Regulatory Changes of N-Acetylgalactosamine Terminal Sugar in Early Mouse Embryonic Paraxial Mesenchyme

Objective: the development of vertebrae is a complex phenomenon that is correlatedwith distinct morphological and biochemical alterations in the paraxial mesenchyme and glycoconjugates. the purpose of this study is to investigate the glycosylation pattern in paraxial mesenchyme-forming vertebrae by using the lectin histochemical technique.materials and methods: in this descriptive-analytic study, b4g fixed paraffin sections of9 to 15 day balb/c mouse embryos were processed for histochemical studies using seven different hrp-labelled lectins: glycin max (sba), maclura pomifera (mpa), wistaria flori- bunda (wfa), vicia villosa (vva) which all of them are specific for n-acetylgalactosamine (galnac), ulex europius (uea1, binds to ?-l-fucose), wheat germ agglutinin (wga, binds to sialic acid), and griffonia simplicifolia (gsa1-b4, binds to galactose terminal sugars). the sections were observed separately by three examiners who were blinded to the lec- tins. grading was done according to the intensity of the tested lectins’ reactions with the specimen, from negative (-) to severe (+++). data was analysed with spss software (ver- sion 11.5) and the non-parametric kruskal wallis test; p < 0.05 was considered significant.results: our findings showed that among the tested lectins, only galnac residue sensi- tive lectins showed regulated changes in paraxial mesenchyme. reactions of wfa and mpa lectins with paraxial mesenchyme were severe on gd9. reactions of wfa contin- ued to gd15 constantly, while mpa reactions continued strongly to gd12, significantly decreased thereafter (p < 0.001), and then disappeared. vva and sba bindings initiated weakly on gd10 and continued to gd12 without changing. these reactions increased significantly (p < 0.001) thereafter, became severe to gd14, and later disappeared. the other tested lectins did not reveal regulated changes.conclusion: according to these findings it can be concluded that only the galnac termi- nal sugar showed temporally regulated changes during the early embryonic development of vertebrae in mice. therefore it most likely plays a key role (s) in the development of ver- tebrae, especially in the conversion of mesenchymal cells into chondroblasts. the other tested terminal sugars may have no role in this phenomenon.