tubules consisted mainly of collagen, elastic and reticular fibres. Our findings are in accordance with the earlier reports ofAhmed (2005);Gofur et al (2008) in bull,Shukla et al (2013) in horse andShitarjit et al (2018) in Zovawk pig.…”

In Vitro Spermatogenesis; Past, Present, and Future

“…A s represents the stem cell pool and same characteristics may remain among few A pr cells as well. Larger chains of A al (8,16,32) differentiate toward the Type A1 spermatogonia and then give rise to A2, A3, A4, Intermediate and B, respectively. These differentiated spermatogonia divide in a synchronize manner and found at specific stages of the seminiferous epithelial cycle.…”

“…Spermiation is the last process involving breakage of the structures and bonds anchoring mature spermatids to Sertoli cells in order to release spermatozoa into the tubule lumen. Peristaltic waves created by peritubular smooth muscle cells help to move spermatozoa and testicular fluids through the seminiferous tubules to the epididymis [16]. This ~10-16 days migration through epididymis helps sperm to attain motility and natural fertilization capacity up to a certain extent [17,18].…”