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1.
Rev. bras. reprod. anim ; 45(4): 600-607, out.-dez. 2021. ilus
Artigo em Português | VETINDEX | ID: biblio-1492714

Resumo

A L-arginina (L-arg) é o principal precursor da síntese do NO, contudo, é precursora também da síntese de creatina, agmatina, ureia, síntese proteica, L-ornitina, poliaminas, L-prolina e L-glutamato. Nesta breve revisão, vamos falar de alguns resultados que estão sendo obtidos sobre o papel da L-arg na capacitação de espermatozoides bovinos e seu impacto na produção in vitro de embriões. Estudos in vitro mostraram que a adição de L-arg ao meio de capacitação espermática está associada a um aumento na produção de NO, que se correlaciona com aumento da motilidade e vigor, integridade da membrana plasmática e acrossomal, atividade mitocondrial, capacitação espermática, peroxidação lipídica, bem como com a produção de blastocistos. Além disso, a adição da L-arg ao meio de capacitação in vitro, altera o perfil de proteínas importantes ligadas ao processo de capacitação, fertilização e desenvolvimento embrionário inicial. Estes efeitos da L-arg são GMPc dependentes e independentes. Na maturação in vitro, entretanto, embora já tenham sido encontrados bons resultados com o uso do L-arg, mais estudos são necessários para determinar a concentração ideal a ser adicionada ao meio de maturação in vitro e seu impacto na produção de blastocistos. Visto que a pré-capacitação de espermatozoides induzida pela heparina em presença de L-arg foi o método mais eficiente na produção in vitro de embriões, sugerimos sua utilização. Mais pesquisas sobre o metabolismo da L-arg no espermatozoide e CCOs de bovinos durante eventos ligados à fertilização são necessários para se identificar novas vias que atuem nestas etapas in vitro visando o aumento da percentagem e qualidade de embriões bovinos produzidos in vitro.


L-arginine (L-arg) is the main source of NO synthesis; however, it is also a precursor of the synthesis of creatine, agmatine, urea, protein synthesis, L-ornithine, polyamines, L-proline, and Lglutamate. In this brief review, we will discuss some results obtained previously about the role of L-arg in the capacitation of bovine sperm and its impact on in vitro embryo production. In vitro studies have shown that the addition of L-arg to the sperm capacitation medium is associated with an increase in NO production, which in controlled levels is related to an increased motility and vigor, plasma and acrosomal membrane integrity, mitochondrial activity, sperm capacitation, peroxidation lipids, as well as with the blastocyst production. Furthermore, the addition of L-arg to the in vitro capacitation medium alters the profile of important proteins linked to the capacitation process, fertilization, and early embryonic development. These effects of L-arg are cGMP dependent and independent. In in vitro maturation, however, although good results have already been found with the use of L-arg, further studies are needed to determine the ideal concentration to be added to the in vitro maturation medium and its impact on the production of blastocysts. Since heparin-induced pre-capacitation of spermatozoa in the presence of L-arg was the most efficient method for in vitro embryo production, we suggest its use. More research on L-arg metabolism in bovine sperm and OCCs during events related to fertilization is needed to identify new pathways that act in these in vitro steps aiming to increase the percentage and quality of bovine embryos produced in vitro.


Assuntos
Masculino , Animais , Bovinos , Arginina/análogos & derivados , Blastocisto , Desenvolvimento Embrionário/fisiologia , Óxido Nítrico , Técnicas In Vitro
2.
Anim. Reprod. (Online) ; 16(4): 938-944, 2019. graf
Artigo em Inglês | VETINDEX | ID: biblio-1461481

Resumo

We aimed to evaluate the effects of L-arginine (L-arg) in the quality of in vitro heparin-induced capacitation of cryopreserved bovine spermatozoa and its effects on IVP. The experimental groups were: Control 0 hour without pre-capacitation, and groups of sperm capacitated for 30 min in the absence of COC with heparin (Control 30 min), with 1 mM L-arg and with 1 mM L-arg + heparin. The capacitation pattern was evaluated by chlortetracycline assay and the integrity of the plasma membrane (PM) and acrosome membrane (AM) by the association of Hoescht 33342 and propidium iodide. Further, we assess the sperm quality by the rate of in vitro blastocysts production. Treatment with 1 mM L-arg + heparin increased the percentage of capacitated sperm when compared to Control 0 hour and the treatment with heparin (61.1 vs. 18.2 and 47.0%, respectively, P0.05). The group capacitated with 1 mM L-arg + heparin for 30 min increased the blastocyst rate compared to Control IVF (53.7 vs. 40.8%, P<0.05). We conclude that the addition of L-arg with heparin increases the number of capacitated spermatozoa in vitro with 30 min of pre-incubation in the absence of COC not altering the integrity of plasma and acrosomal membrane. This treatment in the absence of COC was the most effective method for blastocysts production, and the method of pre-incubation could be used to assess the role of other substances in the sperm capacitation and its effect on IVP.


Assuntos
Masculino , Animais , Bovinos , Arginina/administração & dosagem , Arginina/análogos & derivados , Bovinos/anatomia & histologia , Bovinos/fisiologia , Capacitação Espermática , Técnicas In Vitro/veterinária , Desenvolvimento Embrionário , Óxido Nítrico
3.
Anim. Reprod. ; 16(4): 938-944, 2019. graf
Artigo em Inglês | VETINDEX | ID: vti-24181

Resumo

We aimed to evaluate the effects of L-arginine (L-arg) in the quality of in vitro heparin-induced capacitation of cryopreserved bovine spermatozoa and its effects on IVP. The experimental groups were: Control 0 hour without pre-capacitation, and groups of sperm capacitated for 30 min in the absence of COC with heparin (Control 30 min), with 1 mM L-arg and with 1 mM L-arg + heparin. The capacitation pattern was evaluated by chlortetracycline assay and the integrity of the plasma membrane (PM) and acrosome membrane (AM) by the association of Hoescht 33342 and propidium iodide. Further, we assess the sperm quality by the rate of in vitro blastocysts production. Treatment with 1 mM L-arg + heparin increased the percentage of capacitated sperm when compared to Control 0 hour and the treatment with heparin (61.1 vs. 18.2 and 47.0%, respectively, P<0.05). The addition of 1 mM L-arg to the medium has capacitated the spermatozoa (26.2 ± 3.8) but was less effective than heparin (47.0 ± 4.0) (P<0.05). There was no difference in the percentage of sperm with intact PM between treatments when compared to Control 0 hour (P>0.05). The group capacitated with 1 mM L-arg + heparin for 30 min increased the blastocyst rate compared to Control IVF (53.7 vs. 40.8%, P<0.05). We conclude that the addition of L-arg with heparin increases the number of capacitated spermatozoa in vitro with 30 min of pre-incubation in the absence of COC not altering the integrity of plasma and acrosomal membrane. This treatment in the absence of COC was the most effective method for blastocysts production, and the method of pre-incubation could be used to assess the role of other substances in the sperm capacitation and its effect on IVP.(AU)


Assuntos
Animais , Masculino , Bovinos , Arginina/análogos & derivados , Arginina/administração & dosagem , Capacitação Espermática , Técnicas In Vitro/veterinária , Bovinos/anatomia & histologia , Bovinos/fisiologia , Desenvolvimento Embrionário , Óxido Nítrico
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