[ role of glycoconjugates in development of floor plate during early morphogenesis in mouse embryo]

ABSTRACT

The floor plate is a small group of cells located at the ventral midline of neural tube. During early neurogenesis, the floor plate plays critical role [s] in differentiation of ventral portion of neural tube. The purpose of this study was to determine the distribution of glycoconjugates in floor plate as well as underlying mesoderm [notochord] and their inductive activities in mouse embryos. Formalin fixed sections embedded in paraffin from 10 to 14 days old Balb/C mouse embryos were processed for histochemical studies by using five deferent horseradish peroxidase [HRP] labelled lectins including; Glycin max [SBA] specific for Gal and GalNac terminal sugar, Vicia Villosa [VVA] and Arachis hypogaea peanut] for GalNac, Ulex europeus [UEA-I] and Lotus tetragonolobus [LTA] for a- L-fucose. Our results showed that SBA sensitive glycoconjugates react and change in floor plate, notochordal cells and surrounding extracellular matrix and these changes were significant [P<0.05]. Extensive differences between GalNac sensitive lectins were observed during motoneuron differentiation. There was no reaction with other tested GalNac lectins. Furthermore we observed significant changes [P<0.05] in fucose glycoconjugates during notochordal development. The results suggest that the timing and distribution of SBA sensitive glycoconjugates may play a key role [s] in interactions and subsequent formation of adjacent tissues such as floor plate and notochord during critical period of morphogenesis. Our finding also showed that glycoconjugates with fucose terminal sugar might play a role [s] in notochordal development but probably have no function on floor plate development