Biochemical and Histochemical Longitudinal Analysis of Placentas of Diabetic Rats: Relationship with Macrosomatia and Intrauterine Growth Retardation - Revista Brasileira de Ginecologia e Obstetrícia

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.