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 glycoconjuga te residues were detected in the cytoplasm of some antimesometrial and mesometrial decidual cells with lectins from Canavalia ensiformis (Co n A), Lens culinaris (LcH), Pisum sativum (PSA), Griffonia 'simplicifo lia 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 gl ycoconjugate residues detected may be related to extracelluar matrix p roduced by decidual cells. Reactivity with PHA-E, demonstrating comple x carbohydrates, was most intense in the mesometrial decidua closest t o the trophoblastic giant cells and may demonstrate glycoconjugates in volved in maintaining integrity at this maternotrophoblast interface. Lectins derived from Helix pomatia (P-IPA), Vicia villosa (WA), Glycin e max (SEA) and Arachis hypogaea (PNA) reacted only with occasional sm all cells in antimesometrial or mesometrial decidua, probably demonstr ating alpha and/or beta-linked N-acetylgalactosamine residues on lymph ocytes or monocytes. The glycoprotein granules of granulated metrial g land (GMC) cells in the decidua basalis and the metrial gland reacted strongly with WGA, MPA and PHA-L demonstrating complex carbohydrates i ncluding sialic acid residues and tri/tetra-antennary, nonbisected N-l inked glycans. GMG cell cytoplasm reacted diffusely with Con A, LcH, P SA, WGA, PHA-E and PHA-L. In some GMG cells reactivity with WGA was ap parently localised to the Golgi region indicating involvement in granu le formation. Pericellular reactivity of some GMG cells with WGA may r elate to migratory activity. The lectin reactivity of fibroblast-like stromal cells in the metrial gland was similar to that of the extracel luar matrix and it is likely that many matrix molecules are produced b y the stromal cells. A range of lectins (Con A, LcH, PSA, GS-II GS-I a nd 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 deriv ed from Dolichos biflorus (DBA), Bauhinia purpurea (BPA), Lotus tetrag onolobus (LTA) and Ulex europaeus-l (UEA-I) did not react with decidua l and metrial gland regions. Lectin binding profile studies can provid e further information on the events occurring in the uterus in pregnan cy: investigations at the ultrastructural level are required to resolv e further intra and extracellular changes.