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1.
Theriogenology ; 82(6): 884-9, 2014 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-25108794

RESUMEN

High levels of reactive oxygen species (ROS), which may be related to reduced semen quality, are detected during semen cryopreservation in some species. The objectives of this study were to measure the oxidative stress during ram semen cryopreservation and to evaluate the effect of adding 2 antioxidant mimics of superoxide dismutase (Tempo and Tempol) during the cooling process on sperm motility, viability, acrosomal integrity, capacitation status, ROS levels, and lipid peroxidation in frozen and/or thawed ram spermatozoa. Measuring of ROS levels during the cooling process at 35, 25, 15, and 5 °C and after freezing and/or thawing showed a directly proportional increase (P < 0.05) when temperatures were lowering. Adding antioxidants at 10 °C confered a higher motility and sperm viability after cryopreservation in comparison with adding at 35 °C or at 35 °C/5 °C. After freezing and/or thawing, sperm motility was significantly higher (P < 0.05) in Tempo and Tempol 1 mM than that in control group. Percentage of capacitated spermatozoa was lower (P < 0.05) in Tempo and Tempol 1 mM in comparison with that in control group. In addition, ROS levels and lipid peroxidation in group Tempo 1 mM were lower (P < 0.05) than those in control group. These results demonstrate that ram spermatozoa are exposed to oxidative stress during the cooling process, specifically when maintained at 5 °C and that lipid peroxidation induced by high levels of ROS decreases sperm motility and induces premature sperm capacitation. In contrast, the addition of Tempo or Tempol at 0.5 to 1 mM during the cooling process (10 °C) protects ram spermatozoa from oxidative stress.


Asunto(s)
Crioprotectores/farmacología , Óxidos N-Cíclicos/farmacología , Estrés Oxidativo/efectos de los fármacos , Análisis de Semen/veterinaria , Preservación de Semen/veterinaria , Ovinos/fisiología , Espermatozoides/efectos de los fármacos , Animales , Criopreservación/veterinaria , Óxidos N-Cíclicos/administración & dosificación , Masculino , Espermatozoides/fisiología , Marcadores de Spin
2.
Theriogenology ; 79(5): 842-6, 2013 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-23375779

RESUMEN

The main objective was to study the effects, on sperm function, of the addition of two superoxide dismutase (SOD) analogues (Tempo and Tempol) to alpaca semen extender for cryopreservation. Twelve alpaca semen samples were collected using an artificial vagina and then diluted at a 1:3 ratio in an extender based on skim milk, egg yolk, and fructose. Each semen sample was divided into three equal parts to form the following groups: control, Tempo (1 mM), and Tempol (1 mM). Groups were cooled to 5 °C in 90 minutes (-1 °C in 3 minutes); when samples reached approximately 10 °C, SOD analogues were added to the respective groups. At 5 °C, ethylene glycol (final concentration, 0.1 M) was added to each group. After 30 minutes at 5 °C, samples were loaded in 0.25 mL plastic straws, placed in liquid nitrogen vapor for 15 minutes, and then plunged. Percentages of sperm motility, functional sperm membrane integrity, and viable sperm with intact acrosomes were evaluated before and after freeze-thaw using visual analysis, the hypoosmotic swelling test, and the double-stain trypan blue/giemsa technique, respectively. The Terminal deoxymucleotidyl transferase dUTP Nick End Labeling assay was performed for evaluation of sperm DNA fragmentation of frozen-thawed sperm. Sperm motility was higher (P < 0.05) in the Tempol and Tempo groups than in the control group (mean, 22.1%, 19.7%, and 11.2%, respectively), with similar results for functional sperm membrane integrity. Additionally, DNA fragmentation was lower (P < 0.05) in the Tempol group (16.7%) than in the control group (38.8%). Viable sperm with intact acrosomes were not affected by the use of SOD analogues. There was a negative correlation (r = -0.58) between DNA fragmentation of alpaca sperm and sperm motility after freeze-thawing, but DNA damage was neither related to functional membrane integrity nor viable sperm with intact acrosomes. We concluded that DNA fragmentation and loss of motility during cryopreservation of alpaca sperm could be partially prevented by supplementation of the semen extender with 1 mM Tempo or Tempol.


Asunto(s)
Antioxidantes/farmacología , Camélidos del Nuevo Mundo , Criopreservación/veterinaria , Óxidos N-Cíclicos/farmacología , Preservación de Semen/veterinaria , Superóxido Dismutasa/farmacología , Acrosoma/efectos de los fármacos , Animales , Criopreservación/métodos , Fragmentación del ADN , Masculino , Semen/efectos de los fármacos , Preservación de Semen/métodos , Motilidad Espermática , Marcadores de Spin
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