RESUMO
The aim of this study was to investigate the effects of sucrose on post-thawed equine semen quality. Semen samples (n = 24) were collected from six stallions. They were diluted (200 × 106 sperm/mL) in a freezing medium based on skimmed milk, egg yolk, dimethylformamide, and supplemented with sucrose at concentrations of 0 (Control), 25, 50, and 100 mM and in a commercial extender (BotuCrio). Subsequently, they were filled in straws (0.5 mL) and subjected to freezing and storage (-196°C). Immediately after thawing (37°C, 30 seconds), semen samples were evaluated for kinetics (CASA), plasma and acrosomal membrane integrity, and mitochondrial membrane potential (flow cytometry). The addition of 50 and 100mM sucrose to the freezing extender increased (P < .05) the parameters of TM, PM, VCL, VSL, and VAP, compared to the control group. The WOB parameter of the group supplemented with 100 mM sucrose was higher (P < .05) than the control group. Higher values ââ(P < .05) of ALH and BCF were observed in groups treated with sucrose (25, 50, and 100 mM), compared to BotuCrio. The semen frozen in the presence of 100 mM sucrose presented higher percentages (P < .05) of sperm with intact plasma and acrosomal membranes, and high mitochondrial membrane potential in relation to the other groups. It is concluded that the addition of sucrose to equine semen freezing extender increase motility (50 and 100 mM), plasma and acrosomal membrane integrity preserve, and high sperm mitochondrial membrane potential (100 mM) after thawing.
Assuntos
Crioprotetores , Análise do Sêmen , Animais , Criopreservação/veterinária , Crioprotetores/farmacologia , Dimetilformamida/farmacologia , Congelamento , Cavalos , Masculino , Análise do Sêmen/veterinária , Espermatozoides , Sacarose/farmacologiaRESUMO
l-Carnitine (LC) plays a key role in sperm metabolism, easily providing energy through ß-oxidation, which positively affects motility. The objective of this study was to investigate the association between blood plasma and seminal plasma LC levels, as well as the effect of LC as an additive in a skimmed milk-based extender during sperm storage at 5°C. In the first experiment, semen and blood samples from 14 Quarter Horse stallions were used. The LC content in blood plasma and seminal plasma was determined by spectrophotometry and their relationships with seminal parameters were evaluated. In the second experiment, ejaculates (n = 16) from four Quarter Horses were used. Each ejaculate was split into four treatment groups with different LC concentrations: 0 (control), 0.5, 1.0, and 2.0 mM. Sperm motility, integrity of plasma and acrosomal membranes, intracellular reactive oxygen species content, and plasma membrane stability were evaluated immediately after samples reached 5°C (0 hour) and after 24, 48, and 72 hours. There was a positive correlation (p < 0.05) between LC levels in seminal plasma with both sperm concentration and plasma and acrosomal membrane integrity. Furthermore, the addition of LC (1 and 2 mM) preserved the motility of equine sperm stored at 5°C. It was concluded that the concentrations of LC with seminal plasma present correlate to semen parameters and the addition of LC to skimmed milk-based extender preserves the motility of equine sperm stored at 5°C for up to 48 hours.
Assuntos
Preservação do Sêmen , Motilidade dos Espermatozoides , Animais , Carnitina , Cavalos , Humanos , Masculino , Sêmen , Análise do Sêmen , EspermatozoidesRESUMO
Recent studies have shown that adiponectin, an adipokine predominantly produced by adipose tissue, regulates several reproductive processes. However, the mechanisms of action of adiponectin on the maturation of goat oocytes remain to be determined. The aim of this study was to investigate whether (a) adiponectin influences the meiotic maturation of goat oocytes; (b) MAPK MEK 1/2 mediates the effects of adiponectin; and 3) adiponectin differentially affects mRNA relative abundance of genes relevant for adiponectin signal transduction in goat oocytes. The addition of adiponectin (5 µg/ml) during the maturation of goat oocytes resulted in a higher percentage of successful nuclear maturation compared to those of the group without adiponectin (p < 0.05). Adiponectin-stimulated nuclear oocyte maturation was significantly impaired by a mitogen-activated protein kinase MEK 1/2 inhibitor, U0126 (p < 0.05). There was no evidence of any adiponectin-induced difference in the relative transcript abundances of AdipoR1, AdipoR2, AMPKα1, AMPKα2, PPARα and PPARγ genes. In conclusion, these results indicate that adiponectin has a positive effect on the meiotic maturation of goat oocytes through the MAPK MEK 1/2 pathway. Furthermore, the adiponectin does not affect the relative abundance of genes relevant for adiponectin signal transduction in goat oocytes.
Assuntos
Adiponectina/farmacologia , Desenvolvimento Embrionário/efeitos dos fármacos , Técnicas de Maturação in Vitro de Oócitos/veterinária , Oócitos/efeitos dos fármacos , Transdução de Sinais , Animais , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Cabras , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Oócitos/fisiologia , Oogênese/efeitos dos fármacosRESUMO
The addition of antioxidants to semen cryopreservation extenders has been employed for combating oxidative damage. This work aimed to evaluate the addition of carotenoid canthaxanthin to a cryopreservation extender of ram semen. Three breeder rams were used and, after semen collection, with 48-hour intervals between collection, the samples were included in the pool formation (n = 6). The experimental groups comprised 0 (control), 0.1, 1, 10, and 25 µM of canthaxanthin. After thawing (37°C/30 s) and incubation at 37°C for 2 hours, semen aliquots from each group were evaluated for sperm kinetics (CASA), the integrity of the plasma and acrosomal membranes (iPAM), intracellular reactive oxygen species (ROS) production, and lipid peroxidation (LPO) by flow cytometry associated with the image. The control group and canthaxanthin 1 µM after incubation at 37°C for 2 hours showed increases of curvilinear velocity and amplitude of lateral head displacement with decreases of linearity, straightness, and wobble (p < 0.05), which were not observed for the canthaxanthin 10 and 25 µM. The supplementation of a Tris-egg yolk extender with canthaxanthin had no effect on the iPAM, intracellular ROS production in viable spermatozoa, or LPO. In conclusion, supplementation with 10 and 25 µM of canthaxanthin in a Tris-egg yolk extender used for ram semen cryopreservation is able to protect ovine sperm from kinetic changes after incubation at 37°C for 2 hours post-thawing.