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Effects of age and gonadal steroids on the localization of antigen presenting cells in the epididymis of the male chicken, Gallus domesticus.

The goal of this study was to localize antigen presenting cells (APC), which may play roles in defense against pathogens and fertility, and examine the effects of age and gonadal steroids on their population in the rooster epididymis. Healthy White Leghorn male birds (immature 60-day-old birds; matured 150-, 330-, and 550-day-old), and immature birds treated with testosterone propionate (TP) or estradiol benzoate (EB) for 3 or 6 days were used. Cryostat sections of the epididymis and ductus deference were immunostained for Ia to identify APC. RT-PCR was performed to confirm the expression of major histocompatibility complex class II (MHC class II) mRNA in the epididymis. Ia+ cells were localized in the surface epithelium and subepithelial layer of the ductules and occasionally in the luminal content of the epididymis and ductus deference. RT-PCR analysis confirmed expression of MHC class II mRNA in the epididymis, ductus deferens, testis, and spleen. The frequency of Ia+ cells in the subepithelial layer was significantly greater in the proximal efferent ductules than in the other two types of ductules in the epididymis of 550-day-old birds. Although there were no significant differences in the frequencies in the subepithelial layer of the proximal efferent ductules between 60- and 150-day-old birds, the frequencies were significantly greater in 330- and 550-day-old birds than in 60-day-old birds. The frequencies of Ia+ cells in the ductus deferences was increased in the 150-day-old birds compared with the 60-day-old birds, with a larger increase in 330- and 550-day-old birds. The Ia+ cell frequency was significantly increased by EB-injection, but not by TP-injection, on Days 3 and 6 of injection compared with Day 0. These results suggest that the population of APC in the epididymis increases with age after sexual maturation, and estrogen may be one of the factors involved in induction of Ia+ cells.

Age Factors↗

Functional maturation of the epididymis in the rat.

Weight, histological and biochemical changes in the rat epididymis were investigated during prepubertal, pubertal and postpubertal periods. The phase of most rapid growth of the epididymis commenced at 21 days and extended to 60 days of age; this period corresponded closely to the onset of androgen production at 3 weeks and stabilization of the leydig cell number at 60 days. Histological differentiation in the caput epididymis started before sperm entry and was complete in the cauda only several days after the spermatozoa had appeared. The presence of appreciable quantities of glycerophosphorylcholine (GPC) and sialic acid in the epididymis of 21-day-old rats suggested inherent secretory ability of the epididymal epithelium. The concentrations of GPC, sialic acid, phospholipids and glycogen in the epididymis gradually increased with age, but each came under the influence of androgen at a different age. There was no evidence to suggest that the presence of spermatozoa has a stimulatory effect on the epididymis. Maximal secretory activity of the epididymis became established only by 90 days of age.

Animals↗

Expression, localization, and regulation of inhibitor of DNA binding (Id) proteins in the rat epididymis.

The epididymis is the site in which spermatozoa are matured and stored. Regional differences along the epididymis are essential for the establishment of the microenvironment required for germ cell maturation. Inhibitor of DNA binding (Id) proteins are transcription factors that modulate the functions of basic helix-loop-helix (bHLH) transcription factors and act by binding to and sequestering bHLH proteins; the latter act to regulate cellular proliferation and differentiation. The objectives of this study were to determine the mRNA expression and the immunocytolocalization of Id1, Id2, Id3, and Id4 in the epididymis of adult rats and to determine the Id3 protein expression profile in orchidectomized and in aged animals. We found that, at the mRNA level, Id proteins are expressed in a unique, region-specific manner along the epididymis. Id1 immunoreactivity is specific to myoid cells; the presence of Id2 is observed in clear cells, myoid cells, and in the apical region of principal cells. Id3 immunoreactivity is essentially confined to the nuclei of principal cells and myoid cells, whereas Id4 is observed mainly in myoid and narrow cells. Thus, Ids are localized to different cell types and are differentially expressed, at both the mRNA and protein levels, along the epididymis. Expression of Id3 is differentially regulated in response to orchidectomy along the epididymis. The fact that these regulators of gene expression are expressed in this manner may provide some insight into the differential expression of other genes that lead to region-specific differences along the epididymis, a hallmark of this tissue.

Animals↗

Expression of the cystic fibrosis transmembrane conductance regulator (CFTR) mRNA in normal and pathological adult human epididymis.

The pathogenesis of the aberrant development of the male genital tract (epididymis, vas deferens and seminal vesicles) seen in patients with congenital bilateral absence of the vas deferens (CBAVD) is still unclear. Since men with CBAVD carry mutations in the cystic fibrosis transmembrane conductance regulator gene (CFTR), it is likely that CFTR mRNA of the translated protein plays a major role in the pathogenesis of CBAVD. The aim of this study was to compare the pattern of expression of CFTR mRNA in epididymides of men with CBAVD and other types of obstruction (post-vasectomy and post-inflammatory) with that of normal non-obstructed adult epididymis. Epididymal biopsies were obtained at the time of microsurgical epididymal sperm aspiration procedures or during vaso-epididymostomy reanastomosis. A normal epididymis was obtained from an orchiectomy specimen. After standard processing for in situ hybridization, tissue sections were hybridized with CFTR gene-probe labelled by incorporation of digoxigenin-dUTP. After hybridization the signal was detected by an alkaline phosphatase-tagged antidigoxigenin antibody. CFTR mRNA was clearly identified in the columnar epithelium of the normal adult epididymis and vas deferens and the signal intensity was greatest in the most proximal regions of the caput epididymis. In contrast, men with genital tract obstructions due to CBAVD or post-vasectomy or post-inflammatory obstructions, had sloughing of the epithelial cells lining the lumen and as a consequence CFTR mRNA expression was lacking. In one subject (post-vasectomy obstruction), some residual caput epididymal epithelium was preserved and CFTR mRNA was detected. The abundant CFTR mRNA expression in the proximal caput of the epididymis and vas deferens under normal conditions strongly favours the hypothesis of an early obstructive process in the pathogenesis of CBAVD. The absent or severely reduced activity of CFTR protein affects the ionic exchange and fluid content within the epididymal lumen and this, in turn, can lead to excessive viscosity of the epididymal fluid, sloughing of epithelial cells expressing CFTR and further reduction in the amount of CFTR activity. As a consequence, variable segments of the epididymis and the vas deferens may be blocked and progressively obliterated. The epididymal lumen obstruction could also sustain the anatomical defects by not allowing testosterone to exert a local action on the mesonephric duct.

Adult↗

[Studies on expression and location of VEGF protein in rat testis and epididymis].

In order to investigate the function of vascular endothelial growth factor (VEGF) in the male reproductive system, we examined the expression and localization of VEGF protein in adult rat testis and epididymis with the immunohistochemical method and PAS stain and western blots. The results showed that the VEGF protein (about 45 kD) was present in the rat testis and epididymis. The VEGF immunoreactive particles were localized in the cytoplasm of spermatids, Sertoli cells and Leydig cells with negatively stained nuclei. The expression pattern of the spermatids was different in the 14 stages of epithelial cycle, and the strong immunopositive reaction was mainly in the forming/formed acrosome of round/elongated spermatids and spermiogenic residual bodies. In the epididymis, the region-specific and cell-specific expression and localization of VEGF protein was shown in the epididymal epithelium. In the initial segment, the VEGF protein was presented in the whole epithelial cells and the immunoreactive particles were localized in the supranuclear region of the cells. Except for a few principal cells and basal cells, counter-staining of PAS stain proved that the immunoreactive cells were clear cells in the caput, corpus, and cauda epididymis. And the immunoreactive particles were localized in the different region of the cytoplasm of clear cells, some were in the supranuclear region, some were filled in the whole cytoplasm, and some were secreted out of the cells along the free border. The positive acrosomes of the spermatozoa were only seen in the lumen of the proximal epididymis. No expression was detected in the interstitial blood vessels and the capillaries of the testis and epididymis. The present results indicate that VEGF protein may play an important role in the process of the spermatogenesis and spermiogenesis, especially in the acrosomal developing process. VEGF may also be related to the sperm maturation in the epididymis.

Animals↗

Biochemical observations on the protein and nucleic acid metabolism of the rat testis and epididymis after treatment with low doses of alpha-chlorohydrin.

A biochemical study was made on the effects of low doses of alpha-chlorohydrin on the protein and nucleic acid metabolism of the rat testis and epididymis. RNA and protein levels were decreased both in the testis and epididymis. The DNA content of the testis and epididymis did not change after exposure of the animals to the drug. The reduced concentrations of RNA and protein were closely paralleled by the increased activity of proteinase (protein hydrolyzing enzyme) and ribonuclease (RNA degrading enzyme) in the testis and epididymis. The gamma-glutamyl transpeptidase activity of both the testis and epididymis was also reduced indicating the slow transfer of amino acids across the cell membranes of testis and epididymis and thus low protein synthesis. The DNAase levels of rat testis and epididymis did not show any appreciable change in response to the alpha-chlorohydrin treatment. These studies indicate that although there may not be any histological damage in the tissue the metabolic pathways may become defective much earlier before any visible morphological change is discernible.

Animals↗

[Ultrasonographic investigations in diagnosis of congenital malformations of epididymis in cases of azoospermia].

Between 1984-1991 in 28 patients referred for the surgical treatment for the reason of obstruction of epididymis outlet ducts there was a suspicion of a congenital epididymis malformation put after the physical examination. The ultrasound examination of the scrotum which was performed in all cases revealed the proper view of the epididymis in 5 cases, the proper head of the epididymis with the broad tubules and the lack of the corpus and cauda in 19 cases and in 4 cases the residual head of the epididymis located in region of the upper pole of the testis. Intraoperative findings were consistent with the ultrasound results in 75.0% of cases. The highest consistency between the ultrasonographic and intraoperative findings was found in the cases with the proper view of the head of the epididymis with agenesis of corpus and cauda. In 32.1% of cases malformations of epididymis and vas deferens were associated with the malformations of the urinary tract.

Epididymis↗

Mouse epididymal sperm contain active P450 aromatase which decreases as sperm traverse the epididymis.

Recently we reported that mouse germ cells in the testis contain active P450 aromatase (P450arom), the enzyme that converts androgens to estrogens. This finding suggested that germ cells have the ability to produce estrogen. Further studies have shown that germ cells in the testis of several species contain P450arom. The goal of this study was to determine if epididymal sperm contain P450arom and if P450arom activity in sperm changes during traversion of the epididymis in the adult mouse. P450arom was localized in sperm present in the efferent ductules and epididymis by immunocytochemistry using an antiserum generated against purified human placental cytochrome P450arom. P450arom immunostaining in sperm was most prominent in sperm located in the proximal caput epididymis, decreased as sperm traversed the corpus epididymis, and was only slightly apparent in sperm in the cauda epididymis. The immunolocalization of P450arom in epididymal sperm was supported by the measurement of P450arom activity in sperm by the 3H2O assay. We found that P450arom activity in sperm significantly decreases as sperm traverse the epididymis. Based upon these observations, we conclude that sperm can synthesize estrogen and that the synthesis of estrogen by sperm present in the efferent ductules and caput epididymis could be important in the process of sperm maturation.

Animals↗

Androgen regulation of molecular forms of beta-D-glucuronidase in the mouse epididymis: comparison with liver and kidney.

The expression and androgen regulation of beta-glucuronidase molecular forms were examined in mouse epididymis, liver, and kidney. Two-dimensional polyacrylamide gel electrophoresis performed under nondenaturing conditions showed that, compared to liver and kidney, which contain four microsomal (M1-M4) and a major lysosomal (L) form of beta-glucuronidase, the epididymis revealed regional differences and tissue specificity in the expression of the various molecular forms of the enzyme. Only the lysosomal form (pI 5.4-6.1) is present in the caput epididymidis while the corpus/cauda contains the lysosomal form, the free X form (pI 5.9-6.3) and the four microsomal forms (X form complexed with egasyn). Mutant mice that lack egasyn have no microsomal forms in the distal epididymis. In epididymal fluid, the lysosomal form is found throughout the epididymis, whereas the X form appears only in the corpus/cauda epididymidis. Sodium dodecyl Sulfate (SDS)-gel electrophoresis and western blot analysis of immunoprecipitated beta-glucuronidase revealed only one band corresponding to the L form (apparent molecular weight 74 kDa) in the caput epididymidis and two bands in the corpus/cauda (apparent molecular weights 73 and 75 kDa), corresponding to L and X forms, respectively. Castration of mice led to the suppression of the regional differences in the appearance of X and M forms in the epididymis. Testosterone supplementation to castrated mice restored the characteristic electrophoretic pattern of beta-glucuronidase in the caput epididymidis. In the liver and kidney, castration has no effect on the expression of the molecular forms, whereas androgen treatment induced the X form in the kidney. Histochemical localization of beta-glucuronidase confirmed the region specificity seen in the epididymis and in addition revealed cell specificity in the expression of beta-glucuronidase. These results indicate that beta-glucuronidase shows tissue specificity and, in the case of the epididymis, region and cell specificity. In addition, the enzyme in the different tissues responds differentially to androgens.

Animals↗

The mRNAs for the steroid 5 alpha-reductase isozymes, types 1 and 2, are differentially regulated in the rat epididymis.

The enzyme steroid 5 alpha-reductase (EC 1.3.1.22) catalyzes the conversion of testosterone to its more potent form, dihydrotestosterone (DHT), in many androgen-sensitive target tissues. In the epididymis, the 5 alpha-reduced metabolites of testosterone, DHT and 5 alpha-androstan-3 alpha, 17 beta-diol (3 alpha-diol), are considered the primary regulators of epididymal structure and function. Two rat 5 alpha-reductase transcripts, designated types 1 and 2, have been identified. Our laboratory has previously characterized the endocrine and developmental regulation of the 5 alpha-reductase type 1 mRNA in the rat epididymis. However, regulation of the type 2 mRNA has not been investigated. Thus, we undertook to characterize the longitudinal distribution of the steady state 5 alpha-reductase type 2 mRNA as well as the effects of development and of unilateral efferent duct ligation on its expression in the rat epididymis. To contrast the regulation of the type 2 5 alpha-reductase isozyme mRNAs in the rat epididymis, these data have been compared with those previously obtained for the type 1 mRNA and enzyme activity. An analysis of the longitudinal distribution of the type 2 transcript along the epididymis revealed that its mRNA was expressed predominantly in the proximal caput region of the tissue. This regional distribution pattern differed markedly from the patterns previously described for the type 1 mRNA and enzyme activity. Surprisingly, a segment-by-segment analysis showed that epididymal 5 alpha-reductase type 2 mRNA levels were not altered as a function of increasing postnatal age. Again, this result was in marked contrast to the important changes in 5 alpha-reductase type 1 mRNA and enzyme activity that have been reported to occur during puberty in the rat. In the final experiment, the effect of unilateral efferent duct ligation revealed that 5 alpha-reductase type 2 mRNA levels increased in the initial segment of the ligated side but remained unchanged in the rest of the tissue; this was in marked contrast to the dramatic decrease (>60%) in type 1 mRNA levels observed specifically in the initial segment of the epididymis. Taken together, these experiments demonstrate that 5 alpha-reductase type 1 and type 2 mRNAs are differentially regulated in the rat epididymis. Moreover, this is the first report of a tissue in which the mRNAs for the steroid 5 alpha-reductase isozymes are regulated differently.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗

Distribution of leukocytes in the epithelium and interstitium of four regions of the Lewis rat epididymis.

BACKGROUND: Leukocytes expressing different surface markers were studied in four regions of the epididymis of Lewis rats. Cells resembling lymphocytes or monocytes had been described in the epididymis, but previous studies differed as to their nature and immunologic significance. METHODS: Frozen sections were immunocytochemically stained with monoclonal antibodies W3/25, OX-8, OX-42, and RLN-9D3, which are directed toward markers on CD4+ cells, CD8+ cells, macrophages, and B lymphocytes, respectively. The concentration of stained cells in the epithelium and interstitial tissue of the initial segment, caput, proximal cauda, and distal cauda regions was determined by a procedure based on the optical disector method. RESULTS: CD4+ leukocytes were present in greater concentration than CD8+ cells or macrophages in both the epithelium and interstitial tissue of all four regions. In the epithelium, the concentration of CD8+ leukocytes was greater than that of macrophages in the initial segment, caput, and distal cauda. In the interstitium, however, the concentration of macrophages exceeded that of CD8+ cells in both parts of the cauda. Macrophages and T lymphocytes were generally present in greater concentrations in the interstitium than in the epithelium, especially in the more proximal parts of the epididymis. In contrast to T cells, B lymphocytes were not detected in the interstitium or epithelium of any of part of the epididymis, despite prominent staining of B cells in other locations. CONCLUSIONS: The epididymal epithelium of the Lewis rat contains many T lymphocytes, which may correspond to 'halo' cells. CD4+ leukocytes predominate in all regions of the epididymis. The interstitium may function as a reservoir of leukocytes for the epithelial compartment. The epididymis is not normally a site for local immunoglobulin synthesis.

Animals↗

beta-Hexosaminidase immunolocalization and alpha- and beta-subunit gene expression in the rat testis and epididymis.

beta-hexosaminidase is an essential lysosomal enzyme whose absence in man results in a group of disorders, the G(M2) gangliosidoses. beta-hexosaminidase activity is many times higher in the epididymis than in other tissues, is present in sperm, and is postulated to be required for mammalian fertilization. To better understand which cells are responsible for beta-hexosaminidase expression and how it is regulated in the male reproductive system, we quantitated the mRNA expression of the alpha- and beta-subunits of beta-hexosaminidase and carried out immunocytochemical localization studies of the enzyme in the rat testis and epididymis. beta-hexosaminidase alpha-subunit mRNA was abundant and differentially expressed in the adult rat testis and epididymis, at 13- and 2-fold brain levels, respectively. In contrast, beta-subunit mRNA levels in the testis and epididymis were 0.3- and 5-fold brain levels. During testis development from 7-91 postnatal days of age, testis levels of alpha-subunit mRNA increased 10-fold and coincided with the appearance of spermatocytes and spermatids in the epithelium; in contrast, beta-subunit mRNA was expressed at low levels throughout tests development. In isolated male germ cells, beta-hexosaminidase alpha-subunit expression was most abundant in haploid round spermatids, whereas the beta-subunit mRNA was not detected in germ cells. Within the epididymis both alpha- and beta-subunit mRNA concentrations were highest in the corpus, with 1.5-fold and 9-fold initial segment values, respectively. Light microscopic immunocytochemistry revealed that beta-hexosaminidase was localized to Sertoli cells and interstitial macrophages in the testis. In the epididymis, beta-hexosaminidase staining was most intense in narrow cells in the initial segment, principal cells in the caput and proximal corpus, and clear cells throughout the duct. Electron microscopic immunocytochemistry revealed that beta-hexosaminidase was predominantly present in lysosomes in Sertoli and epididymal cells. The cellular and regional specificity of beta-hexosaminidase immunolocalization suggest an important role for the enzyme in testicular and epididymal functions.

Animals↗

Expression and regulation of LRP-2/megalin in epithelial cells lining the efferent ducts and epididymis during postnatal development.

Low density lipoprotein receptor-related protein-2/megalin (LRP-2) is a receptor belonging to the low density lipoprotein receptor family that mediates endocytosis and lysosomal degradation of a variety of ligands including apolipoprotein J (Apo J)/clusterin/SGP-2. LRP-2 has been shown to be expressed regionally in the adult rat epididymis. In this study, we describe the pattern of expression of LRP-2 in the efferent ducts and epididymis during postnatal development of the rat and examine the role of testicular luminally derived substances on its expression. The expression of LRP-2 was analyzed immunocytochemically in tissues of normal animals ranging in age from postnatal day 7-90 and in 15-day-old efferent-duct-ligated animals sacrificed at later ages. In the efferent ducts, LRP-2 expression, appearing as a dense band on the apical surface of the nonciliated epithelial cells, was noted as early as day 7, well before the entry of sperm, Sertoli-cell-derived secretory products, and high levels of androgens. Efferent duct ligation studies further revealed that expression under this condition was comparable to controls at all later ages examined, suggesting that the factor regulating its expression was not a luminally derived testicular substance. In normal untreated animals, LRP-2 expression was not apparent at any of the ages examined in the proximal initial segment of the epididymis. By comparison, the distal initial segment, although having no LRP-2 expression from 7-15 days, showed expression in principal cells by day 21 which intensified at days 29 and 39. However, by day 49 and at later ages (56 and 90), LRP-2 immunoreactivity over principal cells became spotty or with weak or moderate reactivity in some cells and none in others. LRP-2 expression in the intermediate zone, proximal caput, corpus, and cauda regions also appeared in principal cells by day 21, intensified at days 29 and 39 and persisted as such at all later ages examined, correlating with high levels of androgens shown to occur by day 39. Although LRP-2 expression in the distal caput region was evident in principal cells at days 21 and 29, it became spotty with weak, moderate, or absent reactivity over principal cells at all later ages. These data suggest that LRP-2 expression is under the influence of both stimulatory and region-specific inhibitory factors. Analysis of 15-day-old efferent-duct-ligated animals at all later ages examined revealed that there was no change in LRP-2 expression along the entire epididymis, suggesting that both the stimulatory and inhibitory factors are not luminally derived testicular substances. The observed pattern of LRP-2 expression in all regions of the epididymis, except the distal caput region, was similar to that described for Apo J internalization by principal cells during postnatal development, showing a correlation between LRP-2 expression and its ligand, Apo J. In summary, LRP-2 expression in the epididymis undergoes region-specific changes during postnatal development and appears to be influenced by both stimulatory and inhibitory factors.

Animals↗

Developmental expression of the Yf subunit of glutathione S-transferase P in epithelial cells of the testis, efferent ducts, and epididymis of the rat.

BACKGROUND: Glutathione S-transferases (GSTs) are a family of isozymes that catalyze the conjugation of the tripeptide, glutathione, to various electrophilic compounds. The major GST in the pi class is GST-P, a homodimer of the Yf subunit, also known as Yp or rat subunit 7. This subunit is found in high concentrations in the epididymis and has recently been immunolocalized within epithelial principal and basal cells of the epididymis. METHODS: In the present study we examine in groups of animals fixed in Bouin's fixative for light microscopy and in 4% paraformaldehyde and 0.5% glutaraldehyde in phosphate buffer for electron microscopy, the pattern of immunostaining for the Yf subunit of GST-P in the testis, efferent ducts and epididymis at various ages after birth. RESULTS: In the epididymis, on postnatal days 7 and 15, an immunoperoxidase reaction was localized exclusively to the apical and supranuclear regions of the undifferentiated columnar epithelial cells of the entire epididymis. By day 21, a dramatic change had taken place. In the initial segment, intermediate zone and proximal caput epididymidis, the columnar cells showed a distinct checkerboard-like staining pattern with cells ranging from being intensely reactive to unreactive. In contrast, principal cells of the distal caput, corpus, and proximal cauda epididymidis were weakly reactive. By day 28 the ratio of reactive to unreactive cells in the initial segment, intermediate zone, and proximal caput epididymidis was higher. By day 39, the differentiated columnar epithelial cells, referred to as principal cells, took on their adult staining pattern in the proximal and middle areas of the initial segment as well as the corpus and proximal cauda epididymidis where they were slightly reactive; in the distal initial segment they were strongly reactive. At day 49, principal cells in the intermediate zone and proximal caput became intensely reactive, while showing a distinct checkerboard-like staining pattern in the distal caput; similar observations were made for tissues taken from 56 and 90-day-old animals. Basal cells also showed a variable staining pattern in the different epididymal regions as a function of age. At day 21, when they first appeared, they were unreactive except for an occasional reactive cell in the corpus region. At day 28, only in the corpus epididymidis were many basal cells seen to be reactive. By day 39 the more numerous basal cells of the corpus and proximal cauda epididymidis were intensely reactive and remained so into adulthood. In these regions, basal cells appeared as dome-shaped cells (days 21, 28, 39), but then gradually flattened out and exhibited processes (days, 49, 56, adults) which collectively appeared to envelop the base of each tubule in a mesh-like network. The change in basal cell shape in each region coincided with the arrival of fluid and spermatozoa into the lumen (corpus day 49, proximal cauda day 56). In other epididymal regions, basal cells at day 28 were mostly unreactive. However, there was a gradual increase in the number of reactive basal cells of these regions between day 39 and 56. CONCLUSIONS: The present results thus demonstrate a dramatic change in the immunostaining pattern for the Yf subunit of GST-P during postnatal development for both principal and basal cells along the epididymis. Such results suggest that different factors play a role in the regulation of the expression of the Yf protein, not only in different epididymal regions, but also in different cell types during postnatal development.

Animals↗

Extracellular matrix abnormalities in testis and epididymis of XXSxr ("sex-reversed") mice.

Sex-reversed (Sxr) is a duplication of the sex-determining region of the Y chromosome, which gets transposed to a paternal X chromosome. Chromosomally female (XX) zygotes that receive this XSxr chromosome develop as apparent males. Previous work on XXSxr mice (called pseudomales) showed extracellular matrix (ECM) ultrastructural abnormalities in the epididymis and testis. This study examined the biochemical nature of these abnormalities. More hydroxyproline (an indicator of collagen) was noted in the pseudomale testis and epididymis compared to normal male tissues. Western blot analysis showed increased collagen IV in the pseudomale testis and epididymis. In both the hydroxyproline and collagen IV studies, the epididymis was found to contain higher levels of these substances than the testis for both genotypes. There also appeared to be increased messenger RNA for tissue inhibitor of metalloproteinases (Timp), a regulator of collagen, in the pseudomale testis. Data from these studies seem to indicate that the XXSxr genotype influences ECM deposition and/or turnover and exerts a direct genetic influence on the development of the testis and epididymis. According to the existing paradigm of mammalian sexual development, the epididymis is expected to be normal in the presence of adequate androgenization and independent of chromosomal and genetic sex. The results presented here differ from what would be predicted by this paradigm.

Animals↗

Polyol pathway along the bovine epididymis.

During the epididymal transit, male gametes acquire new surface proteins necessary for their fertilizing ability. We have previously shown that membranous vesicles, called epididymosomes, interact with sperm surface within the epididymal fluid allowing transfer of some proteins to different subcellular compartments of spermatozoa. We previously showed that one of the major proteins associated with epididymosomes was an aldose reductase (gene: AKR1B5) and confirmed that aldose reductase is located in the epithelial cells bordering the intraluminal compartment of the epididymis. The present study shows that cytosolic aldose reductase activity was maximal in the proximal and middle segments of the epididymis and decreased in the distal epididymis. Western and Northern blot analysis confirmed the distribution pattern of aldose reductase and of the encoding mRNA. The optimal pH of epididymal aldose reductase was 6.0-6.5 when glucose was used as a substrate; this corresponds to the pH of the intraluminal epididymal fluid. In order to evaluate the possible involvement of sorbitol in sperm physiology, Western blot of tissue homogenates were probed with an anti-sorbitol dehydrogenase antibody. The amount of enzyme immunodetected was higher in the proximal and distal segments of the epididymis when compared to the amount detectable in the middle segment of the epididymis. Sorbitol dehydrogenase activity as well as the level of the encoding mRNA showed the same pattern of distribution. Furthermore, immunohistological studies using the anti-sorbitol dehydrogenase revealed that this enzyme was synthesized by the epididymal epithelial cells bordering the intraluminal compartment. Knowing the importance of sorbitol and fructose in sperm metabolism, we hypothesized that the polyol pathway is involved in the modulation of sperm motility within the epididymis.

Aldehyde Reductase↗

Association of increased type I collagen expression and relative stromal overgrowth in mouse epididymis neonatally exposed to diethylstilbestrol.

The aim of this study was to investigate the molecular changes that underlie morphological changes in the epididymis following neonatal exposure to potent synthetic estrogen, namely diethylstilbestrol (DES). Newborn male mice were subcutaneously injected with DES or endogenous estrogen, namely 17 beta-estradiol (E2) (5 microg/mouse/day), for the first 5 days. At the age of 2, 4, and 8 weeks, epididymides of the mice were dissected. Characteristic morphological abnormality, such as relative stromal overgrowth, was observed at the age of 2 weeks in the epididymis of DES-treated mice, but not in E2-treated mice. Microarray and real-time RT-PCR analyses revealed that the expression levels of procollagen type I alpha 1 (col1a1) and col1a2 genes were markedly upregulated at the age of 2 weeks in the epididymis of DES-treated mice in comparison with the control. Western blot analysis revealed that type I collagen protein expression level in epididymis of DES-treated mice was elevated at the age of 2 weeks. In situ hybridization analysis revealed that the signals of col1a1 mRNA were detected similarly throughout the stromal tissue of epididymis at the age of 2 weeks in control and DES- and E2-treated mice. The gene expression level of epididymal type III collagen (col3a1), which is found in many stromal connective tissues as well as type I collagen, did not change at the age of 2 weeks in all groups. These results suggest that the increased type I collagen expression is associated with the relative stromal overgrowth in the epididymis of DES-treated mice.

Animals↗

Metabolism and toxicity of trichloroethylene in epididymis and testis.

The widespread occupational exposure to trichloroethylene (TCE) led us to test the hypothesis that TCE causes toxicity in the male reproductive system. We also investigated mechanisms mediating the potential cytotoxic response. Mice were exposed to TCE (1000 ppm) by inhalation for 6 h/day for 5 days/week for a total of 19 days. Exposure after the first week was interspersed by a "weekend." To estimate internal exposure, we measured the TCE metabolites, trichloroacetic acid (TCA) and trichloroethanol (TCOH), in urine at Days 4, 9, 14, and 19. Urinary excretion of TCOH was significantly higher than TCA; levels of TCOH and TCA significantly increased by the second and third week, respectively. Cytochrome P450 2E1 (CYP2E1), an enzyme involved in TCE metabolism, was localized in the epididymal epithelium and testicular Leydig cells, and was found at higher levels in the former than the latter. Immunoblotting confirmed that CYP2E1 protein was present in greater amounts in epididymis than in testis. p-Nitrophenol hydroxylation, a CYP2E1 catalytic activity, was also higher in the epididymis than in the testis. Chloral, a major TCE metabolite, was generated in microsomal incubations at significantly higher levels in epididymis than in testis. Antibody inhibition of CYP2E1 reduced chloral formation, which was more pronounced in epididymis than in testis. After 4 weeks of TCE exposure, damage to the epididymis was manifested as sloughing of epithelial cells. These results indicated that TCE is metabolized in the male reproductive tract, leading to adverse effects that are more severe in the epididymis than in the testis.

Administration, Inhalation↗