advertisement
Abstract #26096 Published in IGR 12-2
Time-dependent effects of focal retinal ischemia on axonal cytoskeleton proteins
Balaratnasingam C; Morgan WH; Bass L; Kang M; Cringle SJ; Yu DYInvestigative Ophthalmology and Visual Science 2010; 51: 3019-3028
PURPOSE: To examine the time-dependent effects of focal axonal ischemia on the retinal ganglion cell (RGC) cytoskeleton. METHODS: Eight pigs were used. Small retinal arteriolar branches were occluded by argon laser to induce focal ischemic insults that were maintained for a period of 6 hours or 1 hour. Treated and untreated retinal segments were dissected from the eye after euthanatization. Each retinal segment followed the longitudinal projection of RGC axons from peripheral retina to the optic disc. Antibodies to phosphorylated neurofilament heavy, phosphorylation-independent neurofilament heavy (NFH), neurofilament light, neurofilament medium, microtubule, and microtubule-associated proteins were used to study the axonal cytoskeleton. Glial fibrillary acidic protein and TUNEL staining were also used to examine astrocyte and apoptotic changes, respectively. Comparisons were made between treated and untreated retinal segments. RESULTS: Cytoskeleton protein changes occurred within ischemic regions and also within retinal tissue on the disc side and peripheral side of the ischemic regions. NFH and microtubule proteins were the earliest cytoskeleton subunits that underwent change. Changes to all cytoskeleton proteins, apart from NFH, occurred in a time-dependent manner within regions of ischemia. In the time points studied, cytoskeleton changes occurred in the absence of detectable astrocyte changes and RGC apoptosis. CONCLUSIONS: An ischemic insult induces RGC cytoskeleton protein change, implying that the local environment plays an important role in modulating axonal structure and function. Cytoskeleton proteins are likely to be important pathogenic mediators of neuronal dysfunction in diseases such as glaucoma and retinal vascular disease.
Centre for Ophthalmology and Visual Science and the ARC Centre of Excellence in Vision Science, The University of Western Australia, Perth, Australia.
Classification:
5.3 Other (Part of: 5 Experimental glaucoma; animal models)
3.6 Cellular biology (Part of: 3 Laboratory methods)
6.11 Bloodflow measurements (Part of: 6 Clinical examination methods)
