mRNA expression of PDGF-bb and its receptors at the porcine maternal-fetal interface. PDGF-bb (A, D), PDGFRα (B, E), and PDGFRβ (C, F) mRNA transcripts were quantified in non-pregnant endometrium and gd20 and gd50 endometrium and chorioallantoic membrane from healthy (HE, HCAM) and arresting (AE, ACAM) conceptus attachment sites. Transcript levels are relative to β-actin. ND= Not detected. Data was log transformed before analysis by ANOVA, p < 0.05 were considered significant. ACAM: arresting conceptus chorioallantoic membrane; HCAM: healthy conceptus chorioallantoic membrane; HE; healthy endometrium; AE: arresting endometrium.