Sêmen congelado e inseminação artificial em cães
Arquivos
Data
2016-08-03
Autores
Sicherle, Carmen Cecilia [UNESP]
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ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
O objetivo deste estudo foi o de avaliar os efeitos da criopreservação sobre a qualidade e fertilidade do sêmen de cão. Para isso foram realizados dois experimentos. No primeiro experimento foram colhidos 4 ejaculados de 5 cães (n=20), os quais foram avaliados no sêmen fresco, resfriado e descongelado. A motilidade total (MT), progressiva (MP) e porcentagem de rápidos (RAP) por sistema computadorizado e por citometria de fluxo, a fluidez da membrana plasmática [Yo-Pro 1 (YP) e merocianina 540 (M540)], a translocação da fosfatilidil serina (FS) (anexina V e FITC-PSA), integridade da membrana plasmática e acrossomal (iodeto de propídeo (IP) combinado ao FITC-PSA), potencial da membrana mitocondrial (JC1), lipoperoxidação dos lipídeos de membrana (LPO, C11-BODIPY) e apoptose (CellEvent®). O sêmen do cão que apresentou melhores resultados numéricos em todas as análises foi escolhido para ser utilizado separadamente para as inseminações (cão 1) e o sêmen dos demais 4 cães foram utilizados em pool. Foram inseminadas 20 cadelas (2 IAs/cadela), por via transcervical (TCIA) sendo 10 delas com o cão 1 e 10 com o pool. Foram utilizadas 2 concentrações espermáticas (160 e 450 x 106 espermatozoides/TCIA). Houve diferença para os índices de motilidade (p < 0,01) entre o sêmen fresco e resfriado quando comparados ao descongelado para todos os índices avaliados, (MT = 87,00 ± 1,24; 88,15 ± 1,38; 72,55 ± 6,26); (MP = 69,95 ± 1,28 ; 71,75 ± 1,91; 56,30 ± 6,00) e (RAP = 83,15 ± 1,94; 81,55 ± 1,53; 64,30 ± 7,68). Em relação a fluidez da membrana espermática houve diferença na porcentagem da população de células íntegras (CI) e de células com aumento de fluidez de membrana (CIMF) (p < 0,01) entre o sêmen fresco e resfriado quando comparados ao descongelado, (CI = 78,29 ± 6,22; 75,76 ± 6,60; 23,02 ± 9,12); (CIMF = 18,33 ± 5,54; 22,55 ± 6,49; 71,78 ± 9,85). Sobre a identificação da translocação da FS houve diferença (p < 0,01) na porcentagem de células íntegras nos 3 momentos avaliados (CI = 79,90 ± 7,95; 63,50 ± 4,66; 27,19 ± 9,22). A porcentagem de células apresentado a membrana plasmática e acrossomal íntegras foi diferente (p < 0,01) também entre o sêmen fresco e resfriado quando comparados ao descongelado (MPAI = 85,71 ± 6,22; 70,37 ± 6,43; 30,87 ± 9,90). Quanto ao potencial da membrana mitocondrial houve diferença (p < 0,01) na porcentagem de células com alto potencial mitocondrial nos 3 momentos avaliados (APM = 85,15 ± 2,76; 60,52 ± 3,31; 38,06 ± 6,40). A LPO da membrana plasmática foi diferente (p < 0,05) no sêmen congelado quando comprado ao resfriado mas não teve diferença entre o sêmen fresco e resfriado e do fresco ao congelado. Não foi observada qualquer diferença, nos momentos estudados, na atividade da caspase. O cão 1 foi significamente melhor para os índices de integridade de membrana plasmática e acrossomal e potencial mitocondrial. Pelo calculo da resposta média do animal e limites mínimos e máximos, apesar de não haver diferença, observamos que o animal 1 apresentou melhores valores pós descongelação para todas os testes realizados. O aumento na concentração espermática foi positivo e observamos 50% de prenhez no grupo inseminado com o pool de sêmen utilizando a concentração de 450 x 106. Nenhuma gestação foi observada nas TCIA com o sêmen do cão 1. Em conclusão a criopreservação leva a alterações estruturais e funcionais da célula espermática, o que explica a sua sobrevivência curta após a descongelação. As mudanças semelhantes a crio-capacitação podem estar relacionadas a outros fatores, como as proteínas do plasma seminal que ainda não são totalmente conhecidas nesta espécie. O processo de apoptose pode ser iniciado com a abertura dos poros mitocondriais durante o processo de congelação/descongelação, o que libera fatores pro-apoptóticos no citoplasma celular. O potencial mitocondrial não está relacionado com a motilidade dos espermatozoides, mas sim com a sobrevivência do espermatozoide. Melhores resultados de gestação puderam ser obtidos quando mais de 100 x 106 de espermatozoides móveis e morfologicamente íntegros for utilizados por TCIA. Não houve relação entre a qualidade seminal, avaliada pelas técnicas aqui descritas, e a fertilidade.
The aims of the study were to assess individual characteristics and sperm concentration of cryopreserved semen characteristics using different structural and functional analysis and dog fertility. Twenty ejaculates were collected from 5 dogs and sperm were cryopreserved by one-step protocol. To better understand dog semen quality after thawing five healthy mature dogs were used to the one-step sperm cryopreservation protocol. Sperm analysis was performed at three time points: after collection, refrigeration, and after thawing, by computer sperm motility analysis (total [TM] and progressive motility [PM], and rapid sperm), membrane damage (membrane fluidity and viability - Yo-Pro 1 and merocianina 540, phosphatidyl serine translocation – annexin – V – propidium iodide - PI, acrosomal and membrane integrity FITC-PSA – PI), mitochondrial potential (JC-1), membrane lipid peroxidation, LPO (BODIPY 581/591 C11) and apoptosis (kit CellEventTM Caspase-3/7- FITC Green Flow Cytometry), evaluated by flow cytometry. Twenty bitches were inseminated by transcervical intrauterine (TCAI), twice using 2 sperm concentration (160 and 450 x 106 spermatozoa/TCAI). A decrease on frozen/thawed semen comparing to fresh and cooled semen occurred for the parameters of total and progressive motility (TM 87.00 ± 1.24, 88.15 ± 1.38, 72.55 ± 6.26; PM 69.95 ± 1.28, 71.75 ± 1.91, 56.30 ± 6.00, fresh cooled and frozen/thawed respectively P < 0.01), percentage of rapids (83.15 ± 1.94, 81.55 ± 1.53, 64.30 ± 7.68 P < 0.01), membrane fluidity and cell viability (78.29 ± 6.22, 75.76 ± 6.60, 23.02 ± 9.12 P < 0.01) and acrosomal and membrane integrity (85.71 ± 6.22, 70.37 ± 6.43, 30.87 ± 9.90 P < 0.01). Sperm cells were affect for cooling and freezing process when analyzed for the translocation of phosphatidyl serine (79.90 ± 7.95, 63.50 ± 4.66, 27.19 ± 9.22 P < 0.01) and high mitochondrial potential (85.15 ± 2.76, 60.52 ± 3.31, 38.06 ± 6.40 P < 0.01). For LPO significant difference was observed in semen after thawing only comparing to cooled semen (16.57 ± 5.44, 16.22 ± 2.43, 23.00 ± 4.13 P < 0.05). No difference on caspase activity was observed. Dog 1 was significantly better for the parameters of plasma membrane and acrosome integrity and mitochondrial potential. By calculating the average of the animal response and minimum and maximum limits, although there is no difference, we observed that the semen from Dog 1 displayed better post thaw values for all analyzes. The pregnancy rate was 0% for dog 1 and 50% for pool at concentration 450 x 106 spermatozoa. In conclusion, cryopreservation leads to structural and functional changes in sperm cell, which explains their short survival after thawing. The cryo-capacitation like changes can be related to others factors, as the seminal plasma proteins that are not know yet on this species. Apoptosis process can be initiated with the opening of mitochondrial pores during the freezing/thaw process, which releases pro-apoptotic factor on the cytoplasm. The mitochondrial potential is not related to sperm motility but sperm survival. Although the dog 1 displayed better sperm quality, no pregnancy was observed, which makes us to rethink the prediction of fertility of semen samples by commonly used parameters. The concentration dose used for AI procedures must consider motility and sperm viability to satisfactory pregnancy rates.
The aims of the study were to assess individual characteristics and sperm concentration of cryopreserved semen characteristics using different structural and functional analysis and dog fertility. Twenty ejaculates were collected from 5 dogs and sperm were cryopreserved by one-step protocol. To better understand dog semen quality after thawing five healthy mature dogs were used to the one-step sperm cryopreservation protocol. Sperm analysis was performed at three time points: after collection, refrigeration, and after thawing, by computer sperm motility analysis (total [TM] and progressive motility [PM], and rapid sperm), membrane damage (membrane fluidity and viability - Yo-Pro 1 and merocianina 540, phosphatidyl serine translocation – annexin – V – propidium iodide - PI, acrosomal and membrane integrity FITC-PSA – PI), mitochondrial potential (JC-1), membrane lipid peroxidation, LPO (BODIPY 581/591 C11) and apoptosis (kit CellEventTM Caspase-3/7- FITC Green Flow Cytometry), evaluated by flow cytometry. Twenty bitches were inseminated by transcervical intrauterine (TCAI), twice using 2 sperm concentration (160 and 450 x 106 spermatozoa/TCAI). A decrease on frozen/thawed semen comparing to fresh and cooled semen occurred for the parameters of total and progressive motility (TM 87.00 ± 1.24, 88.15 ± 1.38, 72.55 ± 6.26; PM 69.95 ± 1.28, 71.75 ± 1.91, 56.30 ± 6.00, fresh cooled and frozen/thawed respectively P < 0.01), percentage of rapids (83.15 ± 1.94, 81.55 ± 1.53, 64.30 ± 7.68 P < 0.01), membrane fluidity and cell viability (78.29 ± 6.22, 75.76 ± 6.60, 23.02 ± 9.12 P < 0.01) and acrosomal and membrane integrity (85.71 ± 6.22, 70.37 ± 6.43, 30.87 ± 9.90 P < 0.01). Sperm cells were affect for cooling and freezing process when analyzed for the translocation of phosphatidyl serine (79.90 ± 7.95, 63.50 ± 4.66, 27.19 ± 9.22 P < 0.01) and high mitochondrial potential (85.15 ± 2.76, 60.52 ± 3.31, 38.06 ± 6.40 P < 0.01). For LPO significant difference was observed in semen after thawing only comparing to cooled semen (16.57 ± 5.44, 16.22 ± 2.43, 23.00 ± 4.13 P < 0.05). No difference on caspase activity was observed. Dog 1 was significantly better for the parameters of plasma membrane and acrosome integrity and mitochondrial potential. By calculating the average of the animal response and minimum and maximum limits, although there is no difference, we observed that the semen from Dog 1 displayed better post thaw values for all analyzes. The pregnancy rate was 0% for dog 1 and 50% for pool at concentration 450 x 106 spermatozoa. In conclusion, cryopreservation leads to structural and functional changes in sperm cell, which explains their short survival after thawing. The cryo-capacitation like changes can be related to others factors, as the seminal plasma proteins that are not know yet on this species. Apoptosis process can be initiated with the opening of mitochondrial pores during the freezing/thaw process, which releases pro-apoptotic factor on the cytoplasm. The mitochondrial potential is not related to sperm motility but sperm survival. Although the dog 1 displayed better sperm quality, no pregnancy was observed, which makes us to rethink the prediction of fertility of semen samples by commonly used parameters. The concentration dose used for AI procedures must consider motility and sperm viability to satisfactory pregnancy rates.
Descrição
Palavras-chave
Cão, Espermatozoide, Criopreservação, Viabilidade, Espermática, Fertilidade, Dog, Sperm, Cryopreservation, Viability, Fertility, Intrauterine insemination