Septa And Valve Morphogenesis In Mouse Embryo Heart: A Lectin Pna Based Study

Lectin peanut aglutinin histochemistry was used to elucidate histogenesis of septa and valves in mouse heart morphogenesis. Soon after the proliferation of mesenchyme cells in endocardial cushions, lectin peanut aglutinin was found to recognise a glycoprotein of about 65 kDa, which is part of a fibrous network present in the extracellular matrix of endocardial cushions. During a later stage of morphogenesis, both atrioventricular and spiral septa were positive to peanut aglutinin, while interatrial septa were not labelled. Ar the completion of morphogenesis, septa showed a marked decrease of peanut aglutinin positivity, in concomitance with extended fenestrations of the septal tissue; however, valve leaflets were still positive to the lectin. Thus, lectin peanut aglutinin appears to be a reliable marker of endocardial cushion-derived tissues during valvuloseptal morphogenesis.