Inhibition of implantation by intraluminal administration of concanavalin A in mice

Abstract

Important characteristics of endometrial implantation sites are the changes of polarity and molecular composition of the cellular surface. For this reason the masking of surface carbohydrates could lead to an inhibition of the recognition by the blastocyst of the endometrial implantation site. Considering the impact of lectins on carbohydrates, we decided to utilize the intraluminal administration (5 μl) of different concentrations of concanavalin A (15–60 μg) in pregnant female mice in the preimplantation phase. An inhibition of 100% of implantation was obtained with concentrations of 30 and 60 μg of the lectin administered on days 3 and 4 of the pregnancy (P < 0.001). Less important effects were observed on administering 15 or 20 μg of the lectin (73 and 87% of inhibition) and on utilizing the different doses on days 1 and 2 of the pregnancy. Thus, we conclude that the egg must recognize certain molecules of the endometrial surface (α-D-mannopyranose and α-D-glucopyranose) in order to implant and that the masking of these sites potentially constitutes a new contraceptive approach.