Immunohistochemical localization of chondroitin sulfate proteoglycans in the developing rat hindbrain

Abstract

Our biochemical analysis has shown the occurrence of chondroitin sulfate proteoglycans (CSPGs) in the hindbrain of rat embryos. To localize their expression in the embryos, immunohistochemistry was applied on cryosections of E11.5, E12.5 and E13.5 embryos. Epitopes of CS were detectable in the extra/peri-cellular environment of the neuroepithelium at E11.5 and E12.5. Signals were very weak by E13.5. The results were confirmed by the disappearance of signals following chondroitinase treatment of the sections. Versican-positive signals were pericellular in all three stages. The immunoreactivity was strong towards the ventricular region at E11.5. The signals declined by E12.5 and strong immunoreactivity was found towards the pial surfaces. Neurocan-positive signals appeared to be intracellular and concentrated in a cell layer lining the pial side of the neural tube as early as E12.5. Phosphacan-positive signals were not detectable in all three stages. As hyaluronan binds CSPGs, experiments were also performed to localize hyaluronan in the embryos. The hyaluronan staining pattern resembled that of versican in all three stages, suggesting interaction between versican and hyaluronan in the development of the embryonic hindbrain.