Abstract

P 159

Long-term stabilization of regenerating adult retinal ganglion cells

Carolin Chiwitt1, Tobias Stupp1, Johannes Seeger2, Solon Thanos1
1Abteilung für Experimentelle Ophthalmologie, Universitätsklinikum Münster, Münster; 2Veterinär-Anatomisches Institut der Universität Leipzig, Leipzig

Objective
Adult retinal ganglion cells can regenerate their cut axons within peripheral nerve grafts used to “bypass” the distal optic nerve stump. We examined the longterm stabilization of these ganglion cells by guiding their regenerating axons into different termination areas.
Methods
The optic nerve of adult rats was completely cut intraorbitally and its ocular stump was connected with different visual target areas (cortex, midbrain) or with non-visual areas (e.g. muscle). Further controls were groups with only cut without graft and blind ending grafts. The function of the retina was regularly examined with ERG. The pupillary constriction on light illumination was also tested regularly, in order to assess potential functional restauration of the visual pathway. At 1, 6 and 9 months postsurgery, regenerating or only axotomized ganglion cells were retrogradely labelled with 4-Di-10-ASP and quantified morphometrically. Further, immunohistochemical and anterograde staining was applied.
Results
Regenerating ganglion cells remain stable up to 9 months after grafting at the optic nerve. There are quantitatively and morphometrically assessable differences between the experimental groups and the controls, with reconnected cells to become best type-specifically stabilized. Also electrophysiologically and pupillographically eyes with reconnected optic nerves show best functional outcome.
Conclusions
Adult ganglion cells of the rat can be reconnected with visual centres using a peripheral nerve “bypass”. This reconnection stabilizes the cells at morphological and functional levels for a long time.

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