Addition of synthetic amino acids in sheep semen improves its quality after cryopreservation / Adição de aminoácidos sintéticos no sêmen ovino melhora a qualidade espermática após a criopreservação do sêmen

Some amino acids can protect mammalian sperm cells against oxidation during thermal stress caused by freezing/thawing. Thus, the objective was to evaluate the protective action of the association of the amino acids L-proline (Pro) and L-glutamine (Glu) against the cryoinjury caused to sheep sperm after cryopreservation. Eight ejaculates were collected from four sheep (n=32) and diluted in Tris-Egg Yolk-Glycerol until the final concentration of 200 x106 sptz/mL and kept in a water bath at 32 °C. The amino acids were added as follows: control (without adding amino acids), Pro+Glu 1 (100 µM Pro + 500 µM Glu), Pro+Glu 2 (300 µMPro + 1000 µM Glu), Pro+Glu 3 (500 µM Pro + 1500 µM Glu) and Pro+Glu 4 (700 µM Pro + 2000 µM Glu). Afterwards, the semen was cooled to 5 °C for 2 h, after that period, filled in 0.5 mL straws and then placed under liquid nitrogen vapor (N2L), 8 cm from the liquid sheet for 15min, and then immersed on the N2L. The samples were analyzed for sperm motility, plasma membrane and acrosomal membrane integrity, mitochondrial activity and binding test. The variables were subjected to the normality tests (Lilliefors test) and homoscedasticity tests (Cochran and Bartlett test), afterwards the variables of normal distribution were subjected to analysis of variance and the means compared by the Tukey test with a significance level of 5%. The Pro+Glu 3 group exhibited sperm with a greater (P<0.05) motility after thawing. In addition, the highest percentage of plasma and acrosomal membrane integrity were obtained using Pro+Glu 1, Pro+Glu 2 and Pro+Glu 3; and Pro+Glu 2 and Pro+Glu 3, respectively. Amino acids also kept mitochondrial activity high compared to the control, with Pro+Glu 3 resulting in greater activity (P<0.05). Sperm viability was higher (P<0.05) with the use of Pro+Glu 2 and Pro+Glu 3 than in the control. The number of sperm that showed the ability to bind to the egg yolk perivitelline membrane was higher (P<0.05) in semen treated with amino acids. It is concluded that the addition of synthetic amino acids in the semen of sheep before cryopreservation improves sperm quality and fertilization potential and can thus be added in cryopreservation protocols.

Alguns aminoácidos podem proteger as células espermáticas de mamíferos contra a oxidação durante o estresse térmico causado na congelação/descongelação. Dessa forma, objetivou-se avaliar a ação protetora da associação dos aminoácidos L-prolina (Pro) e L-glutamina (Glu) contra as crioinjúrias causadas aos espermatozoides de ovino após a criopreservação. Foram coletados oito ejaculados de quatro carneiros (n=32) e diluídos em Tris-Gema de ovo-Glicerol até a concentração final de 200 x106 sptz/mL e, mantidos em banho maria a 32 °C. Os aminoácidos foram adicionados da seguinte forma: controle (sem adição de aminoácidos), Pro+Glu 1 (100 µM Pro + 500 µM Glu), Pro+Glu 2 (300 µM Pro + 1000 µM Glu), Pro+Glu 3 (500 µM Pro + 1500 µM Glu) e Pro+Glu 4 (700 µM Pro + 2000 µM Glu). Depois, o sêmen foi resfriado a 5 °C por 2 h, após esse período, envasado em palhetas de 0,5 mL e então acondicionado sob vapor de nitrogênio líquido (N2L), a 8 cm da lâmina líquida por 15 min, e depois imersos no N2L. As amostras foram analisadas quanto à motilidade espermática, integridade da membrana plasmática e da membrana acrossomal, atividade mitocondrial e teste de ligação. As variáveis foram submetidas aos testes de normalidade (Teste de Lilliefors) e homocedacidade (Teste de Cochran e Bartlett), posteriormente as variáveis de distribuição normal foram submetidas à análise de variância e as médias comparadas pelo teste de Tukey com nível de significância de 5%. O grupo Pro+Glu 3 exibiu espermatozoides com uma maior (P<0,05) motilidade após o descongelamento. Além disso o maior percentual de integridade da membrana plasmatica e acrossomal foram obtidos utilizando Pro+Glu 1, Pro+Glu 2 e Pro+Glu 3; e Pro+Glu 2 e Pro+Glu 3, respectivamente. Os aminoácidos também mantiveram alta a atividade mitocondrial em comparação com o controle, com Pro+Glu 3 resultando numa maior atividade (P<0,05). A viabilidade dos espermatozoides foi maior (P<0,05) com o uso de Pro+Glu 2 e Pro+Glu 3 do que no controle. O número de espermatozoides que apresentaram à capacidade de ligação a membrana perivitelina da gema de ovo foi maior (P<0,05) no sêmen tratado com aminoácidos. Conclui-se que, a adição dos aminoácidos sintéticos no sêmen de ovinos antes da criopreservação melhora a qualidade espermática e o potencial fecundante, podendo assim serem adicionados em protocolos de criopreservação.

Actiflagelin, a new sperm activator isolated from Walterinnesia aegyptia venom using phenotypic screening

Background Sperm contains a wealth of cell surface receptors and ion channels that are required for most of its basic functions such as motility and acrosome reaction. Conversely, animal venoms are enriched in bioactive compounds that primarily target those ion channels and cell surface receptors. We hypothesized, therefore, that animal venoms should be rich enough in sperm-modulating compounds for a drug discovery program. Our objective was to demonstrate this fact by using a sperm-based phenotypic screening to identify positive modulators from the venom of Walterinnesia aegyptia. Methods Herein, as proof of concept that venoms contain interesting compounds for sperm physiology, we fractionated Walterinnesia aegyptia snake venom by RP-HPLC and screened for bioactive fractions capable of accelerating mouse sperm motility (primary screening). Next, we purified each compound from the positive fraction by cation exchange and identified the bioactive peptide by secondary screening. The peptide sequence was established by Edman sequencing of the reduced/alkylated compound combined to LC-ESI-QTOF MS/MS analyses of reduced/alkylated fragment peptides following trypsin or V8 protease digestion. Results Using this two-step purification protocol combined to cell phenotypic screening, we identified a new toxin of 7329.38 Da (actiflagelin) that activates sperm motility in vitro from OF1 male mice. Actiflagelin is 63 amino acids in length and contains five disulfide bridges along the proposed pattern of disulfide connectivity C1-C5, C2-C3, C4- C6, C7-C8 and C9-C10. Modeling of its structure suggests that it belongs to the family of three finger toxins with a noticeable homology with bucandin, a peptide from Bungarus candidus venom. Conclusions This report demonstrates the feasibility of identifying profertility compounds that may be of therapeutic potential for infertility cases where motility is an issue.

Star anise extracts modulation of reproductive parameters, fertility potential and DNA fragmentation induced by growth promoter Equigan in rat testes

ABSTRACT Equigan is an anabolic steroid that has been developed for veterinary use and derived from endogenous sex hormone testosterone that plays a key role in the development of male reproductive tissue as well as in puberty and spermatogenesis. The current study is aimed to investigate the possible prophylactic effect of star anise extracts (SAE) on the toxicity of rat testes, sexual hormones alternations, sperm count, sperm abnormalities and testicular DNA damage by Equigan. Forty adult male rats were equally divided into four groups (1st Control group, 2nd SAE group, 3rd Equigan and 4th Equigan+SAE group). Food and fluid intakes, relative body weight, potassium, chloride, phosphorous, non-progressive and immotile sperms were significantly increased in Equigan group as compared to control group. In contrast; relative testes weight, sodium, magnesium, total calcium, testosterone, FSH, LH, PRL, sperm count, progressive motility, and viability showed a significant decrease in Equigan group as compared to control groups. The relative weight of epididymis, seminal vesicles, prostates and serum calcium ions didn't change significantly in different studied groups. Co-administration of SAE with Equigan improved the sexual toxicity, electrolyte alternations, sperm count, abnormalities and DNA damage induced by Equigan.

Short-term buserelin administration induces apoptosis and morphological changes in adult rat testes

Abstract Purpose: To investigate the effect of buserelin on gonadal structure and function in adult male rats. Methods: Twenty-four adult Wistar male rats were divided into three groups: two treated groups and controls. The first and second treated groups received 300 (low dose) and 500 (high dose) µg/kg buserelin, respectively, and the control group received normal saline. All groups were treated subcutaneously for five days. Results: The seminiferous tubular epithelial thickness was significant decreased in the treated groups compared with those in the control. There was a significant increase in apoptotic cell death in high dose treated group compared with low dose treated and control groups. No significant difference in serum testosterone level was observed after one month in the three groups. Conclusion: Buserelin induces apoptotic cell death and decreased diameter and epithelium thickness of seminiferous tubules in the adult rat testes.

Interacción de los péptidos opiodes endógenos con la función del eje hipotálamo-hipófisis-testículo / Interaction of endogenous opoid peptides with hypothalamie-hypophisis-testis axis function

A partir del aislamiento e identificación de sustancias endógenas con actividad opoide (endorfinas y encefalinas) (1), y del descubrimiento de los receptores opoides en el cerebro de mamíferos (2), numerososo estudios se han realizado con el fin de conocer el papel que estos opoides endógenos tienen en la regulación neuroendocrina del eje hipotálamo-hipófisis-gónada. Tanto los opioides endógenos como los agentes químicos con actividad opoide (morfina, heroína, metadona, análogo sintéticos de encefalinas, etc.) interfieren con la producción de las hormonas secretadas por la hipófisis; el efecto de estos opoides es inhibitorio para algunas hormonas como la LH, FSH y la TSH, mientras que para otras como la PRL, GH y ACTH estimulan su producción (3), los opoides actúan a nivel hipotalámico y suprahipotalámico modulando la secreción de factores liberadores e inhibitorios. En varones adultos sanos los péptidos opioides endógenos (POE) produce una disminución de los niveles séricos de gonadotrofinas. La administración de antagonistas específicos de los receptores opiáceos aumentan la liberación de hormona luteinizante (LH) e incrementan la freuencia y amplitud de los pulsos de LH (6). Tanto los efectos de los POE como de los antagonistas específicos de sus receptores están alterados en la diferentes patologías del eje hipotálamo-hipófisis-testículo