Adaptação respiratória neonatal: avaliação clínica, hemogasométrica e do estresse oxidativo de bezerros recém-nascidos provenientes de inseminação artificial, fertilização in vitro e clonagem animal
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Data
2018-03-23
Autores
Dantas, Gabriela Nascimento
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Universidade Estadual Paulista (Unesp)
Resumo
O sucesso da adaptação neonatal ocorre com o estabelecimento da função respiratória. Fisiologicamente, o neonato passa do ambiente hipóxico uterino para a hiperoxia do ar respirado após o nascimento. Assim, são produzidos radicais livres provenientes do oxigênio que estão relacionados ao aparecimento do estresse oxidativo, condição associada com diversas enfermidades. Bezerros originados por Fertilização In Vitro (FIV) e Clonagem Animal (CA) podem apresentar problemas ao nascimento e, devido ao seu alto valor genético e econômico, requerem do Médico Veterinário diagnóstico precoce e terapia eficaz em caso de má-adaptação neonatal. O objetivo deste trabalho foi comparar a influência de três métodos de concepção (Inseminação Artificial - IA, FIV e CA) sobre o status oxidativo, função pulmonar e adaptação pós-natal de recém-nascidos da espécie bovina. Para isso, foram utilizados 20 bezerros hígidos provenientes de IA, 15 neonatos originados por FIV e 15 recém-nascidos oriundos de CA. Todos os 50 animais foram monitorados do nascimento até 48 horas de vida, com avaliações realizadas com zero, seis, 12, 24 e 48 horas de vida. Nesses momentos, foram realizados: exame físico, hemogasometria (mensuração de pH, pressões parciais de oxigênio e de gás carbônico, bicarbonato, saturação de oxigênio, dióxido de carbono total e excesso de base) e verificação dos biomarcadores do status oxidativo (determinação das atividades enzimáticas da Superóxido Dismutase - SOD, Catalase e Glutationa Peroxidase – GSH-Px, e das concentrações de Glutationa Total e Substâncias Reativas ao Ácido Tiobarbitúrico no sangue periférico por espectrofotometria). Ao nascimento também foram avaliados o Escore Apgar e medidas de comprimento de coluna e amplitude respiratória. Foi demonstrado que bezerros clonados possuem maior peroxidação lipídica causada pelo aumento da produção de radicais livres associado à diminuição da atividade da SOD. Além disso, os neonatos FIV tiveram maior atividade das enzimas antioxidantes Catalase e GSH-Px, seja por maior produção de peróxido de hidrogênio ou por resposta enzimática mais eficiente. Os bezerros do Grupo IA mostraram maiores valores para o Grupo Tióis Reduzidos (relacionado à glutationa reduzida). Os clones apresentaram acidose pós-parto mais acentuada do que a acidose mista fisiológica esperada para neonatos, o que ficou evidente pela diminuição de HCO3 e BE e aumento do TCO2 quando comparado aos demais grupos. Esse distúrbio refletiu-se na diminuição do escore Apgar e no aumento das frequências cardíaca e respiratória. Desta forma, o Grupo CA apresentou pior adaptação respiratória neonatal do que os outros grupos, e, por este motivo, necessita de acompanhamento intensivo, monitoramento através da realização de exames clínico e hemogasométrico repetidos e tratamento precoce apropriado, de maneira a assegurar a saúde desses animais.
The success of neonatal adaptation is directly related to the establishment of respiratory function that allows efficient gas exchange. Physiologically, the neonate abruptly passes from the hypoxic uterine environment to the hyperoxic air breathed after birth. With this, free radicals are produced from oxygen that may be related to the appearance of oxidative stress, a condition that has been associated with several diseases. Calves produced by In Vitro Fertilization (FIV) and Animal Cloning (CA) present some problems at birth, and due to their high genetic and economic value, require the Veterinarian to diagnose early and effective therapy in case of neonatal maladaptation. The objective of this study was to compare the influence of the three conception methods (Artificial Insemination - IA, FIV and CA) on oxidative status, postnatal adaptation and lung function of newborns of the bovine species. For this, 20 healthy calves from IA (Control Group), 15 neonates originated by FIV and 15 newborns from CA were used. All 50 animals were monitored from birth to 48 hours of life, with evaluations performed at 0, 6, 12, 24 and 48 hours of life. At these moments, physical examination, hemogasometry (pH measurement, partial pressures of oxygen and carbon dioxide, bicarbonate, oxygen saturation, total carbon dioxide and base excess) were carried out and verification of biomarkers of oxidative status (determination of activities enzymes of Superoxide Dismutase - SOD, Catalase and Glutathione Peroxidase – GSH-Px, and Total Glutathione and Thiobarbituric Acid Substances in peripheral blood by colorimetric method). At birth, Apgar score and measurements of column length and respiratory amplitude were also performed. As results, it was obtained that cloned calves have higher production of free radicals by lipid peroxidation and that this factor was associated with a lower amount of SOD in this group. In addition, FIV neonates obtained higher concentrations of antioxidant enzymes with respect to Catalase and GSH-Px, either by higher production of hydrogen peroxide or by more efficient enzymatic response. Control Group calves showed higher values for reduced glutathione. In addition, the clones presented a more pronounced postpartum acidosis than the expected physiological acidosis expected for neonates, especially with regard to the metabolic component, which was evidenced by the changes in HCO3, TCO2 and BE when compared to the other groups. This disorder may have reflected Apgar score and heart and respiratory rates. Intensive follow-up of these infants is suggested for early diagnosis of respiratory maladaptation and correct treatment.
The success of neonatal adaptation is directly related to the establishment of respiratory function that allows efficient gas exchange. Physiologically, the neonate abruptly passes from the hypoxic uterine environment to the hyperoxic air breathed after birth. With this, free radicals are produced from oxygen that may be related to the appearance of oxidative stress, a condition that has been associated with several diseases. Calves produced by In Vitro Fertilization (FIV) and Animal Cloning (CA) present some problems at birth, and due to their high genetic and economic value, require the Veterinarian to diagnose early and effective therapy in case of neonatal maladaptation. The objective of this study was to compare the influence of the three conception methods (Artificial Insemination - IA, FIV and CA) on oxidative status, postnatal adaptation and lung function of newborns of the bovine species. For this, 20 healthy calves from IA (Control Group), 15 neonates originated by FIV and 15 newborns from CA were used. All 50 animals were monitored from birth to 48 hours of life, with evaluations performed at 0, 6, 12, 24 and 48 hours of life. At these moments, physical examination, hemogasometry (pH measurement, partial pressures of oxygen and carbon dioxide, bicarbonate, oxygen saturation, total carbon dioxide and base excess) were carried out and verification of biomarkers of oxidative status (determination of activities enzymes of Superoxide Dismutase - SOD, Catalase and Glutathione Peroxidase – GSH-Px, and Total Glutathione and Thiobarbituric Acid Substances in peripheral blood by colorimetric method). At birth, Apgar score and measurements of column length and respiratory amplitude were also performed. As results, it was obtained that cloned calves have higher production of free radicals by lipid peroxidation and that this factor was associated with a lower amount of SOD in this group. In addition, FIV neonates obtained higher concentrations of antioxidant enzymes with respect to Catalase and GSH-Px, either by higher production of hydrogen peroxide or by more efficient enzymatic response. Control Group calves showed higher values for reduced glutathione. In addition, the clones presented a more pronounced postpartum acidosis than the expected physiological acidosis expected for neonates, especially with regard to the metabolic component, which was evidenced by the changes in HCO3, TCO2 and BE when compared to the other groups. This disorder may have reflected Apgar score and heart and respiratory rates. Intensive follow-up of these infants is suggested for early diagnosis of respiratory maladaptation and correct treatment.
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Palavras-chave
Neonatologia Veterinária, Bovinos, Clone, Função Respiratória, Hemogasometria, Glutationa