Exploring type I interferon pathway: virulent vs. attenuated strain of African swine fever virus revealing a novel function carried by MGF505-4R

African swine fever virus represents a significant reemerging threat to livestock populations, as its incidence and geographic distribution have surged over the past decade in Europe, Asia, and Caribbean, resulting in substantial socio-economic burdens and adverse effects on animal health and welfare. In a previous report, we described the protective properties of our newly thermo-attenuated strain (ASFV-989) in pigs against an experimental infection of its parental Georgia 2007/1 virulent strain. In this new study, our objective was to characterize the molecular mechanisms underlying the attenuation of ASFV-989. We first compared the activation of type I interferon pathway in response to ASFV-989 and Georgia 2007/1 infections, employing both in vivo and in vitro models. Expression of IFN-α was significantly increased in porcine alveolar macrophages infected with ASFV-989 while pigs infected with Georgia 2007/1 showed higher IFN-α than those infected by ASFV-989. We also used a medium-throughput transcriptomic approach to study the expression of viral genes by both strains, and identified several patterns of gene expression. Subsequently, we investigated whether proteins encoded by the eight genes deleted in ASFV-989 contribute to the modulation of the type I interferon signaling pathway. Using different strategies, we showed that MGF505-4R interfered with the induction of IFN-α/β pathway, likely through interaction with TRAF3. Altogether, our data reveal key differences between ASFV-989 and Georgia 2007/1 in their ability to control IFN-α/β signaling and provide molecular mechanisms underlying the role of MGF505-4R as a virulence factor.

The MIR34B/C genomic region contains multiple potential regulators of multiciliogenesis

The MIR449 genomic locus encompasses several regulators of multiciliated cell formation (multiciliogenesis). The miR-449 homologues miR-34b/c represent additional regulators of multiciliogenesis that are transcribed from another locus. Here, we characterized the expression of BTG4, LAYN and HOATZ, located in the MIR34B/C locus using single-cell RNA-seq and super-resolution microscopy from human, mouse or pig multiciliogenesis models. BTG4, LAYN and HOATZ transcripts were expressed in both precursors and mature multiciliated cells. The Layilin/LAYN protein was absent from primary cilia, but it was expressed in apical membrane regions or throughout motile cilia. LAYN silencing altered apical actin cap formation and multiciliogenesis. HOATZ protein was detected in primary cilia or throughout motile cilia. Altogether, our data suggest that the MIR34B/C locus may gather potential actors of multiciliogenesis.

Unmanned aerial vehicles (UAVs) as a tool for hazard assessment: The 2021 eruption of Cumbre Vieja volcano, La Palma Island (Spain)

Monitoring for assessment of natural disasters, such as volcanic eruptions, presents a methodological challenge for the scientific community. Here, we present Unmanned Aerial Vehicles (UAVs) as a feasible, precise, rapid and safe tool for real time monitoring of the impacts of a volcanic event during the Cumbre Vieja eruption on La Palma Island, Spain (2021). UAV surveys with optical RGB (Red-Green-Blue), thermal and multispectral sensors, and a water sampling device, were carried out in different areas affected by the lava flow, including the upper volcanic edifice and the lava delta formed on the coastal fringe of the island. Our results have provided useful information for the monitoring of the advance of the lava flow and its environmental consequences during the volcanic emergency. Our data shows how La Palma island's growth, with the formation of a new lava delta of 28 ha and a total volume of lava injected into the sea of 5,138,852 m³. Moreover, our Digital Elevation Model (DEM) simulated, with a 70 % accuracy, the probabilistic simulation of the possible path followed by the lava flow in the vicinity of the fissure from which the magma emanates. In addition, significant changes of seawater physical-chemical parameters were registered in coastal surface waters by the in situ seawater samples collected with the automatic water sampling device of our UAV. The first meters of the water column, due to the instant evaporation of the seawater in contact with the hot lava, produce an increase of temperature and salinity of up to 4-5 °C and up to 5 units, respectively.

New Insights in the Interplay Between African Swine Fever Virus and Innate Immunity and Its Impact on Viral Pathogenicity

The continuous spread of African swine fever virus (ASFV) in Europe and Asia represents a major threat to livestock health, with billions of dollars of income losses and major perturbations of the global pig industry. One striking feature of African swine fever (ASF) is the existence of different forms of the disease, ranging from acute with mortality rates approaching 100% to chronic, with mild clinical manifestations. These differences in pathogenicity have been linked to genomic alterations present in attenuated ASFV strains (and absent in virulent ones) and differences in the immune response of infected animals. In this mini-review, we summarized current knowledge on the connection between ASFV pathogenicity and the innate immune response induced in infected hosts, with a particular focus on the pathways involved in ASFV detection. Indeed, recent studies have highlighted the key role of the DNA sensor cGAS in ASFV sensing. We discussed what other pathways may be involved in ASFV sensing and inflammasome activation and summarized recent findings on the viral ASFV genes involved in the modulation of the interferon (IFN) and nuclear factor kappa B (NF-κB) pathways.

TLR5 signalling is hyper-responsive in porcine cystic fibrosis airways epithelium

Excessive lung inflammation and airway epithelium damage are hallmarks of cystic fibrosis (CF) disease. It is unclear whether lung inflammation is related to an intrinsic defect in the immune response or to chronic infection. We aimed to determine whether TLR5-mediated response is defective in the CF airway epithelium. We used a newborn CF pig model to study intrinsic alterations in CF airway epithelium innate immune response. Airway epithelial cells (AECs) were stimulated with flagellin or lipopolysaccharide to determine responses specific for TLR5 and TLR4, respectively. We observed a significant increase in cytokine secretion when CF AECs were stimulated with flagellin compared to wild type (WT) AECs. These results were recapitulated when AECs were treated with an inhibitor of CFTR channel activity. We show that TLR5-signalling is altered in CF lung epithelium at birth. Modulation of TLR5 signalling could contribute to better control the excessive inflammatory response observed in CF lungs.

Airway Administration of Flagellin Regulates the Inflammatory Response to Pseudomonas aeruginosa

Excessive lung inflammation and airway epithelial damage are hallmarks of human inflammatory lung diseases, such as cystic fibrosis (CF). Enhancement of innate immunity provides protection against pathogens while reducing lung-damaging inflammation. However, the mechanisms underlying innate immunity–mediated protection in the lung remain mysterious, in part because of the lack of appropriate animal models for these human diseases. TLR5 (Toll-like receptor 5) stimulation by its specific ligand, the bacterial protein flagellin, has been proposed to enhance protection against several respiratory infectious diseases, although other cellular events, such as calcium signaling, may also control the intensity of the innate immune response. Here, we investigated the molecular events prompted by stimulation with flagellin and its role in regulating innate immunity in the lung of the pig, which is anatomically and genetically more similar to humans than rodent models. We found that flagellin treatment modulated NF-κB signaling and intracellular calcium homeostasis in airway epithelial cells. Flagellin pretreatment reduced the NF-κB nuclear translocation and the expression of proinflammatory cytokines to a second flagellin stimulus as well as to Pseudomonas aeruginosa infection. Moreover, in vivo administration of flagellin decreased the severity of P. aeruginosa–induced pneumonia. Then we confirmed these beneficial effects of flagellin in a pathological model of CF by using ex vivo precision-cut lung slices from a CF pigz model. These results provide evidence that flagellin treatment contributes to a better regulation of the inflammatory response in inflammatory lung diseases such as CF.

Intrinsic alterations in peripheral neutrophils from cystic fibrosis newborn piglets

BACKGROUND

The hallmark of the cystic fibrosis (CF) lung disease is a neutrophil dominated lung environment that is associated to chronic lung tissue destruction and ultimately the patient's death. It is unclear whether the exacerbated neutrophil response is primary related to a defective CFTR or rather secondary to chronic bacterial colonization and inflammation. Here, we hypothesized that CF peripheral blood neutrophils present intrinsic alteration at birth before the start of an inflammatory process.

METHODS

Peripheral blood neutrophils were isolated from newborn CFTR^+/+ and CFTR^-/- piglets. Neutrophils immunophenotype was evaluated by flow cytometry. Lipidomic and proteomic profile were characterized by liquid chromatography/tandem mass spectrometry (LC-MS/MS), intact cell matrix-assisted laser desorption/ionization mass spectrometry (ICM-MS) followed by top-down high-resolution mass spectrometry (HRMS), respectively. The ability of CF neutrophils to kill pseudomonas aeruginosa was also evaluated.

RESULTS

Polyunsaturated fatty acid metabolites analysis did not show any difference between CFTR^+/+ and CFTR^-/- neutrophils. On the other hand, a predictive mathematical model based on the ICM-MS proteomic profile was able to discriminate between both genotypes. Top-down proteomic analysis identified 19 m/z differentially abundant masses that corresponded mainly to proteins related to the antimicrobial response and the generation of reactive oxygen species (ROS). However, no alteration in the ability of CFTR^-/- neutrophils to kill pseudomonas aeruginosa in vitro was observed.

CONCLUSIONS

ICM-MS demonstrated that CFTR^-/- neutrophils present intrinsic alterations already at birth, before the presence of any infection or inflammation.

Novel dynamics of human mucociliary differentiation revealed by single-cell RNA sequencing of nasal epithelial cultures

The upper airway epithelium, which is mainly composed of multiciliated, goblet, club and basal cells, ensures proper mucociliary function and can regenerate in response to assaults. In chronic airway diseases, defective repair leads to tissue remodeling. Delineating key drivers of differentiation dynamics can help understand how normal or pathological regeneration occurs. Using single-cell transcriptomics and lineage inference, we have unraveled trajectories from basal to luminal cells, providing novel markers for specific populations. We report that: (1) a precursor subgroup of multiciliated cells, which we have entitled deuterosomal cells, is defined by specific markers, such as DEUP1, FOXN4, YPEL1, HES6 and CDC20B; (2) goblet cells can be precursors of multiciliated cells, thus explaining the presence of hybrid cells that co-express markers of goblet and multiciliated cells; and (3) a repertoire of molecules involved in the regeneration process, such as keratins or components of the Notch, Wnt or BMP/TGFβ pathways, can be identified. Confirmation of our results on fresh human and pig airway samples, and on mouse tracheal cells, extend and confirm our conclusions regarding the molecular and cellular choreography at work during mucociliary epithelial differentiation.

Tetrafunctional Block Copolymers Promote Lung Gene Transfer in Newborn Piglets

Tetrafunctional block copolymers are molecules capable of complexing DNA. Although ineffective in vitro, studies in mice have shown that the tetrafunctional block copolymer 704 is a more efficient lung gene transfer agent than the cationic liposome GL67A, previously used in a phase II clinical trial in cystic fibrosis patients. In the present study, we compared the gene transfer capacity of the 704-DNA formulation and a cationic liposome-DNA formulation equivalent to GL67A in a larger-animal model, the newborn piglet. Our results indicate an efficacy of the 704-DNA formulation well above one order of magnitude higher than that of the cationic liposome-DNA formulation, with no elevated levels of interleukin-6 (IL-6), taken as a marker of inflammation. Transgene expression was heterogeneous within lung lobes, with expression levels that were below the detection threshold in some samples, while high in other samples. This heterogeneity is likely to be due to the bolus injection procedure as well as to the small volume of injection. The present study highlights the potential of tetrafunctional block copolymers as non-viral vectors for lung gene therapy.

Modeling APC mutagenesis and familial adenomatous polyposis using human iPS cells

Mutations in the gene Adenomatous Polyposis Coli or APC appear in most sporadic cases of colorectal cancer and it is the most frequent mutation causing hereditary Familial Adenomatous Polyposis. The detailed molecular mechanism by which APC mutations predispose to the development of colorectal cancer is not completely understood. This is in part due to the lack of accessibility to appropriate models that recapitulate the early events associated with APC mediated intestinal transformation. We have established a novel platform utilizing human induced Pluripotent Stem cells or iPSC from normal or FAP-specific APC mutant individuals and evaluated the effect of the mutation in the cells before and after differentiation into intestinal organoids. In order to minimize genetic background effects, we also established an isogenic platform using TALEN-mediated gene editing. Comparison of normal and APC mutant iPSC revealed a significant defect in cell identity and polarity due to the presence of APC in heterozygosity as well as chromosomal aberrations including abnormal anaphases and centrosome numbers. Importantly, upon specification into intestinal progeny, APC heterozygosity was responsible for a major change in the transcriptional identity of the cells with dysregulation of key signaling pathways, including metabolic reprogramming, abnormal lipid metabolism and intestinal-specific cadherin expression. In conclusion, we have developed a novel iPSC/intestinal model of APC mutagenesis and provide strong evidence that APC in heterozygosity imparts a clear phenotypic and molecular defect, affecting basic cellular functions and integrity, providing novel insights in the earlier events of APC-mediated tumorigenesis.

Generation of a Stable Transgenic Swine Model Expressing a Porcine Histone 2B-eGFP Fusion Protein for Cell Tracking and Chromosome Dynamics Studies

Transgenic pigs have become an attractive research model in the field of translational research, regenerative medicine, and stem cell therapy due to their anatomic, genetic and physiological similarities with humans. The development of fluorescent proteins as molecular tags has allowed investigators to track cell migration and engraftment levels after transplantation. Here we describe the development of two transgenic pig models via SCNT expressing a fusion protein composed of eGFP and porcine Histone 2B (pH2B). This fusion protein is targeted to the nucleosomes resulting a nuclear/chromatin eGFP signal. The first model (I) was generated via random insertion of pH2B-eGFP driven by the CAG promoter (chicken beta actin promoter and rabbit Globin poly A; pCAG-pH2B-eGFP) and protected by human interferon-β matrix attachment regions (MARs). Despite the consistent, high, and ubiquitous expression of the fusion protein pH2B-eGFP in all tissues analyzed, two independently generated Model I transgenic lines developed neurodegenerative symptoms including Wallerian degeneration between 3–5 months of age, requiring euthanasia. A second transgenic model (II) was developed via CRISPR-Cas9 mediated homology-directed repair (HDR) of IRES-pH2B-eGFP into the endogenous β-actin (ACTB) locus. Model II transgenic animals showed ubiquitous expression of pH2B-eGFP on all tissues analyzed. Unlike the pCAG-pH2B-eGFP/MAR line, all Model II animals were healthy and multiple pregnancies have been established with progeny showing the expected Mendelian ratio for the transmission of the pH2B-eGFP. Expression of pH2B-eGFP was used to examine the timing of the maternal to zygotic transition after IVF, and to examine chromosome segregation of SCNT embryos. To our knowledge this is the first viable transgenic pig model with chromatin-associated eGFP allowing both cell tracking and the study of chromatin dynamics in a large animal model.

Interleukin-1 receptor antagonist mediates toll-like receptor 3-induced inhibition of trophoblast adhesion to endometrial cells in vitro

STUDY QUESTION

Is interleukin-1 receptor antagonist (IL-1RA) involved in the toll-like receptor 3 (TLR 3)-induced inhibition of trophoblast cells' adhesion to endometrial cells in vitro?

SUMMARY ANSWER

IL-1RA mediates the TLR 3-induced inhibition of trophoblast cells' adhesion to endometrial cells in vitro.

WHAT IS KNOWN ALREADY

It is well documented that endometrial TLR 3 activation leads to impairment of trophoblast binding to endometrial cells in vitro. IL-1RA is known as an anti-implantation factor, as its injection significantly reduced implantation rates in mice by an effect on endometrial receptivity.

STUDY DESIGN, SIZE, DURATION

Poly I:C was used as a TLR3 specific ligand and endometrial cells were either treated or not with Poly I:C (treated versus control) in vitro. IL-1RA was applied to block IL-1 signal transduction. IL-1RA was knocked down by Accell Human IL1RN siRNA. Flagellin was used to stimulate TLR 5. SP600125 (JNK) was applied to inhibit the mitogen-activated protein kinases (MAPK) pathway. BAY11 -7082 was used to inhibit the nuclear factor-κB (NF-κB) pathway. The experiments were performed in three replicates on three separate days.

PARTICIPANTS/MATERIALS, SETTING, METHODS

An in vitro assay was developed using RL95-2 (an endometrial cell line) and JAr (a trophoblast cell line) cells. Initially, the production of IL-1RA in RL95-2 cells in response to TLR 3 activation was measured. To determine whether the TLR 3-induced inhibition of trophoblast binding was mediated through IL-1RA: (i) we evaluated the effect of IL-1RA on the attachment of trophoblast cells to endometrial cells; (ii) we knocked down TLR3-induced IL-1RA gene expression by IL-1RA Small interfering RNA (siRNA) and evaluated trophoblast attachment to endometrial cells. Finally, to clarify through which pathway TLR 3-induced inhibition of trophoblast binding occurs: (i) activation of NF-κB and MAPK was detected by transfecting the cells with secreted placental alkaline phosphatase reporter plasmids bearing promoter sequences for each transcription factor; (ii) the inhibitors for NF-κB and MAPK were used to block signaling; (iii) it was then investigated whether addition of these inhibitors could restore the TLR 3-induced impairment of trophoblast attachment to the endometrial cells.

MAIN RESULTS AND THE ROLE OF CHANCE

Our results showed that addition of polyinosinic:polycytidylic acid (Poly I:C) to RL95-2 cells significantly increased the production of IL-1RA (P < 0.05). Addition of human recombinant IL-1RA to RL95-2 cells remarkably decreased the adhesion rate of trophoblast cells to endometrial cells (P < 0.05). In addition, suppression of TLR3-induced IL-1RA gene expression in RL95-2 cells significantly restored trophoblast cells attachment to endometrial cells in the presence of Poly I:C (P < 0.05). Only TLR3 and not TLR5 induced MAPK activation (P < 0.05). TLR3 ligation did not affect NF-κB activation. Of NF-kB and MAPK inhibitors, only MAPK's inhibitor could achieve restoration of spheroid adhesion to endometrial cells (P < 0.05).

LIMITATIONS, REASONS FOR CAUTION

This study has been only done in vitro. Future in vivo studies will confirm our data.

WIDER IMPLICATIONS OF THE FINDINGS

The findings of this study have a potential clinical application in introducing IL-1RA as one of the diagnostic infertility markers in the endometrium, which can affect the process of embryo adhesion at the time of implantation. Moreover, based on the novel data obtained in the current study, blocking and regulating the MAPK pathway by its inhibitors can be used as a new strategy to prevent and treat virus-induced infertility cases in ART techniques.

STUDY FUNDING/COMPETING INTEREST

This study was partially funded by a Marie Curie IIF-253948 grant to I.C. and was partially funded by the author's institutions. The authors have no conflict of interest to declare.

Activation of Toll-like receptor 3 reduces actin polymerization and adhesion molecule expression in endometrial cells, a potential mechanism for viral-induced implantation failure

STUDY QUESTION

Does activation of endometrial Toll-like receptor 3 (TLR 3) affect cell receptivity to trophoblast adhesion?

SUMMARY ANSWER

TLR 3 activation in vitro reduces the attachment of trophoblast cells to endometrial cells by altering the cell cytoskeleton and reducing the expression of adhesion molecules in human endometrial cells.

WHAT IS KNOWN ALREADY

It is well documented that the presence of an infection at the time of implantation can lead to implantation failure. The female reproductive tract recognizes invading micro-organisms through the innate pathogen recognition receptors such as the TLRs.

STUDY DESIGN, SIZE, DURATION

Poly I:C was used as a TLR 3-specific ligand and endometrial cells were either treated or not with Poly I:C (treated versus control) in vitro. The experiments were performed in three replicates on three separate days.

PARTICIPANTS/MATERIALS, SETTING, METHODS

An in vitro assay was developed using RL95-2 (a human endometrial cell line) and JAr (a human trophoblast cell line) cells. Initially, the percentage of attached JAr spheroids to RL95-2 was measured in response to TLR 3 activation. Next, actin polymerization in RL95-2 cells was assessed in response to TLR 2/6, 3 and 5 activation. Phalloidin was used to assess the mean fluorescence intensity of F-actin by flow cytometry or confocal microscopy. Secondly, the influence of TLR 2/6, 3 and 5 activation on the expression of cluster of differentiation 98 (CD98) and β3 integrin was determined. To further understand through which pathways the TLR 3-induced alterations occur, inhibitors were applied for Toll/interleukin-1 receptor domain-containing adaptor inducing interferon-beta (TRIF), myeloid differentiation primary response 88 (MYD88), mitogen-activated protein kinases (MAPK) and nuclear factor pathways.

MAIN RESULTS AND THE ROLE OF CHANCE

We observed that stimulation of TLR 3 in endometrial cells with different concentrations of Poly I:C led to a reduction in the percentage of trophoblasts attached to the endometrial cells in a dose-dependent manner (P < 0.05). This decrease was consistent in the Poly I:C treated group regardless of the co-incubation time (P < 0.05). In addition, our results demonstrated that actin polymerization and CD98 expression significantly decreased only in response to TLR 3 activation (P < 0.05). Activation of endometrial cells with TLR 2/6, 3 and 5 significantly reduced β3 integrin expression (P < 0.05). These alterations were shown to work via MYD88-MAPK pathways (P < 0.05).

LIMITATIONS, REASONS FOR CAUTION

This study has been performed in vitro. Future in vivo studies will be required in order to confirm our data.

WIDER IMPLICATIONS OF THE FINDINGS

This is a novel discovery which extends our current knowledge concerning diagnosis and treatment of viral-induced infertility cases.

STUDY FUNDING/COMPETING INTERESTS

This research was supported by the COST Action FA1201 (GEMINI) by granting a Short Term Scientific Mission and the Instituto de Salud Carlos III by granting Grant PI11/01645. The authors have no conflict of interest to declare.

The battle of the sexes starts in the oviduct: modulation of oviductal transcriptome by X and Y-bearing spermatozoa

BACKGROUND

Sex allocation of offspring in mammals is usually considered as a matter of chance, being dependent on whether an X- or a Y-chromosome-bearing spermatozoon reaches the oocyte first. Here we investigated the alternative possibility, namely that the oviducts can recognise X- and Y- spermatozoa, and may thus be able to bias the offspring sex ratio.

RESULTS

By introducing X- or Y-sperm populations into the two separate oviducts of single female pigs using bilateral laparoscopic insemination we found that the spermatozoa did indeed elicit sex-specific transcriptomic responses. Microarray analysis revealed that 501 were consistently altered (P-value < 0.05) in the oviduct in the presence of Y-chromosome-bearing spermatozoa compared to the presence of X-chromosome-bearing spermatozoa. From these 501 transcripts, 271 transcripts (54.1%) were down-regulated and 230 transcripts (45.9%) were up-regulated when the Y- chromosome-bearing spermatozoa was present in the oviduct. Our data showed that local immune responses specific to each sperm type were elicited within the oviduct. In addition, either type of spermatozoa elicits sex-specific signal transduction signalling by oviductal cells.

CONCLUSIONS

Our data suggest that the oviduct functions as a biological sensor that screens the spermatozoon, and then responds by modifying the oviductal environment. We hypothesize that there might exist a gender biasing mechanism controlled by the female.

Human trophoblast cells modulate endometrial cells nuclear factor κB response to flagellin in vitro

Background

Implantation is a complex process that requires a delicate cooperation between the immune and reproductive system. Any interference in the fine balance could result in embryo loss and infertility. We have recently shown that Toll-like receptor 5 activation results in a decrease of trophoblast cells binding to endometrial cells in an in vitro model of human implantation. However, little is known about the downstream signalling leading to the observed failure in implantation and the factors that modulate this immune response.

Methods and Principal Findings

An in vitro model of embryo implantation was used to evaluate the effect of trophoblasts and flagellin on the activation of NF-κB in endometrial cells and whether TLR5-related in vitro implantation failure is signalled through NF-κB. We generated two different NF-κB reporting cell lines by transfecting either an immortalized endometrial epithelial cell line (hTERT-EECs) or a human endometrial carcinoma cell line (Ishikawa 3-H-12) with a plasmid containing the secreted alkaline phosphatase (SEAP) under the control of five NF-κB sites. The presence of trophoblast cells as well as flagellin increased NF-κB activity when compared to controls. The NF-κB activation induced by flagellin was further increased by the addition of trophoblast cells. Moreover, blocking NF-κB signalling with a specific inhibitor (BAY11-7082) was able to restore the binding ability of our trophoblast cell line to the endometrial monolayer.

Conclusions

These are the first results showing a local effect of the trophoblasts on the innate immune response of the endometrial epithelium. Moreover, we show that implantation failure caused by intrauterine infections could be associated with abnormal levels of NF-κB activation. Further studies are needed to evaluate the target genes through which NF-κB activation after TLR5 stimulation lead to failure in implantation and the effect of the embryo on those genes. Understanding these pathways could help in the diagnosis and treatment of implantation failure cases.

Does Seminal Plasma PSP-I/PSP-II Spermadhesin Modulate the Ability of Boar Spermatozoa to Penetrate Homologous Oocytes In Vitro?

Low concentration (0.15 mg per million of spermatozoa) of seminal plasma-derived PSP-I/PSP-II spermadhesin heterodimer is able to preserve the viability of highly extended boar spermatozoa. Whether spermatozoa also keep their fertilizing capacity is not yet known. The present study evaluated the effect of exposing freshly extended and frozen-thawed boar spermatozoa (10 million/mL) to PSP-I/PSP-II (1.5 mg/mL) for 30 or 120 minutes on sperm characteristics and the outcome of in vitro penetration of immature (IM) and in vitro matured (IVM) homologous oocytes, aiming to identify this spermadhesin as a suitable modulator for sperm-handling protocols. Although exposure to the heterodimer improved sperm viability and motility without increasing the levels of sperm acrosome exocytosis in both freshly extended and frozen-thawed spermatozoa, this pretreatment did not affect sperm penetration rates or sperm numbers per oocyte when pretreated fresh spermatozoa were coincubated with IM or IVM oocytes compared with controls. When cryopreserved spermatozoa were tested, however, on IVM oocytes, already a 30-minute preincubation exposure to PSP-I/PSP-II showed a significant blocking effect on penetration rate (from 90% to 32%, P < .05) and on mean sperm numbers per oocyte (2.9 to 1.6, P < .05). To disclose the nature of this paradox, frozen-thawed spermatozoa were cleansed (by centrifugation in saline bovine serum albumin or through Percoll density gradient separation) and the procedure repeated. Oocyte penetration (but not number of spermatozoa per oocyte) increased (P < .05) when spermatozoa were cleansed with Percoll compared with either washed or unwashed controls (53% vs 13% vs 31%, respectively). In addition, the percentages of polyspermic oocytes remained lower than control (38.5% vs 68.7%, respectively; P < .05). In conclusion, the results confirm that exposure of fresh or frozen-thawed boar spermatozoa to a low dose of seminal PSP-I/PSP-II spermadhesin preserves sperm viability and motility in vitro. Although there was no obvious influence of the heterodimer on the capability of freshly extended boar spermatozoa to penetrate homologous oocytes (either IM or IVM), PSP-I/PSP-II exerted a deleterious effect when frozen-thawed spermatozoa were used to penetrate IVM oocytes. Such an effect of cryopreservation seems to a certain extent reversible, since cleansing of the sperm surface decreased, at least partially, this blocking effect, increasing both penetration and the monospermic rates.

Seminal plasma proteins as modulators of the sperm function and their application in sperm biotechnologies

Seminal plasma (SP) is known to play an important role in mammalian fertilization. However, the variability found in its composition among species, males and even fractions of the same ejaculate has made difficult to completely understand its effect in sperm function. Proteins are one of the major SP components that modulate sperm functionality. During the last years, intensive work has been performed to characterize the role of these proteins. They have been found to influence sperm capacitation, formation of the oviductal sperm reservoir and sperm-oocyte interaction. Sperm biotechnologies, such as sperm cryopreservation and flow cytometric sex-sorting, that involve a substantial dilution of the SP are detrimental to sperm quality. Attempts to improve the outcome of these biotechnologies include the restoration of SP, which has produced contradictory results. To overcome this variability, different research groups have proposed the application of isolated SP proteins. Herein, we will review the current knowledge in the role of the major SP proteins as modulators of sperm functionality. Furthermore, we will discuss the possible applications of the SP proteins in sperm cryopreservation and flow cytometric sex-sorting.

Analysis of the surgical activity in the Dermatology Department of Fuenlabrada University Hospital, Madrid, Spain, between 2005 and 2010: determination of the standard operating times

OBJECTIVES

To analyze the characteristics of the dermatologic surgery lists and to compare different indicators of surgical productivity.

MATERIALS AND METHODS

This was a retrospective, descriptive study of the routine surgical activity undertaken in the Dermatology Department of Fuenlabrada University Hospital, Madrid, Spain, between January 2005 and December 2010. Data about the procedures performed and about the surgical lists were analyzed and an analysis was made of operating room occupancy. Surgical productivity was analyzed using standard operating times (SOTs) and surgical scheduling adequacy values (SA1 and SA2). Variables were recorded as relative frequencies. Covariance and the Pearson linear correlation index were used for comparisons.

RESULTS

The study period included a total of 11,481 surgical sessions, of which 71% were minor surgery and the remainder were major outpatient surgery. A mean of 9.7 operations were performed in each session and the overall operating room occupancy was 71.9%. Four SOT descriptors (minor surgery, multiple minor skin lesions, nail surgery, and malignant tumors with primary closure) were sufficient to classify 86.7% of the operations performed. The operating room down-time was 0.15 SOT (9minutes) in 91.3% of operations. The mean SA1 index was 1.20. Overall surgical productivity measured using the SA2 index was 96.46%. The Pearson correlation showed a statistically significant relationship between the increase in the number of patients per surgical session, the reduction in operating room occupancy, and the increase in SA2 operating room productivity.

CONCLUSIONS

The application of SOT descriptors enables us to quantify the complexity of the operations included in the surgical waiting list and to obtain indicators for the evaluation of surgical activity, improving efficiency in surgical time management.

Analysis of operating room activities in the dermatology department at Hospital Universitario de Fuenlabrada (2005-2010)

OBJECTIVE

To analyze data corresponding to patients who underwent dermatological surgery in an operating room.

MATERIAL AND METHODS

This was a descriptive, retrospective study of operating room activities in the dermatology department of Hospital Universitario de Fuenlabrada in Madrid between January 2005 and December 2010. We analyzed the relative frequency of a range of patient and procedure-related variables, as well as substitution and cancellation rates, the proportional risk of complications, and operating room efficiency.

RESULTS

In the period analyzed, 11,516 patients underwent surgery: 9351 required minor surgery, 1998 major ambulatory surgery, and 167 surgery requiring hospitalization. Simple excision was the most common procedure (64.7%), and in the majority of cases (85%), the condition was benign. The mean number of patients treated per day was 9.7, and mean operating room efficiency was 71.9%.

CONCLUSIONS

Accurate record-keeping is essential for analyzing operating room activities and comparing results with those from other centers. The analysis of patterns over time shows the effect of changes made on different indicators. In our case, a decrease in operating room efficiency was seen with an increase in the number of patients per day undergoing surgery.

Soil seed bank recovery occurs more rapidly than expected in semi-arid Mediterranean gypsum vegetation

BACKGROUND AND AIMS

Seed banks are critical in arid ecosystems and ensure the persistence of species. Despite the importance of seed banks, knowledge about their formation and the extent to which a seed bank can recover after severe perturbation remains scarce. If undisturbed, soil seed banks reflect a long vegetation history; therefore, we would expect that new soil seed banks and those of undisturbed soils require long periods to become similar with respect to both density and composition. In contrast, if soil seed banks are only a short- to mid-term reservoir in which long-term accumulation constitutes only a tiny fraction, they will recover rapidly from the vegetation. To shed light on this question, we evaluated seed bank formation in a semi-arid gypsum community.

METHODS

Soils from 300 plots were replaced with sterilized soil in an undisturbed semi-arid Mediterranean community. Seasonal changes in seed bank density and composition were monitored for 3 years by comparing paired sterilized and control soil samples at each plot.

KEY RESULTS

Differences in seed bank density between sterilized and control soil disappeared after 18 months. The composition of sterilized seed banks was correlated with that of the control plots from the first sampling date, and both were highly correlated with vegetation. Nearly 24 % of the seed bank density could be attributed to secondary dispersal. Most seeds died before emergence (66·41-71·33 %), whereas the rest either emerged (14·08-15·48 %) or persisted in the soil (14·59-18·11 %).

CONCLUSIONS

Seed banks can recover very rapidly even under the limiting and stressful conditions of semi-arid environments. This recovery is based mainly on the seed rain at small scales together with secondary dispersal from intact seed banks in the vicinity. These results emphasize the relevance of processes occurring on short spatial scales in determining community structure.

Pre-pubertal Di(2-ethylhexyl) Phthalate (DEHP) Exposure of Young Boars Did Not Affect SpermIn vitroPenetration Capacity of Homologous Oocytes Post-puberty

Di(2-ethylhexyl) phthalate (DEHP), a plastic softener used in polyvinylchloride (PVC) products (e.g., plastic bags and medical equipment), has been reported to have toxic effects on animal reproduction and is considered an environmental hazard based, mostly, on rodent studies. However, the doses used in these studies are often considerably higher than that presumed in human exposure. In the present study we used young boars as model animals to assess the effects of pre-pubertal DEHP exposure on the ability of spermatozoa to penetrate homologous oocytes in vitro. Eight pairs of cross-bred male boar siblings were used. One brother in each pair became, at random, the test animal exposed to DEHP per os, three times a week, from 3 to 7 weeks of age while the other acted as the control, i.e., placebo-exposed. Semen was collected and frozen between 8 and 9 months of age and stored until spermatozoa were evaluated for their ability to in vitro penetrate in vitro-matured homologous oocytes post-thaw. Both the penetration rate and the number of spermatozoa per oocyte were considered within expected ranges for frozen boar semen of good quality. Penetration rate did not significantly differ (p > 0.05) between the groups with DEHP-exposed: 50%; control: 59%, which could be owing to a large variation between boars, and between replicates. The number of spermatozoa in the ooplasm was low and similar (p > 0.05) between the groups with DEHP-exposed: 1.5 and the control: 1.7. Under the conditions of the present experiment, pre-pubertal exposure to DEHP does not seem to cause a deleterious effect on the in vitro fertilizing ability of frozen spermatozoa post-puberty.

Improving the efficiency of insemination with sex-sorted spermatozoa

The sorting of X- and Y-chromosome-bearing spermatozoa by flow cytometry is nowadays one of the most apt assisted-reproduction technologies in livestock production. Potential economic and biological benefits, as well as those related to easier management of herds, have been reported arising out of the application of this technique, especially in cattle. Yet, the sex-sorting procedure induces damage to spermatozoa, affecting their function and fertilizing ability. Different species present varying degrees of susceptibility to damage from the sorting process and each has its own requirements for sex-sorted insemination procedures. Thus, several new protocols and strategies have been designed for the handling of sorted spermatozoa, with the main objective of optimizing their fertilizing ability and the consequent application of flow-cytometric sex-sorting technology. This article reviews current advances in this technology, pointing out the components to be improved before this technology may be widely applied in different domestic species.

Optimal characteristics of spermatozoa for semen technologies in pigs

Despite the great potential of sperm technologies such as sperm cryopreservation and sperm sex sorting for the improvement of different aspects of swine production, artificial insemination with fresh or stored semen is currently the only sperm technology used at a commercial scale in the pig industry. The lower reproductive performance associated with the use of these sperm technologies is the reason for such limited use. Since optimal characteristics are required for successful application of frozen-thawed and sex-sorted boar spermatozoa, the present paper summarises the value of the current available methods for their functional assessment as well as the effects of these technologies on boar sperm functionality. In addition, strategies developed to reduce sperm damage and improve the yields of both sperm technologies in swine production are also reviewed with particular attention to the contributions of the authors.

In vitro maturation of porcine oocytes with retinoids improves embryonic development

In the present study, the effects of retinoid metabolite administration during in vitro maturation (IVM) on oocyte maturation, parameters of in vitro fertilisation (IVF) and embryo development were examined. Varying concentrations of 9-cis retinoic acid (RA; 0, 5, 50 and 500 nm; Experiment 1) and all-trans retinol (ROH; 0, 125, 1250 and 12 500 nm; Experiment 2) were included in the maturation medium. Cumulus-oocyte complexes were matured in vitro and inseminated with frozen-thawed spermatozoa. Presumptive zygotes were cultured for 16 h to assess IVF parameters or for 7 days to assess embryo development and quality. In Experiment 1, the oocyte maturation rate to metaphase II was significantly decreased (P < 0.001), with values below 5%, in the presence of the highest concentration of RA (500 nm). However, 5 and 50 nm RA had no effect compared with control. Treatment with 5 nm RA improved the blastocyst development rate (P < 0.001). In Experiment 2, the oocyte maturation rate did not differ between 125 and 1250 nm ROH treatment groups and control. However, treatment with 12 500 nm ROH was deleterious because no matured oocytes were observed following the treatment. The penetration rate was lower in the group treated with 1250 nm ROH compared with the 125 nm ROH-treated and control groups, but the blastocyst formation rate did not differ among the three groups. In conclusion, 5 nm RA in the IVM medium significantly increased the blastocyst formation rate, suggesting that RA may play an important role during IVM.

PSP-I/PSP-II spermadhesin exert a decapacitation effect on highly extended boar spermatozoa

PSP-I/PSP-II heterodimer is a major protein of boar seminal plasma that is able to preserve, in vitro, the viability, motility and mitochondrial activity of highly-extended boar spermatozoa. However, a relationship between the protective effects of the heterodimer and sperm capacitation is still unclear. The present study investigated the effect of the PSP-I/PSP-II (1.5 mg/mL) on membrane stability, intracellular calcium concentration ([Ca(2+)](I)) and plasma membrane and acrosome integrity of highly extended boar spermatozoa. Boar spermatozoa were diluted to 1 x 10(6) spermatozoa/mL and incubated at 38 degrees C in Phosphate-buffered saline (PBS) for 10, 30, 60, 120 and 300 min or in modified Tris-buffered medium (mTBM) for 10, 20, 30, 60 and 120 min. After each incubation time, the membrane stability (using Merocyanine-540/Yo-Pro-1), elevation of [Ca(2+)](I) (using Fluo-3-AM/PI) and the sperm plasma membrane and acrosome integrity (using SYBR-14/PI/PE-PNA) were evaluated by flow cytometry. As expected, exposure of the spermatozoa to the PSP-I/PSP-II preserved the plasma membrane and acrosome integrity compared to non-exposed spermatozoa in both media PBS and mTBM (p < .01). The evaluation of membrane stability showed no differences in the percentages of viable sperm with instable plasma membrane in the presence of the PSP-I/PSP-II compared to controls irrespective of the dilution media. The evaluation of the [Ca(2+)](I) levels showed that while spermatozoa incubated in mTBM and exposed to PSP-I/PSP-II had lower [Ca(2+)](I) than controls (39.08% vs. 47.97%, respectively; p < .05), no differences were observed in those samples incubated in PBS. However, a temporal evaluation of the samples showed that a similar proportion of live spermatozoa were able to achieve high levels of [Ca(2+)](I) and membrane instability independent of the presence of PSP-I/PSP-II. In conclusion, PSP-I/PSP-II exert a non-permanent decapacitation effect on highly extended boar spermatozoa that is related with a delay in the increase of [Ca(2+)](I) levels.

Immunohistochemical increase in cyclooxygenase-2 without apoptosis in different brain areas of subchronic nicotine- and D-amphetamine-treated rats

Cyclooxygenase-2 (COX-2) upregulation has been related to both neurodegeneration and physiological processes. To clarify whether nicotine-induced upregulation of COX-2 occurs, and to analyse its significance, a comparative immunohistochemical and Western blot study was performed on the frontoparietal cortex, hippocampus and cerebellar cortex of rats treated (14 days) with nicotine, D(+)amphetamine (0.35 and 1.16 mg free base/kg/day, respectively), or both drugs simultaneously. None of these treatments promoted neuronal apoptosis. Lipid peroxidation increased in the hippocampus of the nicotine-treated rats and in all the brain regions examined in the D(+)amphetamine rats, but not in the double-treated animals. Both molecules increased the COX-2 content (as determined by the number of immunopositive neurons and the intensity of their immunodeposits) in an area-, layer- and neuron type-dependent manner, in all brain regions in which a large number of COX-2 immunopositive neurons were observed in controls (the somatosensory cortical areas, CA-1, CA-3, the gyrus dentatus, the ectorhinal/perirhinal areas, and the gyrus cingularis). No increase was seen in the motor cortical areas, while a reduction was recorded in the cerebellar cortex; these regions had only a few immunopositive neurons in controls. Western blot analysis revealed a 50-80% increase in COX-2 in the brain cortex and hippocampus of nicotine-treated rats, and similar increases (150-200%) in the cortex of the D(+)amphetamine- and nicotine + D(+)amphetamine-treated rats. Nicotine-induced upregulation of COX-2 seems to be related to neuronal plasticity rather than neurodegeneration. Nicotine agonists might be useful in the treatment of cognitive disorders.

70 EFFECT OF CRYOPROTECTANT CONCENTRATION ON THE IN VITRO SURVIVAL AND CELL PROLIFERATION OF PORCINE BLASTOCYSTS VITRIFIED USING THE OPEN PULLED STRAW SYSTEM

The objective of the present project was to study the effect of the concentrations of ethylene glycol (EG) and dimethyl sulfoxide (DMSO) during vitrification on the survival and hatching rates of porcine blastocysts. Embryos were collected by laparotomy from weaned crossbred sows (n = 18), vitrified, and warmed (one-step dilution) as described by Cuello et al. (2004 Theriogenology 62, 1144–1152). Vitrification was performed in different concentrations of EG and DMSO (15%, 16%, and 17% v/v for each cryoprotectant) or in an EG-based medium (40% v/v) using superfine open pulled straws. Fresh and vitrified blastocysts were cultured for 24 h in TCM199 and assessed by stereomicroscopy during the culture. Blastocysts that reformed their blastocoelic cavities after warming, displaying a normal zona pellucida and excellent appearance, were considered viable. The in vitro survival rate was defined as the ratio of viable embryos divided by the total number of embryos cultured. The hatching rate is determined as the ratio of the number of embryos hatched in vitro to the total number embryos cultured. Some vitrified and fresh embryos classified as viable were processed for Hoechst 33342 staining and proliferation cell nuclear antigen (PCNA) inmunolocalization. The proliferation index was defined as the number of PCNA-positive nuclei divided by the total number of nuclei stained with Hoechst 33342. Data were analyzed by ANOVA using the MIXED procedure (SPSS version 11.5; SPSS, Inc., Chicago, IL, USA). Data were expressed as mean values � SEM. The survival rate was similar for fresh and vitrified blastocysts, except for blastocysts vitrified using 15% cryoprotectants, which displayed a lower (P < 0.05) survival rate (84.2 � 4.8%) than fresh blastocysts (94.6 � 5%) and blastocysts vitrified using 40% EG, 16%, or 17% EG-DMSO (88.8 � 4.9, 96.8 � 4.9, and 96.4 � 5%, respectively). Fresh blastocysts showed a higher (P < 0.05) hatching rate (80.7 � 4.5%) than their vitrified counterparts (range: 48.4 � 7.7–55.3 � 7.8%). Vitrified and fresh blastocysts showed similar cell proliferation indexes (range: 75.8 � 3.2–83.7 � 3). When only hatched blastocysts among groups were compared, the proliferation rate decreased (P < 0.05) after vitrification with 17% EG-DMSO. Among vitrification groups, there was no significant difference in the number of total cells. However, vitrified blastocysts had a lower (P < 0.05) total cell number (range: 116.6 � 6.7–124.8 � 6.6) than fresh blastocysts (195.5 � 11.4). In conclusion, under our experimental conditions, the concentration of EG-DMSO can be decreased until 16% in the vitrification medium with no reduction of the in vitro developmental ability of the blastocysts. In addition, a 40% EG-based medium can be used for vitrification with results similar to those achieved using a medium containing 16% EG-DMSO.

Factors affecting the success rate of porcine embryo vitrification by the Open Pulled Straw method

The objectives of this study were: (1) to evaluate the influence of porcine embryo developmental stage on in vitro embryo development after vitrification, (2) to study the efficiency of the one-step dilution procedure, compared with conventional warming, for vitrified embryos at different stages of development, and (3) to determine the influence of the embryo donor on the in vitro survival of vitrified embryos at morulae and blastocyst stages. Two to four cell embryos, morulae and blastocysts were collected by laparotomy from weaned crossbred sows (n=55). Vitrification and conventional warming were performed using the OPS procedure with Superfine Open Pulled Straws (SOPS). For one-step dilution, embryos were placed in 800 microl TCM199-HEPES containing 20% of new born calf serum and 0.13 M sucrose for 5 min. To evaluate development, two to four cell embryos, morulae and blastocysts were cultured in vitro for 120, 48 and 24h, respectively. Some fresh embryos from each developmental stage were not vitrified and cultured as controls. Embryos were morphologically evaluated for their developmental capacity during the in vitro culture by stereomicroscopy. The total cell number of embryos was assessed by Hoechst-33342 staining and fluorescence microscope observation. There was a significant effect of the stage of development on the in vitro survival, perihatching rate and the number of cells of embryos after vitrification and warming (Experiment 1; p<0.001). The survival and perihatching rates of two to four cell embryos were lower than those obtained for morulae and blastocysts (p<0.001). No differences (p>0.05) in survival rates were found between vitrified and fresh blastocysts. The warming procedure did not affect the development and total cell number of vitrified two to four cell embryos, morulae or blastocysts (Experiment 2). However, donor had a significant effect (p<0.001) on the in vitro development and the number of cells of morulae and blastocysts after vitrification and warming (Experiment 3). In conclusion, the embryo developmental stage and the embryo donor were important factors that affected the development of porcine embryos after OPS-vitrification and warming. OPS-vitrification and the one-step dilution are efficient procedures to be used with intact porcine morulae and blastocysts.

Improving the fertilizing ability of sex sorted boar spermatozoa

The sex sorting of spermatozoa by flow cytometry induces damage, since sperm cells are highly diluted, affecting their functionality and fertilizing ability. In this work it was investigated whether the concentration of sex sorted spermatozoa by the sedimentation method, rather than centrifugation, in combination with the presence of the seminal plasma protein PSP-I/PSP-II heterodimer may improve their fertilizing ability. Spermatozoa were sorted by flow cytometry and collected in BTS with 10% of seminal plasma (group C: control) or with 1.5mg/mL of PSP-I/PSP-II heterodimer (group H). Collected spermatozoa from each medium were split into two aliquots. One aliquot of each group was centrifuged (800 x g/5 min) just after sorting and stored 16-18 h at 17 degrees C (groups Cc and Hc) at 6 x 10(6)sperm/mL. The second aliquot was directly stored at 17 degrees C for 16-18 degrees C (group Cs and Hs). After storage the supernatant was discarded and the sedimented pellet adjusted to 6 x 10(6)sperm/mL. Membrane integrity, acrosome status and motility characteristics of spermatozoa from all groups were assessed. Post-weaning pre-ovulatory sows were inseminated by laparoscopy into the oviduct with 0.3 x 10(6) sex sorted spermatozoa to assess their ability to penetrate oocytes in vivo. Putative zygotes were collected 18 h after insemination by washing the oviduct. Penetration and monospermic rates were evaluated. After 16-18 h of storage, centrifuged spermatozoa collected with 10% seminal plasma or 1.5 mg/mL PSP-I/PSP-II heterodimer after sex sorting showed lower (p<0.05) percentages of membrane integrity, motility and fertilization than sedimented spermatozoa. Overall, the presence of 10% seminal plasma or PSP-I/PSP-II heterodimer did not affect the results. However, a positive effect of PSP-I/PSP-II heterodimer (p<0.05) was observed in sedimented spermatozoa. Hence, our results indicate that the sedimentation method in the presence of PSP-I/PSP-II heterodimer improves the in vivo fertilizing ability of sex sorted boar spermatozoa.

Vitrification of in vitro cultured porcine two-to-four cell embryos

The objective of this experiment was to evaluate the effect of a 5-day period of in vitro culture of two-to-four cell porcine embryos up to the blastocyst stage on their ability to survive vitrification and warming. In order to increase the cooling rate, superfine open pulled straws and Vit-Master((R)) technology were used for vitrification. Two-to-four cell embryos were collected from weaned sows (n=11) on day 2 (D0=onset of estrus). Some embryos (N=63) were vitrified within 3h after collection, warmed and cultured for 120h (Group V2). Additionally, 81 two-to-four cell embryos were cultured for 96h in order to obtain blastocysts; these were then vitrified, warmed and cultured for 24h (Group VB; N=65). The remaining two-to-four cell embryos were used as controls and thus not vitrified (control embryos; N=70) but were cultured in vitro for 120h. The V2, VB and control embryos were evaluated for their developmental progression and morphology during culture. All embryos (V2, VB and controls) were fixed on the same day of development in order to assess the total number of blastomeres. The survival and blastocyst formation rates obtained from V2 embryos were very poor (9.6+/-0.7% and 3.2+/-0.5%, respectively). The survival and hatching rates of VB embryos (75.0+/-0.69% and 33.6+/-0.13%) were lower (p<0.001) than those obtained with control embryos (89.1+/-0.8% and 47.5+/-0.12%). Hatched VB embryos had a lower (p<0.01) total cell number than hatched control embryos (70.3+/-4.5 versus 90.6+/-3.2, respectively). There was no difference between expanded VB and control blastocysts. In conclusion, blastocysts derived from in vitro culture of two-to-four cell pig embryos could be successfully vitrified using SOPS straws and Vit-Master.

Retained Functional Integrity of Bull Spermatozoa after Double Freezing and Thawing Using PureSperm® Density Gradient Centrifugation

The main aim of this study was to compare the motility and functional integrity of bull spermatozoa after single and double freezing and thawing. The viability and morphological integrity of spermatozoa selected by PureSperm density gradient centrifugation after cryopreservation of bovine semen in two commercial extenders (Experiment 1) and the function of bull spermatozoa before and after a second freezing and thawing assisted by PureSperm selection (Experiment 2) were examined. On average, 35.8 +/- 12.1% of sperm loaded onto the PureSperm density gradient were recovered after centrifugation. In Experiment 1, post-thaw motility and acrosome integrity were higher for spermatozoa frozen in Tris-egg yolk extender than in AndroMed, whether the assessments were made immediately after thawing [80.4 +/- 12.7 vs 47.6 +/- 19.0% motile and 78.8 +/- 8.3 vs 50.1 +/- 19.5% normal apical ridge (NAR), p < 0.05] or after preparation on the gradient (83.3 +/- 8.6 vs 69.4 +/- 15.9% motile and 89.5 +/- 7.2 vs 69.1 +/- 11.4% NAR, p < 0.05). For semen frozen in Tris-egg yolk extender, selection on the PureSperm gradient did not influence total motility but significantly improved the proportion of acrosome-intact spermatozoa. After the gradient, both the total motility and percentage of normal acrosomes increased for spermatozoa frozen in AndroMed (Minitüb Tiefenbach, Germany). In Experiment 2, there was no difference in sperm motility after the first and second freeze-thawing (82.9 +/- 12.7 vs 68.8 +/- 18.7%). However, the proportion of acrosome-intact spermatozoa was significantly improved by selection through the PureSperm gradient, whether measured by phase contrast microscopy (78.9 +/- 9.7 vs 90.4 +/- 4.0% NAR, p < 0.05) or flow cytometry (53.4 +/- 11.7 vs 76.3 +/- 6.0% viable acrosome-intact spermatozoa, p < 0.001). The improvement in the percentage of spermatozoa with normal acrosomes was maintained after resuspension in the cooling extender and cooling to 4 degrees C (88.2 +/- 6.2) and after re-freezing and thawing (83.6 +/- 6.56% NAR). However, flow cytometric assessment of the sperm membranes revealed a decline in the percentage of viable spermatozoa with intact membranes after the second freezing and thawing compared with after gradient centrifugation (76.3 +/- 6.0% vs 46.6 +/- 6.6%, p < 0.001) to levels equivalent to those obtained after the first round of freeze-thawing (53.4 +/- 11.7% viable acrosome-intact spermatozoa). Sperm movement characteristics assessed by computer-assisted analysis were unaffected in the population selected on the PureSperm gradients but declined after cooling of the selected and extended spermatozoa to 4 degrees C. There was no further change in these kinematic measurements after the cooled spermatozoa had undergone the second round of freeze-thawing. These results demonstrate that bull semen can be frozen and thawed, followed by a second freeze-thawing cycle of a population of spermatozoa selected by PureSperm, with retained motility and functional integrity. This points to the possibility of using double frozen spermatozoa in bovine artificial insemination programmes and to the potential benefits of PureSperm density gradient centrifugation for the application of cryopreserved bull spermatozoa to other biotechnological procedures such as flow cytometric sex sorting followed by re-freezing and thawing.

Effect of storage in short- and long-term commercial semen extenders on the motility, plasma membrane and chromatin integrity of boar spermatozoa

For artificial insemination (AI) in pigs, preservation of liquid boar semen at 16-20 degrees C is still common practice as sperm cryopreservation remains suboptimal in this species. To meet the different needs of the swine industry, several extenders have been developed to preserve semen in liquid form for short--and long-term storage. In the present study, three different commercial extenders devised for short-term (BTS+) or long-term preservation (MR-A and X-Cell), were used to test whether storage of semen from four mature, fertile boars at 17 degrees C for 96 h would affect sperm characteristics relevant for fertility, such as motility, membrane integrity and chromatin stability. Computer-assisted sperm analysis, and stainings with the acylated membrane dye SYBR-14/propidium iodide, and acridine orange in connection with flow cytometry were used to evaluate these variables. Percentages of total motile spermatozoa decreased slightly, but significantly, after 72-96 h. While membrane integrity values varied during the period of study, no significant changes in either membrane integrity or chromatin stability were, however, registered. This suggests a customary 96-day storage at 17 degrees C in these extenders was too short an interval to cause losses of integrity in nuclear DNA in the boar population studied.

Immunolocalization and possible functional role of PSP-I/PSP-II heterodimer in highly extended boar spermatozoa

PSP-I/PSP-II heterodimer is a major protein of boar seminal plasma which is able to preserve, in vitro, the viability, motility, and mitochondrial activity of highly extended boar spermatozoa for at least 5 hours. However, little is known about the binding pattern of the heterodimer to the sperm plasma membrane and its eventual relation with the maintenance of the sperm functionality. The present study investigated the effect of exposing highly extended boar spermatozoa (1 million/mL) to 1.5 mg/mL of PSP-I/PSP-II for 0.5, 5, and 10 hours at 38 degrees C on sperm characteristics and the changes in PSP-I/PSP-II localization as a result of both the addition of PSP-I/PSP-II to the extender and the incubation time. Exposure of the spermatozoa to PSP-I/PSP-II preserved sperm viability, motility, and mitochondrial activity when compared to nonexposed spermatozoa. This protective effect lasted for 10 hours (P < .05). After immunolabeling of highly extended semen with rabbit monospecific polyclonal antibody against PSP-I/PSP-II, the percentage of immunopositive spermatozoa declines over time from 71% (0.5 hours) to 49% (10 hours). However, more than 80% of spermatozoa remained labeled during the 10-hour incubation period if PSP-I/PSP-II was added. Scanning electron microscopy revealed 4 different binding patterns. The heterodimer was mainly localized to the acrosomal area, being redistributed to the postacrosomal area or lost during in vitro incubation. In conclusion, the protective effect of the heterodimer appears to be related to its adhesion to the acrosomal area, and the loss of this protective effect coincides with a stepwise redistribution of PSP-I/PSP-II during incubation.

Dissecting the Protective Effect of the Seminal Plasma Spermadhesin PSP-I/PSP-II on Boar Sperm Functionality

To dissect the protective activity of PSP-I/PSP-II, the effect of the isolated subunits PSP-I and PSP-II and their affinity-purified tryptic peptide and glycan fractions on the viability, mitochondrial activity, and motility of highly diluted boar spermatozoa was investigated. High dilution exerted a negative effect on control spermatozoa. Incubation of spermatozoa with PSP-I/PSP-II or with its PSP-II subunit had a protective effect on sperm functionality, high mitochondrial membrane potential, and sperm motility. These effects were less pronounced when spermatozoa were incubated with the PSP-I subunit. It was noteworthy that motility was abolished by incubation of spermatozoa with isolated PSP-I. Trypsin-degraded PSP-I/PSP-II, PSP-I, and PSP-II reproduced the effects of the native proteins. Incubating spermatozoa with the glycan-depleted tryptic-peptide fraction of PSP-I/PSP-II for 5 hours preserved a higher percentage of viable spermatozoa than when sperm was incubated for the same time with the native heterodimer, trypsin-digested PSP-I/PSP-II, the glycan fraction or without added proteins. However, sperm motility decreased as the concentration of added peptide fraction increased. On the other hand, spermatozoa incubated with the glycan fraction showed lower values than spermatozoa incubated with the peptide fraction. We concluded that the subunits of the PSP-I/PSP-II heterodimeric spermadhesin exert different activities on sperm functions. The finding that the beneficial effect of the native PSP-I/PSP-II on the functionality of highly diluted boar spermatozoa is largely preserved in its isolated PSP-II subunit and does not appear to require the glycan moiety points to a peptide moiety as a potential sperm function-preserving additive of highly diluted boar spermatozoa.

349 IMPROVING THE FUNCTIONALITY OF STORED FLOW CYTOMETRICALLY SEX-SORTED BOAR SPERMATOZOA: SEDIMENTATION VS. CENTRIFUGATION

Centrifugation has been the routine procedure used to concentrate the highly diluted spermatozoa obtained after sorting. However, this harmful procedure has a detrimental effect on the lifespan of the spermatozoa, particularly when a short-term storage period is required to perform the inseminations in the farms. The aim of the study was to evaluate the procedure of concentration by sedimentation of the flow cytometrically sex-sorted boar spermatozoa after a 24-h storage period, in terms of sperm functionality and recovery efficiency. Spermatozoa were sex-sorted by flow cytometry (Johnson and Welch 1999 Theriogenology 52, 1323-1342) and collected in 50-mL tubes containing 5 mL of Beltsville thawing solution (BTS) with 10% seminal plasma (SP). The collected samples were split into two aliquots. The first aliquot was concentrated by centrifugation (800g/5 min) just after sorting and stored at 17�C for 24 h at a concentration of 6 � 106 sperm/mL. The second aliquot was directly stored (0.5 � 106 sperm/mL) at 17�C for 24 h. In this case, after storage the supernatant was discarded and the pellet obtained by sedimentation was adjusted to 6 � 106 sperm/mL. For assessment of the sperm functionality after the storage, motility and viability of the spermatozoa were analyzed using a CASA system (Sperm Class Analyzer; Microptic, Barcelona, Spain) and a EPICS XL flow cytometer (Coulter Corporation, Inc., Miami, FL, USA) after the sperm were stained with propidium iodide and SYBR-14, respectively. For assessment of the recovery efficiency, the total number of spermatozoa in each sample was counted. The results are expressed as percentages of five replicates. Statistical analysis was performed using a �2 test. Percentages of motile and viable spermatozoa just after sorting were 80% and 83.3%, respectively. After storage at 17�C for 24 h, the percentage of viable spermatozoa was significantly higher (P < 0.05) in settled spermatozoa (82.4%) compared to centrifuged spermatozoa (63.3%). Similarly, the percentage of motile spermatozoa was significantly higher (P < 0.05) in settled spermatozoa (78.3%) compared to centrifuged spermatozoa (58.3%), as was the percentage of progressive motility (63.6% vs. 35.5%, respectively; P < 0.05). Interestingly, the percentage of cell recovery was significantly higher (P < 0.05) after sedimentation (80% of the sorted population) than after centrifugation (60.3% of the sorted population). The results show that sedimentation is more beneficial than centrifugation when short-term storage of sex-sorted boar sperm is required. This work was supported by CDTI and Fundaci�n Seneca.

352 IMPROVING THE EFFICIENCY OF LAPAROSCOPIC INTRAOVIDUCTAL INSEMINATION WITH SEX-SORTED BOAR SPERMATOZOA

The insemination of a low number of sex-sorted spermatozoa is a critical issue that must be solved in order to enable the commercial application of this technology in pigs. A new procedure for laparoscopic intraoviductal insemination in sows has recently been reported (Vazquez et al. 2005 Reprod. Dom. Animals 40, 375 abst.). To improve the efficiency of this technique, this experiment was designed to determine the influence of insemination time, relative to the time of ovulation, on the number and quality of zygotes recovered after laparoscopic insemination of sows with sex-sorted spermatozoa. Spermatozoa were stained with Hoechst 33342 and sexed using the EPICS Altra flow sorter (Coulter Corporation, Miami, FL, USA) modified to operate at 42 psi for spermatozoa. Sorted spermatozoa were collected in tubes containing 1.5 mL of TEST-yolk (2%)-seminal plasma (10%). Post-weaning crossbred sows (n = 212; parity 2-4) were hormonally treated with eCG (Folligon; Intervet, Boxmeer, The Netherlands) and hCG (Veterin Corion, Divasa, Spain) and their ovaries were examined using transrectal ultrasonography at intervals of 4 h from 30 h after hCG injection to the laparoscopic insemination. Sows were allotted into three groups according to their ovarian status at insemination: preovulatory (P; n = 131), ovulating (O; n = 43), and ovulated (CL; n = 38) follicles. Follicle status was reconfirmed at insemination by direct observation using the laparoscope. Sows were inseminated in both oviducts with 0.3 million sex-sorted spermatozoa in 0.1 mL of extender. Eighteen hours later, putative zygotes were collected by washing the oviducts after laparotomy, fixed, stained with lacmoid, and examined by phase-contrast microscopy. Penetration rates were evaluated as numbers of monospermic and polyspermic oocytes per oocytes collected. Monospermic rates were evaluated as numbers of monospermic oocytes per oocytes penetrated. Data were analyzed by ANOVA. The number of putative zygotes collected were 2825, 957, and 736 for P, O, and CL groups, respectively. Penetration rates were not different (P > 0.05) among groups (90.4%, 94.5%, and 93.7% for P, O, and CL, respectively). However, the monospermic rate was significantly higher (P < 0.05) in the P group (97.4%) when compared to the O or CL groups (66.7% and 5.1% for O and CL, respectively). Moreover, percentages of sows with six or more zygotes, potentially able to carry the pregnancy to term, were 90.8% and 46.5% for P and O groups, respectively (P < 0.05). No sow of the CL group presented six or more zygotes. In conclusion, laparoscopic insemination should be performed only in sows with preovulatory follicles when sex sorted spermatozoa are inseminated using this technology. This work was supported by CDTI and Fundacion Seneca.