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Abstract #70413 Published in IGR 18-2
Reversal of functional loss in a rat model of chronic intraocular pressure elevation
Liu HH; He Z; Nguyen CT; Vingrys AJ; Bui BVOphthalmic and Physiological Optics 2017; 37: 71-81
See also comment(s) by Benjamin J. Frankfort •
PURPOSE: This pilot study considered whether intraocular pressure (IOP) lowering could reverse ganglion cell dysfunction in a rat model of chronic ocular hypertension. METHODS: A circumlimbal suture was applied in one eye to induce ocular hypertension (n = 7) in Long-Evans rats. The contralateral eye served as an untreated control. After 8 weeks of IOP elevation the suture was removed to lower IOP for the remaining 7 weeks. Electroretinogram (ERG) and optical coherence tomography (OCT) were measured at baseline, 2, 4, 8, 12 and 15 weeks. Retinae were collected for histology at week 15. RESULTS: In sutured eyes, IOP was elevated by 7-11 mmHg above control eyes (12 ± 0.2 mmHg [standard error of the mean]). Eight weeks of chronic IOP elevation resulted in a reduction of the ganglion cell mediated positive Scotopic Threshold Response (pSTR, -25 ± 7% of baseline), as well as smaller photoreceptor (-7 ± 4%) and bipolar cell mediated responses (-6 ± 5%). After suture removal, IOP recovered to normal. By 15 weeks the a-wave (0 ± 6%), b-wave (-2 ± 6%) and pSTR had recovered back to baseline (from -25 ± 7% to -4 ± 6%). The retinal nerve fiber layer was thinned by -9 ± 3% at week 8 and showed no further decline at week 15 (-10 ± 2%). Cell numbers in the ganglion cell layer were similar between suture removal and control eyes at week 15 (3543 ± 478 vs 4057 ± 476 cells mm(-2) ). CONCLUSIONS: The circumlimbal suture model might be a useful platform to study the reversibility of neuronal dysfunction from chronic IOP challenge.
Department of Optometry & Vision Sciences, University of Melbourne, Parkville, Australia.
Full articleClassification:
5.1 Rodent (Part of: 5 Experimental glaucoma; animal models)
11.8 Neuroprotection (Part of: 11 Medical treatment)
