Estudo Longitudinal, Bioquímico e Histoquímico, de Placentas de Ratas Diabéticas: Relação com a Macrossomia e o Retardo de Crescimento Intra-uterino
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Data
1999-03-01
Autores
Calderon, Iracema de Mattos Paranhos [UNESP]
Rudge, Marilza Vieira Cunha [UNESP]
Ramos, Maria Delgi [UNESP]
Peraçoli, José Carlos [UNESP]
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Editor
Federação Brasileira das Sociedades de Ginecologia e Obstetrícia
Resumo
Objetivo: o estudo longitudinal, entre o 18º e o 21º dias de prenhez, das alterações bioquímicas e histoquímicas das placentas de ratas diabéticas, cujos fetos tiveram macrossomia e retardo de crescimento intra-uterino (CIUR). Material e Método: usando modelo experimental em ratas, foram estudados 3 grupos: controle, diabete moderado e grave. A prenhez foi resolvida por cesárea no 18º ou no 21º dia. Compararam-se as glicemias materna e fetal; a incidência de recém-nascidos (RN) de peso pequeno (PIP), adequado (AIP) e grande (GIP) para tempo de prenhez; peso, índice e conteúdo de DNA, RNA e proteínas placentários e quantidade de glicogênio na superfície de trocas materno-fetais. Resultados: no diabete moderado houve maior proporção de RN-GIP com placentas ricas em DNA e diminuição progressiva de glicogênio em suas membranas no final da prenhez. No diabete grave houve predomínio de RN-GIP e as placentas exibiram menor conteúdo de DNA, síntese aumentada de RNA e tendência a maior produção protéica, com manutenção dos depósitos de glicogênio. Conclusões: concluiu-se que, entre o 18º e o 21º dias, os desvios do crescimento fetal no diabete materno, moderado e grave relacionam-se a alterações placentárias distintas. No moderado há apenas hiperplasia celular, com desaparecimento do glicogênio no final da prenhez. No grave, a superfície de trocas materno-fetais é mais espessada e, além de hiperplasia, há hipertrofia das células, com manutenção dos estoques placentários de glicogênio.
Purpose: placental alterations were evaluated in macrosomatia and fetal growth retardation in pregnancy complicated by diabetes. Three groups of rats, used as experimental models, were studied: control, moderate and severe diabetes. Material and Method: cesarian sections were carried out on the 18th or 21st day of pregnancy. Maternal and fetal glycemia, newborn weight, placental weight, relationship between placental and fetal weight, DNA, RNA and protein contents and the glycogen deposited on placental membranes were analyzed. Results: there was a higher number of macrosomic newborns in the moderate diabetes group, whose placentas were rich in DNA with progressive decrease of glycogen in their membranes towards the end of pregnancy. There was a predominance of small for date newborns in the severe diabetes group. Their placentas showed a small DNA proportion, an increase in RNA synthesis and a tendency to higher protein production, with no change in the glycogen deposit. Conclusions: we conclude that fetal growth deviation in moderate and severe maternal diabetes between the 18th and 21st days of pregnancy is related to several placental alterations. In the moderate form there were only cellular hyperplasia and disappearance of placental glycogen at the end of pregnancy. In the severe diabetes group there was thickening of maternal-fetal membranes during this period. There was cellular hyperplasia and hypertrophy associated with the maintenance of glycogen reserves in the placental membranes.
Purpose: placental alterations were evaluated in macrosomatia and fetal growth retardation in pregnancy complicated by diabetes. Three groups of rats, used as experimental models, were studied: control, moderate and severe diabetes. Material and Method: cesarian sections were carried out on the 18th or 21st day of pregnancy. Maternal and fetal glycemia, newborn weight, placental weight, relationship between placental and fetal weight, DNA, RNA and protein contents and the glycogen deposited on placental membranes were analyzed. Results: there was a higher number of macrosomic newborns in the moderate diabetes group, whose placentas were rich in DNA with progressive decrease of glycogen in their membranes towards the end of pregnancy. There was a predominance of small for date newborns in the severe diabetes group. Their placentas showed a small DNA proportion, an increase in RNA synthesis and a tendency to higher protein production, with no change in the glycogen deposit. Conclusions: we conclude that fetal growth deviation in moderate and severe maternal diabetes between the 18th and 21st days of pregnancy is related to several placental alterations. In the moderate form there were only cellular hyperplasia and disappearance of placental glycogen at the end of pregnancy. In the severe diabetes group there was thickening of maternal-fetal membranes during this period. There was cellular hyperplasia and hypertrophy associated with the maintenance of glycogen reserves in the placental membranes.
Descrição
Palavras-chave
Diabete e gravidez, Macrossomia -- CIUR. Placenta, Diabetic and pregnancy, Macrosomatia -- IUGR. Placental
Como citar
Revista Brasileira de Ginecologia e Obstetrícia. Federação Brasileira das Sociedades de Ginecologia e Obstetrícia, v. 21, n. 2, p. 91-98, 1999.