The testes in horses are reproductive organs responsible for the production of sperm and the secretion of hormones such as testosterone. Located in the scrotum, the testes play a vital role in male fertility and reproductive behavior. They consist of seminiferous tubules where spermatogenesis occurs, and interstitial cells, also known as Leydig cells, which produce testosterone. The function and health of equine testes can be influenced by factors such as age, season, and overall health status. This page compiles peer-reviewed research studies and scholarly articles that explore the anatomy, physiology, and pathology of the testes in horses, providing insights into their role in equine reproduction and breeding management.
Koziorowska-Gilun M, Gilun P, Mietelska K, Kordan W.The key prerequisite for successful insemination is sperm characterized to have positive values for morphological and biological variables which are determined by, among others, effective antioxidant protection during the lifespan of sperm cells. This study evaluated the activity and relative abundance of mRNA for antioxidant enzymes in stallion testicular and epididymal tissues during breeding (n = 5) and non-breeding (n = 5) seasons. The activity of superoxide dismutase (SOD) was greater (P < 0.05) during the breeding season, in particular in the testes and the caput epididymis, ...
Janečka JE, Davis BW, Ghosh S, Paria N, Das PJ, Orlando L, Schubert M, Nielsen MK, Stout TAE, Brashear W, Li G, Johnson CD, Metz RP, Zadjali AMA....Dynamic evolutionary processes and complex structure make the Y chromosome among the most diverse and least understood regions in mammalian genomes. Here, we present an annotated assembly of the male specific region of the horse Y chromosome (eMSY), representing the first comprehensive Y assembly in odd-toed ungulates. The eMSY comprises single-copy, equine specific multi-copy, PAR transposed, and novel ampliconic sequence classes. The eMSY gene density approaches that of autosomes with the highest number of retained X-Y gametologs recorded in eutherians, in addition to novel Y-born and transp...
Bogle OA, Carrasco RA, Ratto MH, Singh J, Adams GP.The objectives of the study were to compare the presence and localization of ovulation-inducing factor (OIF)/nerve growth factor (NGF) in male reproductive organs and determine the abundance in ejaculates of species representative of both spontaneous and induced ovulators. We hypothesized that the protein is a widely conserved component of semen among mammals, but is most abundant in camelids. Immunohistochemical analysis was performed on tissues from the male reproductive system of llamas, rats, cattle, bison, elk, and white-tailed deer (n = 2 males/species), and the abundance of OIF/NGF in...
Beracochea F, Viera MN, Acevedo L, Santiago-Moreno J, Ungerfeld R.In most goat breeds, testosterone serum concentration and semen quality decrease during the nonbreeding season. However, bucks reproductive activity may be stimulated with the administration of equine chorionic gonadotropin (eCG). Therefore, the aim of this study was to determine whether the repeated administration of eCG stimulates the reproductive status of bucks during the nonbreeding season. The study was performed with 19 bucks that were assigned to a group that was treated with eCG (GeCG) and an untreated control group (GCon). The GeCG bucks received an initial dose of 800 IU of eCG (Da...
Gautier C, Schmidt K, Aurich J, Aurich C.The hypothesis in this study was continuous treatment of stallions with the GnRH agonist deslorelin inhibits reproductive functions. A 2-week pre-experimental period was followed by an 11-week deslorelin implant treatment. Stallions received 4.7 (D1, n = 7), or 18.8 mg deslorelin (D2, n = 5) or remained untreated (C, n = 5). Libido, sperm motility, membrane integrity, DNA fragmentation, estrogen receptors, basal plasma testosterone and Anti Muellerian hormone (AMH) concentrations were evaluated once weekly during the treatment period. The testosterone response to the GnRH agonist buserelin a...
Pozor M, Conley AJ, Roser JF, Nolin M, Zambrano GL, Runyon SP, Kelleman AA, Macpherson ML.Recently, anti-Müllerian hormone (AMH) was validated as a reliable marker of testicular damage caused by various chemotherapy drugs in humans and in mice. In horses, the reference values of AMH concentrations in normal stallions, during different seasons of a year, have been recently reported. However, this hormone was not evaluated in subfertile or infertile stallions with testicular damage. Therefore, the objective of this study was to investigate the effects of experimentally induced testicular degeneration on the concentration of AMH in stallions. Severe but transient testicular degenerat...
Scarlet D, Wulf M, Kuhl J, Köhne M, Ille N, Conley AJ, Aurich C.Anti-Müllerian hormone (AMH) has gained increasing interest as a biomarker for assessment of gonadal activity. The ability to predict the ovarian follicular reserve of prepubertal female horses (fillies) or to identify stallions with testicular pathologies already during their prepubertal life has not been analyzed so far. Both would help to select fertile horses and reduce costs associated with keeping animals. The objectives of the present study were to (1) assess AMH, LH, FSH, progesterone (females) and testosterone (males) dynamics in prepubertal horses from birth onwards and (2) determin...
Ellerbrock RE, Canisso IF, Lima FS, Shipley CF, Thompson DL, Conley AJ, Kline KH.The objectives of this study were to determine the concentrations of reproductive and metabolic hormones during the peripubertal period and to assess their relationship with testicular development and body fat deposition. Blood samples were collected from 23 healthy Standardbred colts every four weeks for twelve months. Colts were weighed monthly, and percent of body fat and testicular volume estimated by ultrasound. Onset of puberty was determined as the month when testosterone was two standard deviations above the previous mean. Plasma FSH, LH, leptin, estradiol-17β, androstenedione, IGF-1,...
Roels K, Smits K, Ververs C, Govaere J, D'Herde K, Van Soom A.In horse breeding, intracytoplasmic sperm injection (ICSI) has gained interest to obtain offspring from subfertile individuals. This paper presents a case report of a stallion with severe testicular degeneration. Semen analysis showed very low motility and 83.5% of detached heads. Histology of a testicular biopsy showed severely decreased spermatogenesis, while transmission electron microscopy of the sperm cells revealed no significant abnormalities. A total of 39 oocytes were fertilized by ICSI with frozen-thawed spermatozoa of this stallion: 25 oocytes with intact spermatozoa and 24 with det...
Robles M, Nouveau E, Gautier C, Mendoza L, Dubois C, Dahirel M, Lagofun B, Aubrière MC, Lejeune JP, Caudron I, Guenon I, Viguié C, Wimel L....Obesity is a growing concern in horses. The effects of maternal obesity on maternal metabolism and low-grade inflammation during pregnancy, as well as offspring growth, metabolism, low-grade inflammation, testicular maturation and osteochondrotic lesions until 18 months of age were investigated. Twenty-four mares were used and separated into two groups at insemination according to body condition score (BCS): Normal (N, n = 10, BCS ≤4) and Obese (O, n = 14, BCS ≥4.25). BCS and plasma glucose, insulin, triglyceride, urea, non-esterified fatty acid, serum amyloid A (SAA), leptin and adiponect...
Robles M, Dubois C, Gautier C, Dahirel M, Guenon I, Bouraima-Lelong H, Viguié C, Wimel L, Couturier-Tarrade A, Chavatte-Palmer P.Primiparous mares are known to produce smaller foals than multiparous mares. This difference seems to be partly explained by the reduced exchange surface and volume of the placental villi in primiparous compared to multiparous placentas. The effect of maternal parity on foals' post-natal growth, metabolism and sexual maturation, however, has been given little consideration. The objectives of this work were to analyse placental biometry and structure at term, growth of foals and yearlings, their metabolism and testicular maturation at one year of age. Twenty multiparous mares (M), aged over 6 y...
Ketchum CC, Larsen CD, McNeil A, Meyer-Ficca ML, Meyer RG.Chromatin remodeling during spermatogenesis culminates in the exchange of nucleosomes for transition proteins and protamines as an important part of spermatid development to give rise to healthy sperm. Comparative immunofluorescence analyses of equine and murine testis histological sections were used to characterize nucleoprotein exchange in the stallion. Histone H4 hyperacetylation is considered a key event of histone removal during the nucleoprotein transition to a protamine-based sperm chromatin structure. In the stallion, but not the mouse, H4 was already highly acetylated in lysine residu...
Lindström H, Peer SM, Ing NH, Mannervik B.Glutathione transferases (GSTs) comprise a superfamily of enzymes prominently involved in detoxication by making toxic electrophiles more polar and therefore more easily excretable. However some GSTs have developed alternative functions. Thus, a member of the Alpha class GSTs in pig and human tissues is involved in steroid hormone biosynthesis, catalyzing the obligatory double-bond isomerization of Δ-androstene-3,17-dione to Δ-androstene-3,17-dione and of Δ-pregnene-3,20-dione to Δ-pregnene-3,20-dione on the biosynthetic pathways to testosterone and progesterone. The human GST A3-3 is the ...
Sassot LN, Ragle CA, Farnsworth KD, Lund CM.The major objective of this study was to describe the use of morcellation for standing laparoscopic cryptorchidectomy in 30 client-owned horses. A second objective was to describe a laparoscopic-assisted standing scrotal technique for removal of a descended testis in unilateral cryptorchids. Morcellation for extraction of abdominal testes is effective, efficient, and well-tolerated. Morcellation enabled safe and straightforward extraction of testes from the abdomen through an approximately 13- to 20-mm incision using a 2-portal technique. No incisional or morcellator-related complications occu...
Legacki EL, Ball BA, Corbin CJ, Loux SC, Scoggin KE, Stanley SD, Conley AJ.Equine fetuses have substantial circulating pregnenolone concentrations and thus have been postulated to provide significant substrate for placental 5α-reduced pregnane production, but the fetal site of pregnenolone synthesis remains unclear. The current studies investigated steroid concentrations in blood, adrenal glands, gonads and placenta from fetuses (4, 6, 9 and 10 months of gestational age (GA)), as well as tissue steroidogenic enzyme transcript levels. Pregnenolone and dehydroepiandrosterone (DHEA) were the most abundant steroids in fetal blood, pregnenolone was consistently higher bu...
Costa GMJ, Avelar GF, Lacerda SMSN, Figueiredo AFA, Tavares AO, Rezende-Neto JV, Martins FGP, França LR.The establishment of proper conditions for spermatogonial stem cells (SSCs) cryopreservation and storage represents an important biotechnological approach for the preservation of the genetic stock of valuable animals. This study demonstrates the effects of different cryopreservation protocols on the survival rates and phenotypic expression of SSCs in horses. The cells were enzymatically isolated from testes of eight adult horses. After enrichment and characterization of germ cells in the suspension, the feasibility of several cryopreservation protocols were evaluated. Three different cryomedia...
Pricking S, Bollwein H, Spilker K, Martinsson G, Schweizer A, Thomas S, Oldenhof H, Sieme H.Accurate determination of the testes volume and prediction of the daily sperm output (DSO) is valuable information for reproductive management of a stallion. The aim of this study was to compare different methods for measuring the testes volume, including caliper, 2D and 3D ultrasound. Special emphasis was on feasibility of 3D volume analysis. First, 22 castrated testes were measured and derived volumes were compared with volumes determined via volume displacement in a graded cylinder with saline solution. Then, during the breeding season, testes sizes of 52 stallions were measured in vivo an...
Pozor M, Morrissey H, Albanese V, Khouzam N, Deriberprey A, Macpherson ML, Kelleman AA.The goal of this study was to investigate correlations between objective measures of testicular echotexture and histomorphometric attributes related to the histological composition of stallion testes. Fifty-four scrotal testes were obtained from three groups of stallions during routine castrations: colts <1 yr old (n = 18), young stallions 1-5 yrs old (n = 27), mature stallions > 5 yrs old (n = 9). In addition, two scrotal testes with degeneration, 16 retained inguinal and 10 retained abdominal testes were surgically obtained. Cross-sectional and longitudinal ultrasonograms were obt...
Ortiz-Rodriguez JM, Anel-Lopez L, Martín-Muñoz P, Álvarez M, Gaitskell-Phillips G, Anel L, Rodríguez-Medina P, Peña FJ, Ortega Ferrusola C.Testicular function is particularly susceptible to vascular insult, resulting in a negative impact on sperm production and quality of the ejaculate. A prompt diagnosis of testicular dysfunction enables implementation of appropriate treatment, hence improving fertility forecasts for stallions. The present research aims to: (1) assess if Doppler ultrasonography is a good tool to diagnose stallions with testicular dysfunction; (2) to study the relationship between Doppler parameters of the testicular artery and those of sperm quality assessed by flow cytometry and (3) to establish cut off values ...
Rijkenhuizen ABM, van der Harst MR.Standing laparoscopic castration without orchidectomy has been shown to be a reliable method of castration in animals with abdominal cryptorchidism, but it cannot be recommended as a method of castration in those with inguinal cryptorchidism or normal males. An alternative laparoscopic method for the castration of horses with descended testes was developed. Objective: To report the results of laparoscopy-assisted abdominal transection of the spermatic cord and a modified open method in the standing horse for castration of descended testes in unilateral abdominal cryptorchids. Methods: Descript...
Bracamonte JL, Thomas KL.To document laparoscopic cryptorchidectomy with a vessel-sealing device in dorsal recumbent horses. Methods: Retrospective study. Methods: Forty-three male horses. Methods: Food was withheld for 36 hours before horses were placed under general anesthesia and positioned in dorsal recumbency. One laparoscopic portal and 2 instrument portals were placed for the laparoscopic procedure. A third instrument portal was created in bilateral cryptorchid horses. A vessel-sealing device was used for hemostasis and transection of retained testes. Descended testes were removed via closed castration with pri...
Welsford GE, Munk R, Villagómez DA, Hyttel P, King WA, Revay T.Testicular feminization, an earlier term coined for describing a syndrome resulting from failure of masculinization of target organs by androgen secretions during embryo development, has been well documented not only in humans but also in the domestic horse. The pathology, actually referred to as androgen insensitivity syndrome (AIS), has been proposed to follow an X-linked recessive pattern of inheritance in some horse breeds already investigated. Affected individuals are characterized by a female phenotype but with a stallion genotype of 64,XY SRY+ constitution. We identified a Warmblood hor...
Zeng W, Alpaugh W, Stefanovski D, Schlingmann K, Dobrinski I, Turner RM.The study of spermatogenesis in the horse is challenging because of the absence of an in vitro system that is capable of reproducing efficient spermatogenesis and because of the difficulties and costs associated with performing well-controlled studies in vivo. In an attempt to develop novel methods for the study of equine spermatogenesis, we tested whether cells from enzymatically digested pre-pubertal equine testicular tissue were capable of de novo tissue formation and spermatogenesis following xenografting under the back skin of immunocompromised mice. Testes were obtained from normal pre...
Waddington B, Penitente-Filho JM, Neves J, Pinho RO, Chaya AY, Maitan PP, Silveira CO, Neves MG, Guimarães S, de Carvalho GR, Guimarães JD.This study was conducted to characterize the daily profile of testosterone secretion and its mean concentrations in the four seasons as well as to evaluate the semen characteristics and testicular biometry of Mangalarga Marchador stallions throughout the year in a tropical region. Three stallions were submitted to semen collections and evaluation of testicular biometry every 14 days along a year. Blood samples were collected once at the middle of each season, in a 20-min interval during 24 hr in order to evaluate the testosterone secretion profiles among seasons. Testosterone concentrations ...
Lee YS, Jung HJ, Yoon MJ.Putative markers for each specific germ cell stage can be a useful tool to study the fate and functions of these cells. Undifferentiated embryonic cell transcription factor 1 (UTF1) is a putative marker for undifferentiated spermatogonia in humans, rats and horses. The deleted in azoospermia-like (DAZL) protein is also expressed by differentiated spermatogonia and primary spermatocytes in several species. However, whether the expression patterns of these molecular markers are identical and applicable to donkeys remains to be elucidated. The objective of this study was to investigate the expres...
Robles M, Gautier C, Mendoza L, Peugnet P, Dubois C, Dahirel M, Lejeune JP, Caudron I, Guenon I, Camous S, Tarrade A, Wimel L, Serteyn D....Pregnant mares and post-weaning foals are often fed concentrates rich in soluble carbohydrates, together with forage. Recent studies suggest that the use of concentrates is linked to alterations of metabolism and the development of osteochondrosis in foals. The aim of this study was to determine if broodmare diet during gestation affects metabolism, osteoarticular status and growth of yearlings overfed from 20 to 24 months of age and/or sexual maturity in prepubertal colts. Methods: Twenty-four saddlebred mares were fed forage only (n = 12, group F) or cracked barley and forage (n = 12, group ...
Lee G, Jung H, Yoon M.The molecular markers for specific germ cell stages can be utilized for identifying, monitoring, and separating a particular stage of germ cells. The RNA-binding protein Lin28 is expressed in gonocytes of human fetal testes. The Lin28 expression is restricted to a very small population of spermatogonial cells in human, mice, and monkey. The main objective of this study was to investigate the expression pattern of Lin28 in stallion testes at different reproductive stages. Based on the presence or absence of full spermatogenesis and lumina in seminiferous tubules, the testicular samples were cat...
Jung H, Kim N, Yoon M.The main objective of this study was to evaluate the efficacy of an additional cryoprotectant in 10% dimethyl sulfoxide (DMSO) on cryopreserving germ cells from stallions at different reproductive stages. Testicular samples were obtained from pre-pubertal (1-1.5 yr, n=6) and post-pubertal (3-7 yr, n=5) stallions. Germ cells were isolated using a two-enzyme digestion procedure and cryopreserved in minimal essential medium alpha containing 10% fetal bovine serum and 10% DMSO with or without addition of trehalose (50, 100, or 200mM) or polyethylene glycol (PEG, 2.5, 5, or 10%). Viability, cell po...
Davolli GM, Ball BA, Esteller-Vico A, Claes AN, Canisso IF, Fedorka CE, Woodward EM, Troedsson MH, Squires EL.The GnRH antagonist, acyline, has not yet been investigated in the stallion. Our study aimed to: (1) evaluate the downregulation of the stallion hypothalamic-pituitary-gonadal axis by acyline through assessment of seminal parameters, testicular volume, and sexual behavior; (2) assess hormonal response of acyline-treated stallions to GnRH stimulation; and (3) verify reversibility after treatment. Stallions were assessed pretreatment and subsequently treated (every five days) for 50 days: acyline (n = 4; 330 μg/kg acyline) or control (n = 4, vehicle). The stallions were then monitored for 62...
Almeida J, Conley AJ, Mathewson L, Ball BA.Sertoli cells are essential in development of a functional testis. During puberty, Sertoli cell maturation can be characterized by a number of markers, including anti-Müllerian hormone (AMH) and its receptor (AMHR2), androgen receptor (AR), cyclin-dependent kinase inhibitor (CDKN1B), and connexin 43 (Cx43). In the present study, immunohistochemistry (IHC) and real-time quantitative polymerase chain reaction (RT-qPCR) were used to characterize changes in expression of AMH, AMHR2, AR, CDKN1B, and Cx43 in prepubertal, postpubertal, and adult equine testes. During puberty, AMH expression decrease...
Anton F, Morales C, Aguilar R, Bellido C, Aguilar E, Gaytán F.The existence of a physiological integration between the immune and endocrine systems has long been recognized. In spite of the abundant literature data on the presence of cells of the immune system in the testis, mast cells and eosinophil leukocytes have received little attention. We have studied the presence, distribution and numbers of mast cells and eosinophils in the testes of 12 mammalian species. Mast cells were frequently found in equine (stallion, ass and mule) and human testis, whereas eosinophils were nearly absent. On the contrary, eosinophils were abundant in the hare testis, whil...
Jung HJ, Song H, Yoon MJ.Deleted in azoospermia-like (DAZL) is used as a germ cell marker in several species, including mice, rats, pigs, rhesus monkeys, bulls, and humans. Our objectives with this study were to investigate DAZL expression in stallion germ cells by using immunofluorescence, immunocytochemistry, and western blotting, and to determine the effects of reproductive stage and breeding season on the DAZL-positive cell population in seminiferous tubule cross sections. Testes were obtained during routine castration procedures at a large animal clinic and routine field service castration. The reproductive stage...
Jung H, Song H, Yoon M.Putative markers have been discovered and are used to identify and separate certain lineage of spermatogonia. The KIT is a marker for differentiating spermatogonial stem cells in several species including mice and goats. The objectives of this study were (1) to investigate reproductive stage-dependent KIT expression patterns in stallions and (2) to identify spermatogonia subpopulations expressing KIT in stallion testes. To achieve these objectives, testicular samples were obtained during routine field castration of stallions. The reproductive stage of the stallions was classified as pre-pubert...
Eisenhauer KM, McCue PM, Nayden DK, Osawa Y, Roser JF.Stallion testes secrete large amounts of estrogens, but the cellular location of the enzyme that converts androgens to estrogens, cytochrome P450 aromatase, has not been determined. The goal of the present study was to immunocytochemically localize stallion testicular aromatase using a polyclonal antibody generated against human placental cytochrome P450 aromatase. Testes were obtained from 12 stallions from 2 to 23 years of age, during both the breeding and non-breeding seasons. Immunoreactivity was confined to the Leydig cells in all testes examined. No immunostaining was observed in the Ser...
Leme DP, Papa FO.Fifteen stallions of different breeds, age 3-11 years, had their right testicles evaluated by fine needle aspiration cytology (FNAC). Cytological analysis showed the following spermatogenic cell types: spermatogonia (1.6% +/- 1.1); spermatocyte I (3.4% +/- 2.2); spermatocyte II (0.8% +/- 0.7); early spermatids (25.5% +/- 9.5); late spermatids (37.0% +/- 9.3). Spermatozoal numbers were expressed as the spermatic index (SI = 31.5% +/- 8.5) and Sertoli cells were expressed as the Sertoli cell index (SEI = 20.9% +/- 17.0) (means +/- s.d). Identification of cell types was relatively easy and no imm...
Naden J, Amann RP, Squires EL.Puberty was studied using 15 colts of Quarter Horse phenotype. Total scrotal width was measured every 8 weeks from 48 to 96 weeks. Blood samples were taken from 8 colts at 8, 16 and 24 weeks and then every 4 weeks until 100 weeks to measure changes in LH, FSH and testosterone concentrations. Seminal collections were attempted monthly from 48 to 64 weeks and every 2 weeks thereafter until puberty resumed every 3rd day from 96 weeks for 15 ejaculates. For all collections, times to erection, mount and ejaculation and seminal characteristics were recorded. Age at puberty was defined as the first e...
Gracia-Calvo LA, Duque J, Balao da Silva C, Ezquerra J, Ortega-Ferrusola C.Acquired inguinal herniation is a very common condition in stallions, usually leading to unilateral or bilateral castration to prevent future recurrence. Recently, several surgical techniques such as the standing laparoscopic peritoneal flap hernioplasty (SLPFH) have been developed to avoid herniation recurrence and also preserve the breeding activity of high economic value stallions. However, studies on SLPFH lack more comprehensive and systematic data about reproductive-related adverse effects and outcomes. The aim of this study was to evaluate whether SLPFH of the internal inguinal rings pr...
Ball BA, Gravance CG, Wessel MT, Sabeur K.A testis-specific isoform of angiotensin-converting enzyme (ACE) has been identified in a number of mammalian species. The purpose of this study was to characterize the activity of ACE in equine spermatozoa, seminal plasma, and testis. Activity of ACE was determined in seminal plasma, ejaculated and epididymal spermatozoa from mature stallions as well as from pre- and postpubertal testis. The effect of addition of angiotensin II on equine sperm motility was also evaluated. The activity of ACE in detergent extracted sperm plasma membrane was approximately 13-fold higher than that detected in se...
Herrera-Luna CV, Scarlet D, Walter I, Aurich C.The aim of the present study was to characterise receptors for LH and FSH (LHR and FSHR, respectively) and aromatase in epididymal and testicular tissue from stallions of different ages (prepubertal, young, mature and old). Gene and protein expression were assessed by real-time quantitative polymerase chain reaction (real-time qPCR), immunohistochemistry and multiple immunofluorescence labelling. There were no differences in LHR mRNA expression in epididymal and testicular parenchyma in stallions of different age. In contrast, expression of FSHR and CYP19A1 in caput, corpus and cauda epididymi...
Squires EL, Todter GE, Berndtson WE, Pickett BW.Thirty-two stallions were used to determine the effect of anabolic steroids on reproductive function. Stallions were assigned to one of the four treatments: 1) .23 ml sesame oil/kg of body weight (BW; control, C); 2) 4.4 mg boldenone undecylenate/kg BW (4E); 3) 1.1 mg boldenone undecylenate/kg BW (1E) and 4) 1.1 mg nandrolone decanoate/kg BW (D). Injections were given at 3-wk intervals for 15 wk. Semen was collected every other day for 3 wk before the first injection and at the same frequency during d 85 through 105 (d 0 = day of first injection). Libido was assessed on the basis of reaction t...
Heninger NL, Staub C, Blanchard TL, Johnson L, Varner DD, Forrest DW.Apoptosis in testicular germ cells has been demonstrated in many mammalian species. However, little is known about the stallion (Equus caballus) and rates of apoptosis during spermatogenesis. Morphological and biochemical features of apoptosis reported in other species were used to confirm that the TdT-mediated dUTP Nick end labeling (TUNEL) assay is an acceptable method for identification and quantification of apoptotic germ cells in histological tissue sections from stallion testis. Seminiferous tubules from eight stallions with normal testis size and semen quality were evaluated according t...
Gautier C, Barrier-Battut I, Guénon I, Goux D, Delalande C, Bouraïma-Lelong H.Estrogen receptors ESR1, ESR2 and GPER are present on mature ejaculated horse spermatozoa, suggesting these cells as putative targets for estrogens. Indeed, spermatozoa are exposed to high level of estrogens during the transit in the male and female genital tracts but their roles are not investigated. So, we evaluated in vitro the role of 17β-estradiol during post-testicular maturations: regulation of motility, capacitation and acrosome reaction. Moreover according to the pseudo-seasonal breeder status of the stallion, we analyzed the putative seasonal variations in the presence of ESRs in sp...
Robles M, Nouveau E, Gautier C, Mendoza L, Dubois C, Dahirel M, Lagofun B, Aubrière MC, Lejeune JP, Caudron I, Guenon I, Viguié C, Wimel L....Obesity is a growing concern in horses. The effects of maternal obesity on maternal metabolism and low-grade inflammation during pregnancy, as well as offspring growth, metabolism, low-grade inflammation, testicular maturation and osteochondrotic lesions until 18 months of age were investigated. Twenty-four mares were used and separated into two groups at insemination according to body condition score (BCS): Normal (N, n = 10, BCS ≤4) and Obese (O, n = 14, BCS ≥4.25). BCS and plasma glucose, insulin, triglyceride, urea, non-esterified fatty acid, serum amyloid A (SAA), leptin and adiponect...
Braun J, Sakai M, Hochi S, Oguri N.The suitability of ejaculated and epididymal stallion spermatozoa for cooled storage (5 degrees C) and cryopreservation was examined in 5 ejaculates from each of 6 stallions and in spermatozoa recovered from the cauda epididymidis after castration of these stallions. The percentage of progressively motile spermatozoa, examined by subjective estimation (cooled samples) or by computerized analysis (frozen-thawed samples), was used as parameter. In ejaculated semen samples containing 5 and 25% seminal plasma in a skim milk glucose extender, the lower amount of seminal plasma supported spermatozoa...
Klonisch T, Steger K, Kehlen A, Allen WR, Froehlich C, Kauffold J, Bergmann M, Hombach-Klonisch S.We employed molecular and immunological techniques to investigate the expression of INSL3, a member of the insulin-like superfamily, in prepubertal testis, postpubertal testes exhibiting normal and disturbed spermatogenesis, and cryptorchid testes of male horses. In addition, the partial cDNA coding sequences of the equine homologue of the human relaxin/INSL3-receptor Lgr8 were determined. Nonradioactive in-situ hybridization with a cRNA probe for equine Insl3 and immunohistochemistry with a specific rabbit INSL3 antiserum localized Insl3 transcripts and immunoreactive INSL3 ligand to Leydig c...
Bogle OA, Carrasco RA, Ratto MH, Singh J, Adams GP.The objectives of the study were to compare the presence and localization of ovulation-inducing factor (OIF)/nerve growth factor (NGF) in male reproductive organs and determine the abundance in ejaculates of species representative of both spontaneous and induced ovulators. We hypothesized that the protein is a widely conserved component of semen among mammals, but is most abundant in camelids. Immunohistochemical analysis was performed on tissues from the male reproductive system of llamas, rats, cattle, bison, elk, and white-tailed deer (n = 2 males/species), and the abundance of OIF/NGF in...
Pozor MA, Muehlhaus J, King A, Macpherson ML, Troedsson MH, Bailey CS.The objective was to investigate the effects of pentoxifylline (PTX) on testicular perfusion and sperm production in stallions. In a preliminary study, six mature Miniature horse stallions were given 0, 8.5, or 17.0 mg/kg of PTX orally, twice daily, for 3 d. Total Arterial Blood Flow Rate (TABFR) was higher (P < 0.05) in all treated versus control stallions during and after treatment. Two months later (during the fall and winter), the same stallions received either 0 or 17 mg/kg of PTX orally, twice daily for 60 d. Resistance and pulsatility indices (RI and PI, respectively) decreased in PT...
Setchell BP, Cox JE.In 3 testes of 2 adult Pony stallions under halothane anaesthesia, catheters were inserted into a vein and a lymphatic vessel in the spermatic cord and into a vein on the surface of the testis. Lymph and venous blood were collected from the catheters in the cord and p-aminohippurate (2% w/v, 0 . 1 ml/min) was infused into the vein on the testis to determine blood flow by dilution. After 1 h, 6000 i.u. hCG was injected i.v. and collections continued for 45 min. The testes weighed 126-176 g. Lymph flow was 20-150 microliter/min before hCG and 100-270 microliter/min after hCG; the range of blood ...
Love CC, Kenney RM.A variety of testicular insults can induce changes in the structure of spermatozoal chromatin, resulting in spermatozoal DNA that is more susceptible to acid-induced denaturation. The degree of change in the DNA can be measured using the sperm chromatin structure assay (SCSA). The SCSA measures the relative amounts of single- and double-stranded DNA after staining with the metachromatic dye, acridine orange. Here we used a stallion model (n = 4) to study the effects of scrotal heat stress on spermatozoal DNA. This model was created by insulating stallion testes for 48 h and collecting sperm da...
Zhang FL, Zhang XY, Zhao JX, Zhu KX, Liu SQ, Zhang T, Sun YJ, Wang JJ, Shen W.Mongolian horses have been bred and used for labor and transport for centuries. Nevertheless, traits of testicular development in Mongolian horses have rarely been studied; particularly, studies regarding the transcriptional regulation characteristics of testicular development are lacking. In this paper, transcription specificity during testicular development in Mongolian horses is highlighted via a multispecies comparative analysis and weighted gene co-expression network analysis (WGCNA). Interestingly, the results showed that most genes were up-regulated in the testes after sexual maturity, ...
Ortega-Ferrusola C, Gómez-Arrones V, Martín-Cano FE, Gil MC, Peña FJ, Gaitskell-Phillips G, Da Silva-Álvarez E.Ultrasound technology has led to new lines of research in equine reproduction, and it has helped to greatly improve clinical diagnosis and reproductive outcomes in equine practice. This review aims to discuss the potential clinical uses and new approaches of ultrasonography in equine reproduction. Doppler modalities are usually used to evaluate the vascularization of the follicles, corpus luteum (CL), and the uterus in the mare for diagnostic purposes. Inclusion of Doppler ultrasound in artificial insemination and embryo transfer programs could improve the reproductive outcome of these techniq...
Johnson L, Tatum ME.The temporal appearance of seasonal changes in numbers of Leydig, Sertoli, and germ cells was evaluated to determine if seasonally increased daily spermatozoan production might be preceded by changes in numbers of either of two somatic testicular cells. A significant increase in numbers of spermatogonia and Sertoli cells preceded the significant increase in number of Leydig cells in the approaching breeding season. Seasonal changes in parenchymal weight and in numbers of Sertoli cells, Leydig cells, and germ cells were maximal in May and June. Numbers of A or B spermatogonia in June were 2.4 t...
Almahbobi G, Papadopoulos V, Carreau S, Silberzahn P.Two ultrastructurally distinct types of Leydig cells were observed in the equine testis. Whereas the adult testis exhibited both postpubertal and adult Leydig cells, the testis of the pubertal horse contained only the postpubertal type, and that of the aged horse contained only the adult type. However, Percoll-purified testicular preparations from pubertal, adult, and aged horses all exhibited two distinct Leydig cell populations. The quantitative distribution and the functional characteristics of these Leydig cell populations (ability to bind human chorionic gonadotropin [hCG] and increase of...
Jung Y, Yoon M.Endocrine, paracrine, and autocrine factors orchestrate the development and physiology of the stallion reproductive system. Oxytocin (OXT) is one of the critical endocrine, paracrine, and autocrine factors for the male reproductive system. Previous studies have investigated OXT receptor (OXTR) expression in testes and epididymides, including humans, marmosets, macaques, swine, and sheep. This study aimed to explore (1) OXTR localization in the testes and epididymides and (2) the seasonal modification of OXTR expression in the testes. Adult stallion testis and epididymis samples were prepared u...
Pozor MA, Macpherson ML, McDonnell SM, Nollin M, Roser JF, Love C, Runyon S, Thomas BF, Troedsson MH.The objective of this study was to determine whether an indenopyridine derivative RTI-4587-073(l) was a good candidate for male contraception in horses. We hypothesized that a single administration of RTI-4587-073(l) causes significant suppression of testicular function in stallions without affecting sexual behavior. Three Miniature horse stallions received a single dose of 12.5 mg/kg RTI-4587-073(l) orally (group "treated"), whereas three other Miniature horse stallions received placebo only (group "control"). Semen was collected and evaluated from all stallions twice a week for three baselin...
Nagata S, Miyake YI, Nambo Y, Nagamine N, Watanabe G, Tsunoda N, Taniyama H, Hondo E, Yamada J, Taya K.To examine the physiological role of inhibin in the stallion, a heterologous radioimmunoassay (RIA) based on a bovine RIA was validated and used to measure immunoreactive (ir)-inhibin concentrations in plasma and testicular homogenates. The bioactivity of equine testicular inhibin was also examined using an assay for suppression of FSH secretion from rat anterior pituitary cells. In addition, to identify the cell responsible for secreting testicular inhibin, the localisation of inhibin in the testis was investigated by an immunohistochemical method using a polyclonal antibody against (Tyr30)-p...
Bilińska B, Wiszniewska B, Kosiniak-Kamysz K, Kotula-Balak M, Gancarczyk M, Hejmej A, Sadowska J, Marchlewicz M, Kolasa A, Wenda-Rózewicka L.The purpose of this article was to summarize our results on the role of androgens and estrogens in human, rodent and equine testes and epididymides, in both, physiological and patological conditions, obtained in the space of the Solicited Project (084/PO6/2002) financially supported by the State Committee for Scientific Research during the last three years. Testosterone produced by Leydig cells of the testes is clearly the major androgen in the circulation of men and adult males of most mammalian species. However, androgen metabolites make up a significant fraction of total circulating steroid...
