The aim of this study was to evaluate the effects of different concentrations of (+)-catechin or (-)-epigallocatechin gallate (EGCG) on goat semen freezability. Poolsof semen were processed (Experiment 1: 0, 15, 25, 50, 75, or 100µM (+)-catechin; Experiment 2: 0, 15, 25, 50, 75, or 100µM EGCG) and frozen. After thawing, the samples were evaluated for kinematics, plasma membrane (PMi) and acrosome integrity, morphology, and oxidative stress, at 0 and 1h. In Experiment 1, at 0h, VSL and VAP were greater (P<0.05) with 15µM than with 50 and 100; WOB was lower (P<0.05) with 100µM than with 0, 15, and 25; and BCF was higher (P<0.05) with 75 and 100µM than with 0. In turn, in Experiment 2, progressive motility was higher (P<0.05) with0 and 15µM than with50 and 75; LIN was lower (P<0.05) with75 and100µM than with0 and 15; WOB was higher (P<0.05) with0 and 15µM; and PMi was greater (P<0.05) with100µM than 0. Thus, (+)-catechin or EGCG at higher concentrations inhibits the kinematics of frozen goat sperm, in a transitory way, and 100µM of EGCG preserves the PMi.
The aim of this study was to evaluate the effect of green tea extract (GTE) on the spermatic parameters of Wistar rats, submitted or not to testicular heat shock (HS). For this, 48 animals were treated according to the experimental groups (G1: not exposed to HS and untreated; G2: exposed to HS and untreated; G3: not exposed to HS and treated with GTE; G4: exposed to HS and treated with GTE). Subgroups of rats were euthanized on days 15, 30, and 60 to recover the spermatozoa. The total motility (TM), vigor, spermatic morphology and concentration, mitochondrial membrane potential, plasma membrane integrity, and acrosome integrity (ACi) were analyzed. The TM was higher in G1 and G3 than in G2 and G4 on day 30, and higher in G4 on day 60. The overall means of TM and vigor were higher in G1 and G3 than in G2 and G4, as well as TM on day 60. For the morphology, G2 and G4 were lower than G1 and G3 on day 15, and G4 was lower than G1 and G3 on day 30. Moreover, in G1 and G3 morphology was higher on days 15 and 30, and in G4 it was lower on day 30, with the overall means being higher in G1 and G3 than in G2 and G4, as well as on days 15 and 60 compared to day 30. The overall mean of ACi, on day 30, was lower than on days 15 and 60 for all the groups. Therefore, HS is shown to be widely deleterious to the gametes, and the daily administration of 100 mg/kg green tea extract does not improve the spermatic parameters of Wistar rats, submitted or not to testicular HS, although it leads to better recovery of spermatic motility and morphology at 60 days.
The objectives of this study were to evaluate goat sperm sorting in continuous Percoll® density gradients and gamete freezability, in the presence or absence of phenolic antioxidants. For this, semen pools were sorted, frozen, and evaluated. The non-selected group (NSg) presented lower progressive motility (PM), linearity (LIN), straightness (STR), and wobble (WOB) than the selected groups, and straight line velocity (VSL) compared to those with catechin or resveratrol. The amplitude of lateral head displacement (ALH) was higher in NSg, and quercetin reduced the mitochondrial membrane potential (MMP). After thawing, the NSg presented lower PM than the selected groups, VSL and VAP (average path velocity) than the selected group with or without catechin, LIN and WOB than the selected with or without catechin or resveratrol, and STR than the selected with catechin. Moreover, NSg presented higher ALH and BCF than the samples selected with or without catechin. Plasma membrane integrity and intact and living cells were higher in the selected groups, and MMP was lower in the NSg and the selected group with quercetin. Thus, centrifugation in Percoll® continuous density gradients is a viable methodology to select goat sperm compatible with the freezing, especially in the presence of catechin or resveratrol.
Objective: This study evaluated the effects of green tea extract (GTE) on the recovery of testicular parenchyma of adult Wistar rats submitted to heat stress (HS). Methodology: Animals (n=84) were distributed and treated, according to the experimental group (G1: unstressed and untreated; G2: stressed and untreated; G3: unstressed and treated; G4: stressed and treated). Results: The overall mean of testicular weight, epithelial height and tubular diameter were lower (P<0.05) in G2 and G4, and day 60 presented a higher value (P<0.05) to the two first parameters. The gonadosomatic index and the volumes of the seminiferous epithelium were lower (P<0.05) in G2 and G4. The overall means of proper tunica volume was lower (P<0.05) on day 30. The seminiferous tubule on days 15 and 30 presented lower values (P<0.05) in G2 and G4, although with higher values (P<0.05) on day 60. The volume of lymphatic space was higher (P<0.05) in G2 and G4, being day 60 higher (P<0.05) than day 15. Greater preservation and recovery of seminiferous epithelium occurred in G4, compared to G2. Conclusion: Thus, the GTE administration is an effective way to improving tissue recovery after testicular damage, induced by short-term heat.
Influência da temperatura sobre a função testicular[Influence of temperature on testicular function] Resumo As células da linhagem germinativa são sensíveis a ação do calor, sendo a termorregulação um fator determinante para o sucesso reprodutivo. O aumento da temperatura testicular pode ocorrer devido a fatores internos ou externos e contribui para o aumento da produção de espécies reativas de oxigênio e nitrogênio, induzindo, assim, a degeneração testicular e perda de células germinativas. Em adição, mudanças nos níveis de testosterona e de corticosteroides em animais submetidos ao estresse térmico podem ser observadas e interferem na capacidade reprodutiva dos mesmos. Por outro lado, em resposta ao calor e com finalidade protetora, há o aumento da síntese de proteínas de choque térmico (HSP). Desta forma, a quantidade e qualidade do sêmen e, consequentemente, a fertilidade são comprometidas pelo estresse térmico testicular, o que torna a realização de estudos que aprofundem o conhecimento sobre as alterações causadas indispensáveis, inclusive para a busca de terapias que preservem e reparem as funções testiculares.Palavras-chave: estresse térmico; degeneração testicular; HSPs; ROS. AbstractGerm cells are sensitive to heat, thus thermoregulation is a determinant factor for reproductive success. The increase in testicular temperature can occur due to internal or external factors and contributes to the increased production of reactive oxygen and nitrogen species, which induces testicular degeneration and loss of germ cells. Furthermore, changes in testosterone and corticosteroid levels in animals submitted to heat shock can be observed and compromises the reproductive capacity. On the other hand, in response to heat, as a protection, an increase in synthesis of heat shock proteins (HSP) is observed. Therefore, the semen quantity and quality , consequently, the fertility are compromised by high temperatures, which makes necessary studies that furthers the knowledge on the changes caused, and that search for therapies that preserve and repair the testicular functions.
Background: Embryo transfer is one of the most commonly used reproductive biotechnique. The success of embryo transfer is also affected by the synchrony of estrus and ovulation between donor and recipient animals. In horse reproduction, ultrasonography has been used, among other purposes, to diagnose early pregnancy. However, only the color Doppler imaging mode makes it possible to evaluate the vascular architecture and the hemodynamic aspects of the vessels in several organs, especially the corpus luteum. The objective of this study was to evaluate, based on the color Doppler ultrasound, the corpus luteum vascularization and function from recipient mares at embryo transfer timing.Materials, Methods & Results: Mangalarga Machador mares from 5 to 10-year-old and a range of live weights of between 350 to 450 kg were used for this experiment, kept in pasture-based on mombaça grass (Panicum maximum) and were given ad libitum access to water and mineral supplementation. The animals (n = 15) were gynecologically examined and uterine consistency was evaluated by rectal palpation the same operator using an ultrasound system (SonoScape®) with a linear transducer, and operating frequency ranging from 5 to 10 Mhz. The uterine tone was classified between grades 1 and 4 and subjected to ovulation induction. The objective and subjective vascular perfusion of the corpus luteum was evaluated by color Doppler ultrasound on the day of embryo transfer and endometrium. The determination progesterone concentration on the day of the embryo transfer was performed by direct chemiluminescence assay. The arcsine (√P/100) transformation was applied to the percentage data, and the results were expressed as mean (.) ± standard error of the mean (SEM). Further, the assumptions of normality and homoscedasticity were verified, respectively, based on the Shapiro-Wilk and Lilliefors tests. Regarding the parametric and non-parametric variables, were applied, respectively, analysis of variance (ANOVA) followed by Tukey’s test, and the Kruskal-Wallis test followed by Dunn’s test. Pearson’s correlation coefficient was used to evaluate the relationship between the parameters. The statistical program SPSS 16.0 was used to perform the over-mentioned analyses, and a p-value < 0.05 was taken as significant. Corpus luteum vascular perfusion, based on the objective and subjective evaluation methods, and the progesterone concentration were higher in the pregnant mares (P < 0.05). The objective and subjective methods for evaluation of the vascular perfusion in the corpus luteum were positively correlated between themselves as well as to progesterone concentration (P < 0.05). There was no significant difference between the groups considering the uterine tonus evaluation (P > 0.05).Discussion: Mares that later became pregnant showed a higher concentration of progesterone as an outcome of the higher vascularization in the corpus luteum. It can be supported by both the correlation between the progesterone concentration and the corpus luteum vascular perfusion, as well as by the higher values of the vascular perfusion in pregnant mares. Based on the results, it has been concluded that the color Doppler ultrasound evaluation is an accurate tool to determine the corpus luteum vascularization, whether considering the objective or subjective methods. Also, the vascular perfusion is the most efficient parameter to determine both the corpus luteum function and to predict the ability of the recipient mares to maintain pregnancy.
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