Browsing by Author "Landi Loja, Blanca Gabriela"

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    Cryopreservation of dog epididymal spermatozoa by conventional freezing or ultra-rapid freezing with nonpermeable cryoprotectant
    (2021) Landi Loja, Blanca Gabriela; Santiago Moreno, Julián; Mejia Jara, Edisson Leonardo; Galarza Lucero, Diego Andrés; Castaño, Cristina; Sánchez Calabuig, María Jesús; Taboada Pico, Juan Wualverto; Soria Parra, Manuel Elías; Méndez Álvarez, María Silvana; Samaniego Campoverde, Jorge Xavier
    This study was aimed to assess the effectiveness of two methods for cryopreservation of dog epididymal spermatozoa, one by conventional freezing (CF) with shortening both equilibration and cooling times, and the other by ultra-rapid freezing (URF) with nonpermeable cryoprotectant. Sixty epididymides were recovered from thirty orchiectomized adult dogs and the sperm samples were retrieved by retrograde flushing using TCG-EY (tris, citric acid, glucose + 20% egg yolk) extender and then 20 pools were conformed. Each pool was divided into 2 aliquots and then cryopreserved by CF and URF methods respectively. The CF method maintained the cooled-pool samples for 2h (1h without and 1h with 5% glycerol) and then were frozen by liquid nitrogen (LN2) vapors for 2 min. The URF method cryopreserved the cooled-pool samples using TCG-EY+250 mM sucrose, equilibrating during 30 min (5 ◦C) and submerging 30-μL drops directly in LN2. The results showed that the URF method produced a lower percentage of total and progressive motilities and acrosome integrity (P < 0.05) than the CF method. However, the kinetic variables (curvilinear and straight-line velocities, straightness, linearity, wobble, amplitude of lateral head displacement, and beat-cross frequency) and plasma membrane integrity did not differ (P > 0.05) between both cryopreservation methods. Unlike the URF method, the width, area and perimeter of sperm head were reduced after the CF method (P < 0.05). In conclusion, despite the low motility achieved after the ultra-rapid freezing method, the similar values of kinetic, viability and head morphometric dimensions to those obtained after conventional freezing, suggest that ultra-rapid freezing with sucrose may be a useful alternative for the cryopreservation of canine epididymal sperm.
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    Evaluación de dos protocolos de congelación de espermatozoides epididimarios en la especie Canis Lupus familiaris
    (Universidad de Cuenca, 2021-09-17) Landi Loja, Blanca Gabriela; Mejía Jara, Edisson Leonardo; Galarza Lucero, Diego Andrés
    This study was aimed to assess two canine epididymal sperm freezing protocols on cryosurvival, one conventional (CF) that uses static liquid nitrogen (LN2) vapors, and another ultra-rapid (UF) that directly plunges drops (30uL) of sperm in LN2. For this purpose, sixty epididymides from 30 orchiectomized adult dogs were used. The sperm samples were retrieved by retrograde flushing and then thirty pools were conformed (3 epididymal samples/pool). Each pool was divided into 2 aliquots that were cryopreserved with both CF and UF protocols using either 5% glycerol and 250 mM sucrose, respectively, added to the TCG-EY extender (tris, citric acid, glucose plus 20% egg yolk). The results showed that the UF protocol produced lower motility (total and progressive) and acrosomal membrane integrity (P < 0.05) than the CF protocol. However, the kinetic variables (curvilinear and rectilinear velocities, straightness, linearity, oscillation, the amplitude of lateral head displacement and beat-cross frequency) and plasma membrane integrity (viability) did not differ (P > 0.05) between both cryopreserving protocols. Efficiently, the UF protocol did not vary (P > 0.05) the length, width, area, and perimeter of the sperm head with respect to the non-frozen values. In conclusion, the UF protocol affects motility compared to the CF protocol. Despite this, the achievement of kinetics and viability levels in conjunction with the invariance of the morphometric head dimensions opens up good expectations for its use in the efficient cryopreservation of epididymal sperm from domestic and non-domestic canines.