Analysis of the placental tissue transcriptome from normal and testosterone treated rat pregnancy

Elevated testosterone levels increase maternal blood pressure and decrease uterine blood flow in pregnancy, resulting in abnormal perinatal outcomes. The placenta is the key in understanding the pathophysiological processes associated with pregnancy. The current study is designed to characterize the genes essential for placental function to understand the mechanisms underlying normal and pathological gestation. Timed pregnant Sprague-Dawley rats (day 12 of gestation; copulation plug on day 1; Charles River, Wilmington, MA) were selected. After acclimatization, on gestational day (GD) 13, dams were randomly divided into 2 groups. Dams in the treatment group were subcutaneously injected with testosterone propionate (0.5 mg/Kg/day, n=12) for 5 days from GD 15–19. The control group received vehicle (sesame oil, n=12).The animals were housed in a room with a controlled temperature and a 12-hour light-dark cycle. During 8-10 am on days 20 of pregnancy, rats were anaesthetized with carbon dioxide, three placentas each from male and female fetuses in control and testosterone-treated rats were disected and total RNAs were isolated. The isolated RNA from each animal was used for the cRNA preparation. cRNA was prepared and fragmented as suggested by Affymetrix technical manual, and simultaneously hybridized to Affymetrix Rat Expression Array 230 2.0. The data were analyzed with R statistical package (version 2.8.1), GeneSpring GX - Agilent Technologies and Ingenuity pathway analysis .