Da coenzima Q10 sobre a viabilidade espermática de garanhões resistentes ou sensíveis à congelação
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Data
2017-07-18
Autores
Carneiro, João Alexandre Matos [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Entre as vantagens da criopreservação seminal, destacam-se a otimização do uso de garanhões com comprovada superioridade genética, pela possibilidade do armazenamento de sêmen mesmo fora da estação de monta e a quebra das barreiras geográficas, que torna possível a remessa deste material para qualquer parte do mundo. Contudo, o processo de congelação de sêmen causa danos à célula espermática, sendo a peroxidação lipídica e o estresse oxidativo, ocasionada pela produção anormal de espécies reativas de oxigênio (EROs), as principais injúrias. Desta maneira, para se obter uma melhor qualidade seminal após a descongelação, é necessário adicionar aos diluentes seminais elementos que desempenhem função antioxidante, visando conter o aumento dos níveis dos agentes oxidantes. Coenzima Q10 (CoQ10) é um agente lipossolúvel promotor de energia, tendo como principal função transportar prótons e elétrons no processo de síntese de ATP na membrana mitocondrial interna, através da cadeia de transporte de elétrons. Ainda, a CoQ10 atua como um potente antioxidante em diversos sistemas biológicos, tais como, lipoproteínas e membranas, protegendo-os contra a oxidação, inibindo a formação de hidroperóxidos e, consequentemente, prevenindo a peroxidação lipídica. Desta forma, o objetivo deste estudo foi avaliar a ação da coenzima Q10 (CoQ10) no espermatozoide de garanhões resistentes (RC) e sensíveis (SC) a congelação. Cada ejaculado (n=24) foi dividido em nove tratamentos e submetido à congelação, sendo a CoQ10 adicionada ao diluente de centrifugação, nas concentrações de 25 μmol/L (CE25), 50 μmol/L (CE50), 75 μmol/L (CE75) e 100 μmol/L (CE100), ou ao de congelação nas mesmas concentrações, 25 μmol/L (FE25), 50 μmol/L (FE50), 75 μmol/L (FE75) e 100 μmol/L (FE100). No grupo controle não houve adição da CoQ10 em nenhum dos meios diluentes. O processo de descongelação foi realizado à 37ºC/30 segundos (T0) e, para avaliação após estresse térmico, 37ºC/30minutos (T30). Posteriormente, as células espermáticas foram avaliadas quanto a cinética, integridade da membrana plasmática (IMP), desestabilização da membrana (NCAP), produção de espécies reativas ao oxigênio (H2O2 e O2 -), atividade mitocondrial e peroxidação lipídica. De acordo com os resultados, não houve diferença significativa entre os grupos, tanto no momento T0 quanto no momento T30, para os garanhões classificados como RC (p>0,05), com exceção da peroxidação lipídica, que em ambos os momentos, os grupos tratados apresentaram valores menores quando comparados ao controle (p<0,05). Já para os animais classificados como SC, houve uma superioridade das células espermáticas tratadas com a CoQ10 (p<0,05), com exceção da concentração de O2 - e potencial mitocondrial no T0, em que não apresentaram diferença entre os grupos (p>0,05). As células espermáticas do grupo CE75 se mostraram superiores aos parâmetros avaliados em relação aos demais grupos. Podemos concluir que a CoQ10 promove uma diminuição do estresse oxidativo e maior viabilidade ao espermatozoide de garanhões sensíveis ao processo de congelação espermática.
Among the advantages of seminal cryopreservation, the optimization of using stallions with proven genetic superiority, the possibility of storing semen even outside the breeding season and the breaking of geographical barriers, which makes it possible to send this material to any part of the world can de highlighted. However, the process of semen freezing causes damage to the sperm cell, and the abnormal production of reactive oxygen species is caused by lipid peroxidation of the sperm membrane, which is a major cause of such injury. Thus, in order to obtain a better seminal quality after thawing, it is necessary to add to the diluents substances that play an antioxidant function, limiting levels of the oxidizing agents increase. Coenzyme Q10 is a liposoluble energy-promoting agent, whose main function is to transport protons and electrons in the process of ATP synthesis in the internal mitochondrial membrane, through the electron transport chain. Furthermore, CoQ10 (ubiquinol) acts as a potent antioxidant in several biological systems, such as lipoproteins and membranes, protecting them against oxidation, inhibiting the hydroperoxides formation and, consequently, preventing lipid peroxidation. In this way, the objective of this study was to discuss how CoQ10 may help reducing the oxidative stress caused by seminal cryopreservation process. This form, the objective of this study was to evaluate the antioxidant action of coenzyme Q10 (CoQ10) on spermatozoa from good freezers (GF) and bad freezers (BF) stallions. Each ejaculate (n=15) was divided into nine treatments and subject to freezing process. The CoQ10 was added to centrifugation extender at concentrations 25 μmols/L (CE25), 50 μmols/L (CE50), 75 μmols/L (CE75) and 100 μmols/L (CE100), or at the freezer extender at the same concentrations, 25 μmols/L (FE25), 50 μmols/L (FE50), 75 μmols/L (FE75) and 100 μmols/L (FE100). In the control group there was no addition of CoQ10 in any of the extenders. The thawing process was performed at 37ºC/30 seconds (T0) and at 37ºC/30 minutes (T30). Posteriorly, sperm cells were evaluated for kinetics, plasma membrane integrity (PMI), membrane desestabilization (NCAP), reactive oxygen species production (H2O2 and O2 -), mitochondrial activity and lipid peroxidation. According to the results, there was no significant difference between the groups, as well T0 moment as T30 moment, for good freezer stallions (p>0.05). However for bad freezer stallions, there was a superiority of the sperm cells that came into contact with CoQ10 (p <0.05), except for the O2 - concentration and mitochondrial potential (T0) in which there was no significant difference between the Groups (p> 0.05). The sperm cells of the CE75 group were superior in the evaluated parameters in relation to the other groups. We can conclude that CoQ10 promotes a reduction of oxidative stress and greater viability to the spermatozoa from bad freezer stallions at the freezing process.
Among the advantages of seminal cryopreservation, the optimization of using stallions with proven genetic superiority, the possibility of storing semen even outside the breeding season and the breaking of geographical barriers, which makes it possible to send this material to any part of the world can de highlighted. However, the process of semen freezing causes damage to the sperm cell, and the abnormal production of reactive oxygen species is caused by lipid peroxidation of the sperm membrane, which is a major cause of such injury. Thus, in order to obtain a better seminal quality after thawing, it is necessary to add to the diluents substances that play an antioxidant function, limiting levels of the oxidizing agents increase. Coenzyme Q10 is a liposoluble energy-promoting agent, whose main function is to transport protons and electrons in the process of ATP synthesis in the internal mitochondrial membrane, through the electron transport chain. Furthermore, CoQ10 (ubiquinol) acts as a potent antioxidant in several biological systems, such as lipoproteins and membranes, protecting them against oxidation, inhibiting the hydroperoxides formation and, consequently, preventing lipid peroxidation. In this way, the objective of this study was to discuss how CoQ10 may help reducing the oxidative stress caused by seminal cryopreservation process. This form, the objective of this study was to evaluate the antioxidant action of coenzyme Q10 (CoQ10) on spermatozoa from good freezers (GF) and bad freezers (BF) stallions. Each ejaculate (n=15) was divided into nine treatments and subject to freezing process. The CoQ10 was added to centrifugation extender at concentrations 25 μmols/L (CE25), 50 μmols/L (CE50), 75 μmols/L (CE75) and 100 μmols/L (CE100), or at the freezer extender at the same concentrations, 25 μmols/L (FE25), 50 μmols/L (FE50), 75 μmols/L (FE75) and 100 μmols/L (FE100). In the control group there was no addition of CoQ10 in any of the extenders. The thawing process was performed at 37ºC/30 seconds (T0) and at 37ºC/30 minutes (T30). Posteriorly, sperm cells were evaluated for kinetics, plasma membrane integrity (PMI), membrane desestabilization (NCAP), reactive oxygen species production (H2O2 and O2 -), mitochondrial activity and lipid peroxidation. According to the results, there was no significant difference between the groups, as well T0 moment as T30 moment, for good freezer stallions (p>0.05). However for bad freezer stallions, there was a superiority of the sperm cells that came into contact with CoQ10 (p <0.05), except for the O2 - concentration and mitochondrial potential (T0) in which there was no significant difference between the Groups (p> 0.05). The sperm cells of the CE75 group were superior in the evaluated parameters in relation to the other groups. We can conclude that CoQ10 promotes a reduction of oxidative stress and greater viability to the spermatozoa from bad freezer stallions at the freezing process.
Descrição
Palavras-chave
Antioxidante, Sêmen, Criopreservação, Equino, Antioxidant, Semen, Cryopreservation, Equine