Lectin histochemistry of pregnant rat uterine tissues

Glycoconjugate residues were examined in the rat uterus at days 10, 12 and 15 of pregnancy using 17 biotinylated lectins with specificities for a variety of carbohydrate moieties. A wide variety of glycoconjugate residues were detected in the cytoplasm of some antimesometrial and mesometrial decidual cells with lectins from Canavalia ensiformis (Con A), Lens culinaris (LcH) culinaris (LcH), Pisum sativum (PSA), Griffonia simplicifolia II (GS-II), Triticum vulgaris (WGA), Griffonia simplicifolia I (GS-I), Maclura pomifera (MPA) and Phaseolus vulgaris (PHA-E and PHA-L). Reactivity with some of these lectins was also pericellular and the glycoconjugate residues detected may be related to extracelluar matrix produced by decidual cells. Reactivity with PHA-E, demonstrating complex carbohydrates, was most intense in the mesometrial decidua closest to the trophoblastic giant cells and may demonstrate glycoconjugates involved in maintaining integrity at this maternotrophoblast interface. Lectins derived from Helix pomatia (HPA), Vicia villosa (VVA), Glycine max (SBA) and Arachis hypogaea (PNA) reacted only with occasional small cells in antimesometrial or mesometrial decidua, probably demonstrating alpha and/ or beta-linked N-acetylgalactosamine residues on lymphocytes or monocytes. The glycoprotein granules of granulated metrial gland (GMG) cells in the decidua basalis and the metrial gland reacted strongly with WGA, MPA and PHA-L demonstrating complex carbohydrates including sialic acid residues and tri/tetra-antennary, nonbisected N-linked glycans. GMG cell cytoplasm reacted diffusely with Con A, LcH, PSA, WGA, PHA-E and PHA-L. In some GMG cells reactivity with WGA was apparently localised to the Golgi region indicating involvement in granule formation. Pericellular reactivity of some GMG cells with WGA may relate to migratory activity. The lectin reactivity of fibroblast-like stromal cells in the material gland was similar to that of the extracellular matrix and it is likely that many matrix molecules are produced by the stromal cells. A range of lectins (Con A, LcH, PSA, GS-II GS-I and PHA-L) reacted with some blood vessels in the metrial gland at day 12 of pregnancy: this may indicate activation changes associated with the transendothelial passage of GMG cells at this stage. Lectins derived from Dolichos biflorus (DBA), Bauhinia purpurea (BPA), Lotus tetragonolobus (LTA) and Ulex europaeus-I (UEA-I) did not react with decidual and metrial gland regions. Lectin binding profile studies can provide further information on the events occurring in the uterus in pregnancy: investigations at the ultrastructural level are required to resolve further intra and extracellular changes.