Biosusceptometria de corrente alternada para avaliação da contratilidade uterina em ratas prenhes
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Data
2019-02-25
Autores
Simões, Luís Gustavo de Oliveira
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Universidade Estadual Paulista (Unesp)
Resumo
A contração uterina é um processo fisiológico espontâneo com impacto direto no ciclo menstrual/estral e na gestação. Disfunções na atividade uterina estão relacionadas com infertilidade, abortos e partos prematuros, sendo este último a maior causa de mortalidade e morbidade infantil no mundo. Sendo assim, se faz necessário o desenvolvimento de metodologias in vivo para monitorar o processo mecânico uterino. O objetivo deste trabalho foi aplicar a técnica de Biosusceptometria de Corrente Alternada para avaliação in vivo da atividade mecânica uterina em ratas prenhes. Foram utilizadas 40 ratas fêmeas Wistar prenhes com idade entre 10 e 15 semanas e com peso médio de 250 g. Através da Biosusceptometria de Corrente Alternada, 18 animais foram utilizados para avaliação da contratilidade uterina durante a prenhez e 8 foram usadas para avaliação da atividade uterina frente à ação da ocitocina. Na primeira etapa foi realizada uma cirurgia de fixação do marcador magnético em três posições da serosa uterina: próximo ao ovário; na região média entre o ovário e a cérvice; e próximo à cérvice. A atividade uterina foi monitorada nos dias 0, 7, 14, 20 e 21 de prenhez para cada posição do marcador. Na segunda etapa, foi realizado o implante do marcador magnético somente próximo à cérvice, e a atividade foi avaliada antes e depois da administração de ocitocina no dia 20 de prenhez. Os resultados obtidos foram perfis de contração para cada situação proposta, os quais apresentaram contrações basais de alta e baixa frequência e contrações intensas. Durante a evolução da prenhez, foi observado uma atividade discreta e irregular no primeiro terço, quiescência no segundo terço, transição no dia 20 e atividade intensa regular pré-parto. A ocitocina provocou a excitação da atividade uterina por meio da indução de contrações intensas e regulares, revelando um perfil similar ao obtido no dia 21 de prenhez. A análise dos resultados mostrou que o útero exibe perfis de contração distintos em cada etapa da prenhez, bem como uma evolução da atividade contrátil visando o desenvolvimento e expulsão do feto. Este trabalho fornece uma nova ferramenta para contribuir com novos estudos de patologias, hormônios e medicamentos que alterem a contratilidade normal uterina durante a gestação.
Uterine contraction is a spontaneous physiologic process with direct impact on menstrual/estrous cycle and pregnancy. Uterine activity dysfunction are related with infertility, abortion and premature birth, in which the last is the major cause of childish mortality and morbidity in the world. Therefore, in vivo methods to assess the mechanical process of the uterus under real physiologic condition remains necessary to be developed. The aim of this study was to apply Alternate Current Biosusceptometry to assess in vivo mechanical uterine activity of pregnant rats. Forty Wistar female pregnant rats with 10 to 15 weeks age and weighing 250 g were used. Through Alternate Current Biosusceptometry, 30 animals were used for uterine contraction analysis during pregnancy and 10 were used to evaluate uterine contractility due to oxytocin action. On the first part, an implant surgery was performed to fix the magnetic marker on uterus serous at three different position: near ovary; middle distance between ovary and cervix, and near cervix. Uterine peristalsis were measured at days 0, 7, 14, 20 and 21 of pregnancy. On the second part, magnetic marker was implanted only on near cervix and uterine activity was evaluated before and after the oxytocin administration on day 20 of pregnancy. Contraction profiles were obtained as results to each proposed analysis, in which presented high frequency and low frequency basal contraction and intense contractions. During pregnancy evolution, was observed a discreet and irregular activity on the first third, quiescence on the second third, transition on day 20 and intense and regular activity right before parturition. The oxytocin provoked uterine activity excitation by regular and intense contractions induction, revealing a similar profile obtained on day 21 of pregnancy. Results analysis demonstrated that uterus exhibits distinct contraction profile on each stage of pregnancy, as well as an evolution of contractile peristalsis aiming the development and fetus expelling. This work supply a new tool to contribute with new pathologies, hormones and drugs studies that modifies normal uterine contractility during gestation.
Uterine contraction is a spontaneous physiologic process with direct impact on menstrual/estrous cycle and pregnancy. Uterine activity dysfunction are related with infertility, abortion and premature birth, in which the last is the major cause of childish mortality and morbidity in the world. Therefore, in vivo methods to assess the mechanical process of the uterus under real physiologic condition remains necessary to be developed. The aim of this study was to apply Alternate Current Biosusceptometry to assess in vivo mechanical uterine activity of pregnant rats. Forty Wistar female pregnant rats with 10 to 15 weeks age and weighing 250 g were used. Through Alternate Current Biosusceptometry, 30 animals were used for uterine contraction analysis during pregnancy and 10 were used to evaluate uterine contractility due to oxytocin action. On the first part, an implant surgery was performed to fix the magnetic marker on uterus serous at three different position: near ovary; middle distance between ovary and cervix, and near cervix. Uterine peristalsis were measured at days 0, 7, 14, 20 and 21 of pregnancy. On the second part, magnetic marker was implanted only on near cervix and uterine activity was evaluated before and after the oxytocin administration on day 20 of pregnancy. Contraction profiles were obtained as results to each proposed analysis, in which presented high frequency and low frequency basal contraction and intense contractions. During pregnancy evolution, was observed a discreet and irregular activity on the first third, quiescence on the second third, transition on day 20 and intense and regular activity right before parturition. The oxytocin provoked uterine activity excitation by regular and intense contractions induction, revealing a similar profile obtained on day 21 of pregnancy. Results analysis demonstrated that uterus exhibits distinct contraction profile on each stage of pregnancy, as well as an evolution of contractile peristalsis aiming the development and fetus expelling. This work supply a new tool to contribute with new pathologies, hormones and drugs studies that modifies normal uterine contractility during gestation.
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Palavras-chave
contração uterina, útero, prenhez, ocitocina, biosusceptometria de corrente alternada, ratas, uterine contraction, uterus, pregnancy, oxytocin, alternate current biosusceptometry, rats