Association of segmentation of the epididymal interstitium with segmented tubule function in rats and mice

Abstract

The epithelium of the epididymal tubule has different biological functions in different regions of the tubule. Each region is further organized into lobules or intra-regional segments surrounded by connective tissue septa (CTS). Epididymal segmentation has received little direct attention, yet there is considerable evidence that expression of mRNA and protein often begins or ends precisely at the CTS border of a segment. How such 'on-off' regulation occurs coincident with the passing of the tubule from one segment to the next is unknown. This study examined the segmentation of epididymides in rats and mice. The average adult Sprague-Dawley rat and C57BL/6 mouse caput, corpus and cauda epididymides has seven, two and four, and three, one and two segments, respectively. The apoptosis response of the caput epididymal epithelium to deprivation of lumicrine factors 24 h after efferent duct ligation in rats and the epididymal expression of a marker protein, ␤-galactosidase, in mice were segmented precisely. This validated both at a general response and at a specific protein level that many epididymal functions are regulated within segments. Blue dextran (molecular weight 20 000) and erythrocine red (molecular weight 880) dyes infused into the interstitial space of specific segments by micropuncture were retained by the CTS of the segments. In similar micropuncture experiments, [ 3 H]H 2 O (molecular weight 18) was able to diffuse into an adjacent segment relatively freely whereas [ 14 C]polyethylene glycol (molecular weight 4000) could not. These studies indicate that the interstitium of intra-regional segments is organized into different physiological compartments and that these compartments play a role in regulating the epididymal epithelium.

Androgens and the male reproductive tract: an overview of classical roles and current perspectives

“…Microarray analysis of the genes differentially expressed in the Wolffian ducts of male rat fetuses from mothers treated with the weak anti-androgen linurion, from days 12 to 21 of pregnancy, has demonstrated significant changes in mRNA expression of insulin-like growth factor 1 (IGF-1), bone morphogenetic protein (BMP), fibroblast growth factor (FGF) and epidermal growth factor (EGF) signaling pathways, consistent with a disruption of paracrine interactions between mesenchymal and epithelial cells in the testosterone-mediated development of the Wolffian duct. A significant decrease in Ar transcript levels in the Wolffian duct at embryonic day 21 is also observed in this experimental model, confirming that Ar mRNA expression is induced by androgens in this structure (51).…”

Why are epididymal tumours so rare?

“…79 b-galactosidase (b-Gal) with neutral pH activity is constitutively expressed in the caput and corpus epididymidal epithelium of young adult rats and mice. 81 It is located in the supranuclear region of principal cells in the initial segment, but not in adjacent caput regions, 82 and in the corpus. 42 It is not known if this b-Gal is identical to SABG in oncogene-induced senescence.…”

Dynamic expression pattern and subcellular localization of the Rhox10 homeobox transcription factor during early germ cell development

“…5A). Each segment expresses distinct sets of genes that permit each segment to harbor luminal fluid with different contents, which, in turn, may endow each segment with distinct functional properties (Turner et al 2003, Cornwall 2009). To examine whether RHOX10 protein is expressed in the epididymis, we performed immunohistochemical analysis on adult epididymis sections with the RHOX10 antiserum.…”

“…5C, double arrows). The expression of many genes in the epididymis depends on testicular factors traveling through the luminal fluid from the efferent ducts (Turner et al 2003, Cornwall 2009). To test whether this was the case for Rhox10, we performed a unilateral castration experiment, which prevents testicular factors from entering the epididymis on one side while the other side is left intact.…”