| Research Abstract |
To elucidate functions of chondroitin sulfate proteoglycans (CSPGs) derived from the rat brain, we investigated the effects of brain CSPGs on proliferation and/or neurite outgrowth of PC12D cells and neurons of the dorsal root ganglia (DRG) and their immunocytochemical localization in rat embryo. Brain-type CSPGs prevented increases in the number of PC12D cells by blocking the cell cycle at the G2 phase and neurite elongation from PC12D cells, DRG explants and DRG neurons. DRG was formed at around embryonic day 12.5 (E12.5) and elongated their axons toward the neural tube at around E13.5. Neurocan, one of major brain CSPGs, was located at the boundary cap, apart from sites where the afferent axons from the DRG seemed to reach the neural tube, and the roof plate, a glial barrier in axon elongation, of the spinal cord at E13.5. Neurocan has been detected around the boundary cap at E12.5 when the DRG does not elongate their axons yet. Thus, neurocan may function as a barrier molecule in axon elongation from the DRG.Another CSPG,6B4 proteoglycanlike immunoreactivity, was found at several ganglions in the peripheral nervous system (PNS), when their neurons were still proliferating. Since its antibody prevent the inhibition of proliferation of PC12D cells by 6B4 proteoglycans, this proteoglycan may influence the cell proliferation in PNS.
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