| 1. |
- de Paz, Paulino, et al.
(author)
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The relationship between ram sperm head morphometry and fertility depends on the procedures of acquisition and analysis used.
- 2011
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In: Theriogenology. - : Elsevier. - 0093-691X .- 1879-3231. ; 76:7, s. 1313-1325
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Journal article (peer-reviewed)abstract
- Sperm head morphometry is a parameter in the evaluation of semen that has been associated with fertility in two ways: comparing morphometric measures between predefined groups of fertility; or analyzing morphometric data by multivariate techniques to identify cell populations. We analyzed the morphometry of ram sperm head by three procedures and checked its relationship with male fertility. A Computer-Aided Sperm Morphometric Assessment procedure (CASMA), an image analysis software (NIS-Elements) in combination with an optical microscope (MO-NIS) and this image analysis software in combination with a scanning electron microscope (SEM-NIS) were used. Eight morphometric parameters were assessed: length, width, area, perimeter, ellipticity, form factor, elongation and regularity. We observed significant differences between the morphometric data of sperm head obtained with three study procedures. The CASMA procedure shows the highest values for all parameters and the SEM-NIS procedure the lowest. The analysis of a semen sample, when only the mean of morphometric parameters is used to describe the cell population, is too limited to interpret their fertilizing capacity. It is essential to analyze the complex structure of the samples by defining subpopulations by multivariate methods. With few exceptions, the means of each morphometric parameter differ between the three subpopulations analyzed in each procedure. Only the subpopulations obtained with the MO-NIS procedure showed a significant correlation with male fertility. In short, it is necessary to establish an instrumental standard for the analysis of sperm morphometry to obtain reliable results and we believe that the MO-NIS system presents these basic requirements.
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| 2. |
- Martínez-Pastor, Felipe, et al.
(author)
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Probes and techniques for sperm evaluation by flow cytometry
- 2010
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In: Reproduction in domestic animals. - : Blackwell Verlag. - 0936-6768 .- 1439-0531. ; 45 Suppl 2, s. 67-78
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Journal article (peer-reviewed)abstract
- CONTENTS: Flow cytometry has become an important technique in sperm evaluation and is increasingly used both for routine assessment and for research in veterinary science. We have revised the literature, describing fluorescent probes that have been used for analysing spermatozoa by flow cytometry, regarding: viability, acrosomal status, capacitation, mitochondrial status, apoptotic markers, oxidative stress markers, DNA damage, sperm counting and sperm sizing. Details and problems of some techniques are reviewed, with special attention to the occurrence of non-sperm particles in the samples ('debris'). New and promising aspects of flow cytometry, such as sperm sorting using viability markers as selection criteria, are highlighted. The relationship between flow cytometry analyses and fertility and their future improvements are considered.
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| 3. |
- Mata-Campuzano, María, et al.
(author)
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Effect of several antioxidants on thawed ram spermatozoa submitted to 37°C up to four hours.
- 2012
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In: Reproduction in domestic animals. - : Blackwell Verlag. - 0936-6768 .- 1439-0531. ; 47:6, s. 907-914
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Journal article (peer-reviewed)abstract
- Thawed ram spermatozoa were incubated at 37°C in the presence of dehydroascorbic acid (DHA), TEMPOL (TPL), N-acetyl-cysteine (NAC) and rutin (RUT), at 0.1 and 1 mm, in order to test their effects on sperm physiology. Cryopreserved spermatozoa from four rams were thawed, pooled, washed and incubated in TALP-Hepes with 1 mm or 0.1 mm of each antioxidant, performing a replicate with induced oxidative stress (Fe(2+) /ascorbate). Motility (CASA), viability and mitochondrial membrane potential (flow cytometry) were analysed at 2 and 4 h. Lipoperoxidation (MDA production), intracellular reactive oxygen species (ROS) and DNA status (TUNEL) were analysed at 4 h. Antioxidants, except DHA 0.1 mm, decreased motility and kinematic parameters, but had little effect on viability or mitochondrial activity. Except 1 mm DHA, the antioxidants reduced ROS at 4 h. Moreover, NAC 1 mm, rutin and TEMPOL reduced ROS and DNA damage in the presence of oxidative stress. N-acetyl-cysteine, rutin 1 mm and TEMPOL reduced lipoperoxidation in the presence of oxidative stress. However, DHA did not affect lipoperoxidation. At 1 mm, DHA increased DNA damage in the absence of oxidative stress. Dehydroascorbic acid effects could arise from spermatozoa having a low capacity for reducing it to ascorbic acid, and it may be tested in the presence of other antioxidants or reducing power. Future research should focus in testing whether the inhibition of motility observed for NAC, rutin and TEMPOL is reversible. These antioxidants might be useful at lower temperatures (refrigerated storage or cryopreservation) when their protective effects could be advantageous.
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| 4. |
- Mata-Campuzano, María, et al.
(author)
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Post-thawing quality and incubation resilience of cryopreserved ram spermatozoa are affected by antioxidant supplementation and choice of extender.
- 2015
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In: Theriogenology. - : Elsevier. - 0093-691X .- 1879-3231. ; 83:4, s. 520-528
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Journal article (peer-reviewed)abstract
- The performance of cryopreserved semen in ovine artificial insemination still needs improvement. Some antioxidants have been tested, with variable success. We cryopreserved semen from Churra rams using TES-Tris-fructose with 4% glycerol and 10% egg yolk (EY) or 3.5% soybean lecithin (SL), with 1 mM of reduced glutathione (GSH), Trolox, crocin, or cysteamine. Samples were analyzed after thawing and incubation (6 hours, 38 °C) for motility (computer-assisted sperm analysis [CASA]), viability, acrosomal integrity, apoptosis, mitochondrial activity, chromatin status, and lipoperoxidation (malondialdehyde production). Interactions (antioxidant/extender/incubation) were significant for most variables. Extenders yielded similar results, although SL depressed mitochondrial activity and linearity (P < 0.001), it improved motility (P < 0.05), DNA fragmentation (P < 0.05), and acrosomal damage (P < 0.001). The control, GSH, and Trolox showed greater viability with SL (P < 0.01). Cysteamine depressed motility (0 hours: 51.6 ± 2.0% vs. 32.3 ± 4.3%; 6 hours: no motility vs. 32.5 ± 1.9%; P < 0.001), but improved viability when using EY (P = 0.004). Crocin increased acrosomal damage (P = 0.022) but improved linearity-related parameters after thawing (P = 0.014). Trolox considerably reduced malondialdehyde production in both extenders (8.6 ± 0.4 nmol per 10(8) cells vs. 14.2 ± 0.3 in EY and 20 ± 0.6 in SL; P < 0.001). Interestingly, thiol antioxidants (cysteamine and GSH) increased DNA fragmentation (percentage of DNA fragmentation index), whereas crocin reduced it (P < 0.05). Interactions between extender and antioxidant must be taken into account for improving sperm cryopreservation. Soybean lecithin seems to be a suitable replacement for EY, but its effect on mitochondria must be investigated. Trolox and crocin might be useful for ram semen freezing.
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| 5. |
- Mata-Campuzano, Maria, et al.
(author)
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Quality, oxidative markers and DNA damage (DNA) fragmentation of red deer thawed spermatozoa after incubation at 37 °C in presence of several antioxidants.
- 2012
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In: Theriogenology. - : Elsevier. - 0093-691X .- 1879-3231. ; 78:5, s. 1005-1019
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Journal article (peer-reviewed)abstract
- Antioxidants may be useful for supplementing sperm extenders. We have tested dehydroascorbic acid (DHA), TEMPOL, N-acetyl-cysteine (NAC) and rutin on epididymal spermatozoa from red deer, during incubation at 37 °C. Cryopreserved spermatozoa were thawed, washed and incubated with 1 mM or 0.1 mM of each antioxidant, including oxidative stress (Fe(2+)/ascorbate). Motility (CASA and clustering of subpopulations), viability, mitochondrial membrane potential, and acrosomal status were assessed at 2 and 4 h. Lipoperoxidation, intracellular reactive oxygen species (ROS) and DNA damage (DNA) status (TUNEL) were checked at 4 h. Oxidative stress increased ROS, lipoperoxidation and DNA damage. Overall, antioxidants negatively affected motility and physiological parameters. Only DHA 1 mm protected motility, increasing the fast and progressive subpopulation. However, it had a detrimental effect on acrosomal and DNA status, in absence of oxidative stress. Tempol and rutin efficiently reduced lipoperoxidation, ROS, and DNA damage in presence of oxidative stress. NAC was not as efficient as TEMPOL or rutin reducing lipoperoxidation or protecting DNA, and did not reduce ROS, but its negative effects were lower than the other antioxidants when used at 1 mm, increasing the subpopulation of hyperactivated-like spermatozoa at 2 h. Our results show that these antioxidants have mixed effects when spermatozoa are incubated at physiological temperatures. DHA may not be suitable because of prooxidant effects, but TEMPOL, NAC and rutin may be considered for cryopreservation trials. In general, exposure of red deer spermatozoa to these antioxidants should be limited to low temperatures, when only protective effects may develop.
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| 6. |
- Mata-Campuzano, María, et al.
(author)
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Refrigerated storage of ram sperm in presence of Trolox and GSH antioxidants : effect of temperature, extender and storage time
- 2014
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In: Animal Reproduction Science. - : Elsevier BV. - 0378-4320 .- 1873-2232. ; 151:3-4, s. 137-147
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Journal article (peer-reviewed)abstract
- Antioxidants have a potential to improve the quality and fertility of refrigerated-stored ram semen. Reduced glutathione (GSH) and Trolox (0.2, 1 and 5mM) were evaluated in ram semen preserved at 15 and 5°C up to 48 and 96h, respectively. Extenders were also evaluated (15°C: Tris-citrate-fructose, TCF, without lipids, and TES-Tris-fructose 10% egg yolk, TTF-EY; 5°C: TTF-EY and 3.5% soybean lecithin, TTF-SL; INRA96 at both temperatures). Storage at 5°C resulted in poorer quality than 15°C up to 48h, while allowing acceptable quality at 96h. Antioxidants had few effects on sperm quality, with use of Trolox resulting in reduced motility and viability in TCF. Storage at 15°C in the TCF extender resulted in decreased motility, viability and mitochondrial activity compared with use of TTF-EY. Sperm quality when storage was at 5°C was similar, but storage in TTF-SL resulted in decreased motility and mitochondrial activity. Acrosomal status was only slightly affected by extender and antioxidant. Mitochondrial activity was improved by antioxidants in TTF-SL, and GSH at 5mM when semen was stored at 5°C in TTF-EY. A preliminary artificial insemination trial indicated that supplementation with GSH has the potential for improving lambing (P<0.1). In conclusion, use of antioxidants resulted in lesser effects than extender composition or storage time on quality of ram semen. Use of Trolox negatively impacted sperm quality and GSH had some positive impacts. The use of soybean lecithin requires further research to assess its impact on mitochondria.
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| 7. |
- Tamayo-Canul, Julio, et al.
(author)
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Effect of storage method and extender osmolality in the quality of cryopreserved epididymal ram spermatozoa.
- 2011
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In: Animal Reproduction Science. - : Elsevier. - 0378-4320 .- 1873-2232. ; 129:3-4, s. 188-199
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Journal article (peer-reviewed)abstract
- Post-mortem sperm recovery and cryopreservation could be a complement to germplasm banking in sheep, especially for endangered breeds. This study is an attempt to identify factors for improving the success of cryopreserving ram epididymal spermatozoa, considering the decrease of sperm quality with post-mortem time. Epididymal spermatozoa from 9 rams were kept at 5°C using three storage methods: within the epididymes, undiluted sperm mass, and diluted in extenders of different osmolality (TES-Tris-fructose at 320, 370 or 420 mOsm/kg, 20% egg yolk, 8% glycerol). At 0, 24, 48 and 72h, spermatozoa were cryopreserved using each extender. Samples were analyzed before and after cryopreservation by CASA (motility) and flow cytometry (viability and acrosomal status). Post-mortem time decreased pre-freezing and post-thawing sperm quality. Some storage x extender combinations improved the effect of post-mortem time on sperm quality. Both epididymis storage combined with the 420 extender, and storing the spermatozoa diluted in the 320 extender improved post-thawing quality, especially at long post-mortem times. Storing the spermatozoa diluted in the 370 extender was detrimental for the acrosomal status. These findings have practical applications. The simplest storage method (within the epididymes) seems to be adequate if hyperosmotic extenders were used for freezing. An alternative method could be storing the spermatozoa diluted in a hypoosmotic extender. These recommendations are limited to the osmolalities tested in this study (420 mOsm/kg and 320 mOsm/kg); other osmolalities should be tested.
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