Quality and fertility of frozen ovine spermatozoa from epididymides stored at room temperature (18–25 °C) for up to 48 h post mortem

Role of the bovine PRAMEY protein in sperm function during in vitro fertilization (IVF)

Preferentially expressed antigen in melanoma (PRAME) is a cancer/testis antigen (CTA) that is predominantly expressed in normal male gonad tissues and a variety of tumors. PRAME proteins are present in the acrosome and sperm tail, but their role in sperm function is unknown. The objective of this study was to examine the function of the bovine Y-linked PRAME (PRAMEY) during spermatozoal capacitation, the acrosome reaction (AR), and fertilization. Freshly ejaculated spermatozoa were induced to capacitate and undergo AR in vitro. Western blotting results revealed a decrease in the PRAMEY protein in capacitated spermatozoa, and the release of the PRAMEY protein from the acrosome during the AR, suggesting its involvement in sperm capacitation and AR. IVF was performed using in vitro matured bovine oocytes and cauda epididymal spermatozoa either treated with PRAMEY antibody, rabbit IgG, or DPBS. Sperm-egg binding and early embryos were examined at 6 and 45 h post IVF, respectively. The number of spermatozoa that bound per oocyte was nearly two-fold greater in the PRAMEY antibody treatment group (34.4) when compared to both the rabbit IgG (17.6) and DPBS (18.1) controls (P < 0.01). Polyspermy rate in the antibody-treated group (18.9%) was three-fold greater than the rabbit IgG control (6.0%) (P < 0.01). The results indicate that PRAMEY may play a role in anti-polyspermy defense. This study thus provides the initial evidence for the involvement of the PRAME protein family in sperm function and fertilization.

Testicular Degeneration and Infertility following Arbovirus Infection

Arboviruses can cause a variety of clinical signs, including febrile illness, arthritis, encephalitis, and hemorrhagic fever. The recent Zika epidemic highlighted the possibility that arboviruses may also negatively affect the male reproductive tract. In this study, we focused on bluetongue virus (BTV), the causative agent of bluetongue and one of the major arboviruses of ruminants. We show that rams that recovered from bluetongue displayed signs of testicular degeneration and azoospermia up to 100 days after the initial infection. Importantly, testicular degeneration was induced in rams experimentally infected with either a high (BTV-1_IT2006)- or a low (BTV-1_IT2013)-virulence strain of BTV. Rams infected with the low-virulence BTV strain displayed testicular lesions in the absence of other major clinical signs. Testicular lesions in BTV-infected rams were due to viral replication in the endothelial cells of the peritubular areas of the testes, resulting in stimulation of a type I interferon response, reduction of testosterone biosynthesis by Leydig cells and destruction of Sertoli cells and the blood-testis barrier in more severe cases. Hence, BTV induces testicular degeneration and disruption of spermatogenesis by replicating solely in the endothelial cells of the peritubular areas unlike other gonadotropic viruses. This study shows that a naturally occurring arboviral disease can cause testicular degeneration and affect male fertility at least temporarily.IMPORTANCE During the recent Zika epidemic, it has become apparent that arboviruses could potentially cause reproductive health problems in male patients. Little is known regarding the effects that arboviruses have on the male reproductive tract. Here, we studied bluetongue virus (BTV), an arbovirus of ruminants, and its effects on the testes of rams. We show that BTV was able to induce testicular degeneration in naturally and experimentally infected rams. Testicular degeneration was caused by BTV replication in the endothelial cells of the peritubular area surrounding the seminiferous tubules (the functional unit of the testes) and was associated with a localized type I interferon response, destruction of the cells supporting the developing germinal cells (Sertoli cells), and reduction of testosterone synthesis. As a result of BTV infection, rams became azoospermic. This study highlights that problems in the male reproductive tract caused by arboviruses could be more common than previously thought.

Viability of ovine spermatozoa collected from epididymides stored at 18°-25°C for 48 hours post mortem

ABSTRACT The objectives of this study were to verify the time during which viable ovine spermatozoa could be recovered from the cauda epididymis kept at ambient temperature (18-25°C). Sperm collected in an artificial vagina (AV) were used as control. Spermatozoa samples were collected with an AV and from epididymis at 0 (G0), 6 (G6), 12 (G12), 24 (G24), and 48 (G48) hours post mortem. Total motility (TM), progressive motility (PM), hypo-osmotic membrane integrity test (HOST) and morphological changes were assessed. TM decreased (P<0.05) from 24 hours post mortem (70.0±1.9%) compared to AV (86.4±1.0%). PM decreased (P<0.05) from 12 hours after death (31.3±4.0%) compared to AV group (73.2±1.4%). The percentage of viable cells in HOST decreased (P<0.05) in the G48 (60.0±8.9%). Spermatozoa recovery was lower (P<0.05) 48 hours after death (2064.2±230.7 x 106 spermatozoa) compared to G0(2623.6±288.4 x 106 spermatozoa). In conclusion, under the conditions of this study, it would be possible to use epididymal spermatozoa recovered up to 24 hours after death for artificial insemination or in vitro fertilization; however, fertility trials are necessary to prove this hypothesis.

Seminal plasma proteomes and sperm fertility

During ejaculation, the spermatozoa are transported by the seminal plasma, a fluid resulting from secretions originating mainly from the prostate and the seminal vesicles in mammals. The interaction of the seminal plasma with spermatozoa induces binding of seminal proteins onto the sperm surface and membrane remodeling potentially impacting the sperm transport, survival and fertilizing ability in the female genital tract. The seminal plasma also contains peptides and proteins involved in the inflammatory and immune response of the female tract. Therefore the seminal plasma proteome has been investigated in a large range of taxa, including mammals, birds, fishes and insect species. The association of the seminal plasma with semen preservation or fertility identified proteic markers of seminal plasma function in domestic species. This review summarizes the current knowledge in seminal plasma proteomes and proteic markers of sperm preservation in animal species.