Histomorphometerical effects of retinoic acid on red cells in rat's embryo

All–trans retinoic acid (ATRA) has beneficial and teratogenicity effects when used in a variety conditions. The objectives of this study were to determine the effects of ATRA on the red blood cells (RBC) and platelets in rat's embryo. In this study Wistar rats were used. They were maintained on laboratory chow and tap water provided ad libitum. Adult virgin females (n = 10) were mated overnight with males of the same stock. A vaginal plug and smear observed, indicated day 0 of pregnancy. Single dose of 100 mg/kg of ATRA suspended in alcohol; corn oil (1:9) mixture and was given by oral intubations on the morning of gestation day (GD) 10 to experimental group. The control group was vehicle treated. The fetuses blood (controls and ATRA treated each, n= 23) were obtained directly from heart, as placental and mother circulation was continued and subsequently processed for staining (Gimsa) and followed by counting. The fetuse's blood cells were studied by light microscope and eyepiece (x40 for count, 100 for diameter. The number of RBC and also and platelets were significantly lower than those of control group (P<0.0001, P<0.04, respectively). There was no significant relationship between diameter of RBC in treated and control groups. The present data showed that ATRA may has negative effects on proliferation and maturation of erythroid cell and platelet progenitors, without having any deleterious effects on the dime nation of cells, probably via events involving activation or suppression of specific genes.