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Abstract #10246 Published in IGR 6-1
Neuro-glial interactions in the adult rat retina after reaxotomy of ganglion cells: examination of neuron survival and phagocytic microglia using fluorescent tracers
Schuetz E; Thanos SBrain Research Bulletin 2004; 62: 391-396
Retinal ganglion cells (RGCs) regenerating through peripheral nerve grafts show enhanced survival after further axonal injury for at least four weeks. The authors examined the survival of the neurons and their microglial phagocytosis in dependence of the site of reaxotomy. The optic nerve of adult rats was transected at different distances from the eye cup and replaced with an autologous piece of sciatic nerve. After 14 days of axonal growth, the regenerated neurites were reaxotomized either within the remaining optic stump or within the graft, and their cell bodies were labeled retrogradely. Reaxotomy of regenerated ganglion cells within the remaining optic nerve resulted in reduced (but not significant) ganglion cell survival and significant microglial phagocytosis, in contrast to reaxotomy within the peripheral nerve graft. Furthermore, phagocytosis-dependent labeling using two different fluorescent tracers revealed that the same microglial cell can phagocytose further dying ganglion cells within 14 days of the first activation. These results suggest that the intrasciatic segments of axons receive some trophic support which is retrogradely transported and required to limit the microglial activation. The microglial capability to phagocytose dying neurons several fold emphasizes their function in permanent scavenging within the retina.
Dr. S. Thanos, Department of Experimental Ophthalmology, University Eye Hospital Munster, Domagkstrasse 15, 48149 Munster, Germany
Classification:
2.13 Retina and retinal nerve fibre layer (Part of: 2 Anatomical structures in glaucoma)
