Browsing by Author "Campoverde Guailacela, Byron Alexander"

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Efecto del resveratrol sobre la capacidad fecundante in vitro de espermatozoides bovinos congelados y vitrificados
(Universidad de Cuenca, 2023-10-27) Aguirre Narea, Brian Oswaldo; Campoverde Guailacela, Byron Alexander; Galarza Lucero, Diego Andrés
This research evaluated the effect of Resveratrol (RES) on the kinematics and in vitro fertilizing capacity of frozen and vitrified bovine spermatozoa. Four treatments were evaluated according to RES supplementation (0 [control] and 50 µM) and cryopreservation method (conventional freezing [CF] and vitrification [VIT]): CF-RES (n=80 straws); CF-Co (n=80 straws); VIT-RES (n=20 cryotubes), and VIT-Co (n=20 cryotubes). Each treatment was objectively evaluated for its kinematics and fertilizing capacity using a Computer Assisted Sperm Analysis system (CASA®) and in vitro fertilization (200 oocytes/treatment), respectively. Results showed better cryoresponse kinematics with freezing treatments (CFRES and CF-Co) than with vitrification treatments (VIT-RES and VIT-Co). The CF-RES treatment produced a higher (P<0.05) total motility (TM) and progressive motility (PM) than the CF-Co treatment, while the VIT-RES treatment produced a higher (P<0.05) beat cross frequency (BCF) than the VIT-Co treatment. The CC-RES treatment produced a higher (P<0.05) cleavage rate than the CF-Co and VIT- RES treatments (64.0±3.40% vs. 34.7±3.44% and 42.0±4.96%, respectively). Likewise, the CF-RES treatment produced a higher percentage of blastocysts (P<0.05) than all treatments (CF-RES=22.5±3.11% vs. CCCo=10.2±2.29%; VIT-RES=8.0±3.88%; and VIT-Co=4.0±2.8%). Furthermore, a correlation (P<0.05) was evidenced in the CC-RES treatment between motilities and lateral head displacement amplitude, and cleavage and blastocyst rates. In conclusion, RES improved the motility and in vitro fertility of spermatozoa after freezing, however, in vitrification it only improved one kinetic parameter.
Effect of resveratrol on cryopreservation of bull spermatozoa by conventional slow freezing or ultrarapid freezing
(Conference of the International Embryo Technology Society, 2024) Jaramillo López, Jennifer Alexandra; Campoverde Guailacela, Byron Alexander; Aguirre Narea, Brian Oswaldo; Amón Togra, Nicole Alexandra; Galarza Lucero, Diego Andrés; Samaniego Campoverde, Jorge Xavier
Resveratrol (RES) is a powerful antioxidant with free radical scavenger properties that result in a reduction in reactive oxygen species (ROS) generation and lipid peroxidation, these effects have been demonstrated in cryopreserved spermatozoa. This work evaluated the effect of RES (0 µM as control and 50 µM) on the cryopreservation of bull spermatozoa by conventional slow (CS) or ultrarapid (UR) freezing on post-thaw quality and fertility. Twenty-four ejaculates from four fertile bulls (six per bull) were collected using an artificial vagina and then diluted with TCG-EY (tris-citric acid-glucose + 6% egg yolk). Four treatments per ejaculation were conformed according to the freezing method and RES addition: CS-RES (n = 80), CS-0 (n = 80), UR-RES (n = 24), and UR-0 (n = 24). The CS freezing method was done by exposing the 0.25-mL sperm sample straws (plus 5% glycerol) to liquid nitrogen (NL) vapors, and the UR freezing was made using submerging 30-µL drops of samples (plus 100 mM sucrose) into NL. Initially, the kinetic parameters, plasma, and acrosome membranes integrity (IPIA), and oxidative stress were assessed using a CASA system (SCA®), PI/PNA-FICT double fluorescence test, and Cell ROX Deep Red test. After that, IVF based on cleavage and blastocyst rates from the four treatments spermatozoa were assessed using 200 in vitro-matured bovine oocytes in each treatment. Eight IVF sessions were performed using two cryopreserved semen per bull. Sperm samples from all treatments were selected by Percoll (45/90%) before IVF. A factorial ANOVA and Tukey test were used to assess the interactions between the “freezing method” and “RES dose.” The results showed significant (P < 0.05) differences between bulls regarding post-thaw sperm quality. The CS freezing treatments yielded a better sperm cryoresponse than UR freezing treatments, irrespective of RES addition. After CS-RES treatment, the total and progressive motilities, and IPIA percentages were higher (P < 0.05) than after CS-0, UR-RES, and UR-0 treatments. In addition, the UR-RES treatment produced greater (P < 0.05) values of the beat cross frequency and lower values (P < 0.05) of oxidative stress than the UR-0 treatment. The CS-RES treatment produced a higher (P < 0.05) cleavage rate (%) than the CS-0 and UR-RES treatments (64.0 ± 3.40 vs 34.7 ± 3.44 and 42.0 ± 4.96, respectively). Likewise, the CS-RES treatment produced a higher (P < 0.05) blastocyst rate (%) than all treatments (CS-RES: 22.5 ± 3.11 vs CS-0: 10.2 ± 2.29; UR-RES: 8.0 ± 3.88; and UR-0: 4.0 ± 2.8). In conclusion, RES improved the motility, plasmatic and acrosomal membrane integrity, and in vitro fertility of spermatozoa after the freezing-thawing process. However, after ultra-rapid freezing, RES reduced only oxidative stress.
Effect of resveratrol supplementation in conventional slow and ultra-rapid freezing media on the quality and fertility of bull sperm
(2024) Aguirre Narea, Brian Oswaldo; Amón Togra, Nicole Alexandra; Jaramillo López, Jennifer Alexandra; Galarza Lucero, Diego Andrés; Duma Pauta, José Mauricio; Samaniego Campoverde, Jorge Xavier; Taboada Pico, Juan Wualverto; Campoverde Guailacela, Byron Alexander
The study investigated the impact of resveratrol (RES) on bull sperm cryopreservation employing conventional slow (CS) and ultra-rapid (UR) freezing methods on sperm quality and in vitro fertility. Twenty-four ejaculates from four bulls were divided into four groups based on the cryopreservation method and RES addition: CS-RES (n = 80), CS-Co (n = 80), UR-RES (n = 24), and UR-Co (n = 24). The CS freezing involved exposing sperm straws with 5% glycerol to liquid nitrogen (LN2) vapors, while UR freezing submerged sperm drops with 100 mM sucrose directly into LN2. Overall, sperm kinematic parameters and integrity of plasma and acrosome membranes significantly decreased (P < 0.001) after cryopreservation. Post-thaw values of motilities (total [TM] and progressive [PSM]), velocities (curvilinear and straight-line), beat cross frequency (BCF), and sperm with intact plasma membrane/intact acrosome (PI-/PNA-) were higher (P < 0.05) with CS-RES and CS-Co treatments compared to UR-RES and UR-Co treatments. CS-RES treatment resulted in greater percentages (P < 0.05) of TM, PSM, PI-/PNA-, and fertility (blastocyst rate) than their control, CS-Co; while UR-RES showed higher BCF values (P < 0.05) than its control, UR-Co. Additionally, UR-RES treatment exhibited lower oxidative stress percentages than UR-Co (P < 0.05). This study presents the following conclusions: (1) the CS freezing resulted in better cryosurvival of bull sperm than UR freezing; (2) the RES supplementation to CS freezing medium improved sperm motility, membrane integrity, and fertility; and (3) despite low cryosurvival sperm and fertility, the RES addition to ultra-rapid freezing medium reduced oxidative stress.