Expression and Hormonal Regulation of IL-11Rα in Canine Uterus During Early Pregnancy

Contents Embryo implantation is critical for the successful establishment of pregnancy. Interleukin-11 (IL-11) is essential for adequate decidualization in the mouse and human via binding to the specific IL-11 receptor alpha (IL-11R alpha). But the expression and regulation of IL-11 and IL-11R alpha in the canine endometrium remain unknown. The aim of this study was to investigate the differential expression of IL-11R alpha in canine uterus during early pregnancy and its regulation under different conditions by in situ hybridization. Interleukin-11R alpha mRNA was mainly localized in glandular epithelium in canine uterus. There was a low level of IL-11R alpha expression in the glandular epithelium on days 6, 12 and 17 of pregnancy. On day 20 of pregnancy when embryo implanted, IL-11R alpha mRNA was highly expressed in the glandular epithelium surrounding the embryo, but not in the luminal epithelium and stroma. On day 23 of pregnancy, the expression of IL-11R alpha mRNA maintained a constant level compared with the expression of day 20 and increased on day 28 of pregnancy. During the oestrous cycle, a high level of IL-11R alpha mRNA expression was seen in the oestrous uterus. Progesterone slightly induced the expression of IL-11R alpha mRNA in the ovariectomized canine uterus. These results suggest that IL-11R alpha expression is closely related to canine implantation and up-regulated by progesterone.