Expression of Occludin in Canine Testis and Epididymis

Abstract

Tight junctions (TJ) in inter-Sertoli junctional areas and epididymal epithelia are important for the formation of blood-testis barrier (BTB) and blood-epididymal barrier (BEB). In this study, the expression of occludin, an integral member of the TJ, was verified in canine testis and epididymis. Both low molecular weight (MW) (25-28 kDa) forms as well as high MW (68-72 kDa) forms of occludin were detected in the testis and epididymis using Western blot. The relative amount of the high MW forms of occludin vs low MW forms was higher in the testis than in the epididymis. Some difference in the composition of different MW forms of occludin was found along the segments of epididymis, suggesting the possible correlation between cellular composition of occludin proteins and paracellular permeability of epithelia along the epididymal tubule. In the testis, intense occludin immunoreactivity was found in the basally located inter-Sertoli junctional area. Diffused immunoreactivity of occludin was also found in the cytoplasm of Sertoli cells. A similar pattern of zonula occludens-1 immunoreactivity was found in the cytoplasm of Sertoli cells, suggesting that occludin was not confined to the inter-Sertoli junctional areas and that subcellular localization of occludin in the Sertoli cells was dynamically regulated during spermatogenesis in canine testis. In the epididymis weak immunoreactivity was found in the apical sides and cytoplasm of epithelial cells.

Effect of local scrotal heating on the expression of tight junction‐associated molecule Occludin in boar testes

“…Our results for Occludin (both mRNA and protein) were similar with these findings (Chen et al., ; Cai et al., ; Liu & Li, ). Furthermore, previous studies confirmed that immunoreactivity of Occludin was found in the cytoplasm of Sertoli cells and localized at tight junctions strands in dog and rabbit testes (Gye, ; Yoon, Park, Nah, & Gye, ). Cai et al.…”

Sterility and Gene Expression in Hybrid Males of Xenopus laevis and X. muelleri

“…Occludin which was upregulated about 9 times more in X. muelleri compared to hybrids has an important role in the formation of tight junctions surrounding Sertoli cells and seminiferous tubules in mammals [51] and salamanders [52]. Goosecoid is an important transcription factor during early development of Xenopus and was found to be about 8 times overexpressed in X. muelleri relative to hybrids.…”

Blood-testis barrier and spermatogenesis: lessons from genetically-modified mice

“…By postnatal day 23 and in adult mice, these bands are present in all tubules at all stages of seminiferous epithelial cycle 97. As in mice, Ocln is also detected at all stages of the seminiferous epithelial cycle in dogs and Korean wild rabbits Lepus coreanus 9899. However, in rats, Ocln protein expression is stage-specific, expressing heavily in Sertoli cells in seminiferous tubes of all stages except stage VIII, where it is not detectable by immunostaining 9699.…”