Purchase this article with an account.
Y. Duan, J. Thurston, Jr., B. Watson, E. Hernandez, R. Fern, J. L. Goldberg; Retinal Ganglion Cell Survival and Optic Nerve Glial Response After Rat Optic Nerve Ischemic Injury. Invest. Ophthalmol. Vis. Sci. 2007;48(13):644.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Why do neurons in the mature central nervous system (CNS) die after injury? For example, white matter ischemia leads to axon injury and then in most cases to retrograde death of CNS neurons. Recent evidence using an axotomy approach suggests that retinal ganglion cells die after axon injury for two reasons: they are cut off from target-derived trophic signals, and they lose responsiveness to such signals. Here we ask whether we can generate a clinically relevant model of ischemic optic neuropathy to study the mechanism underlying retinal ganglion cell (RGC) death.
We used the rat retina and optic nerve as a model system for CNS neurons and their axonal, white matter pathways, respectively. Using a photothrombotic model, we established an optic nerve ischemia model and studied the early changes associated with RGC ischemic axon injuries. Black ink perfusion was used to investigate the effect of photothrombotic treatment on retinal perfusion; electron microscopy and immunohistochemistry were used to investigate the responses of optic nerve glial cells, and retrograde labeling of RGCs using fluorogold was used to quantify the survival of RGCs after optic nerve injury.
The photothrombotic procedure did not compromise the blood supply to the retina, which makes this model suitable for studying white matter stroke. About 50% of RGCs survived 35 days after ischemic injury compared to 2% after optic nerve axotomy. In the optic nerve, we found that 50% of RGC axons were damaged 2 days after ischemic injury and microglial cells and other glial cells were activated at the site of the lesion.
Ischemic axon injury leads to neuronal death in a time dependent manner, associated with specific patterns of glial activation. Future studies are directed at elucidating the signaling pathways activated after axonal ischemic injury and characterizing the mechanisms leading to cell death using this model. Our long term goal is to provide insights into and possibly therapies for neuronal death after stroke.
This PDF is available to Subscribers Only