The role of adiponectin in placental development of diabetic rats

The Role of Adiponectin in Placental Development of Diabetic Rats ABSTRACT Placenta is an organ which acts as a barrier between maternal and fetal circulation during pregnancy and plays an important role in fetal development and growth. A healthy pregnancy is closely associated with normal placental development. Many physiological, immunological and metabolic adaptations are necessary for healthy placental/fetal development and maternal health. Placental development is one of the important criteria during pregnancy. Inadequate placental development may cause clinical complications such as intrauterine growth retardation, preeclampsia and diabetes. There is limited data about placental expression of adiponectin, which has anti-diabetic effects. In this study, relationship between adiponectin and placental development was studied in normal and streptozotocine (STZ) induced diabetic rats. Diabetic rat placentas were bigger than control placentas at gestational day 18 and 20 and diabetic embryos were smaller than control group at gestational day 14, 18 and 20. Results were statistically significant. Adiponectin and its receptors AdipoR1 and AdipoR2 expression were eveluated at mRNA and protein level. Adiponectin expression was significantly decreased at gestational day 16, 18 and 20 in diabetic group placentas. Maternal serum adiponectin levels were also eveluated and a significant decrease was observed in diabetic group blood sera. AdipoR1 expression was similiar between groups, on the other hand AdipoR2 expression was significantly decresed at gestational day 14, 18 and 20 in diabetic group placentas. In order to explain the effects of Adiponectin on placental development and in diabetic conditions in detail, PPARalpha, PPARgamma, RXRalpha (play roles in Adiponectin mechanisms) and p38 MAPK expression (play roles in PPAR signalization) levels were investigated. According to our results, pregnancy and diabetes is associated with adiponectin. A decrease in adiponectin level was determined in diabetes towards term. Depending on the decresase of adiponectin level, it was observed that PPARalpha, PPARgamma, RXRalpha (downstream molecules of adiponectin) expression levels were also decreased. Besides, a significant increase was oberved in p38 MAPK phosphorylation. In conclusion, we are of opinion that adiponection has an inportant role in placental development abnormalities in diabetic conditions. Key Words: Diabetes, Placenta, Adiponectin, AdipoR1, AdipoR2, PPARalpha,PPARγ, RXRalpha, p38 MAPK