The effect of adiponectin and its receptors in placental development of diabetic rats

Placenta development is an essential process for normal fetal growth and development, and healthy pregnancy maintenance. Inadequate placental development may cause clinical complications like diabetes, intrauterine growth retardation and preeclampsia. Due to limited data about placental expression of adiponectin, which has anti-diabetic effects, we studied the relationship between adiponectin and placental development in streptozotocin (STZ)-induced diabetic and normal rats. We also investigated Adiponectin receptors and the downstream adiponectin molecules like peroxisome proliferator-activated receptor (PPAR) α, PPARγ, retinoic acid receptor (RXR)α in the development of the diabetic placenta to explain the effects of Adiponectin in detail. Diabetic rat placentas were found to be heavier than control placentas at the 18th and 20th gestational days, while diabetic embryos were lighter than control group at the 14th, 18th and 20th days of gestation. Adiponectin protein level decreased in diabetic placenta towards term. Moreover, maternal serum adiponectin levels were found to be significantly decreased in diabetic group. Adiponectin receptor 1 (AdipoR1) mRNA expression levels were similar between groups, while Adiponectin receptor 2 (AdipoR2) mRNA expression was significantly decreased at the 14th, 18th and 20th days of gestation in diabetic placentas. Additionally, the mRNA and protein expression of PPARα, PPARγ, and RXRα were found to be decreased in diabetic placentas. These observations show that diabetes and pregnancy is associated with adiponectin levels. In conclusion, our data reveals that adiponectin plays a role in improvement of placental development in diabetic conditions, in the investigated animal species.