Intravitreal saline injection ameliorates laser-induced retinal damage in rats

PURPOSE: Injury to the central nervous system has been shown to trigger a physiologic response in the form of some degree of natural self-repair. This beneficial reaction may be boosted by appropriate preconditioning via a reversible injury to the retina. Here we report the ameliorative effect of intravitreal saline injection on laser-induced retinal damage. METHODS: Standard argon laser lesions (514 and 544 nm, 200 μm, 0.1 W, 0.05 seconds) were induced in the eyes of 36 Dark Agouti pigmented rats and immediately followed by injection of saline either intravitreally (5 μL) or intravenously (0.5 mL). Lesions were evaluated histologically and morphometrically after 3, 20, and 60 days. RESULTS: At all 3 time points, the eyes of rats injected intravitreally showed less laser-induced retinal cell loss (P < 0.05) and smaller lesion diameters (P < 0.05) than those of intravenously injected rats. CONCLUSION: Intravitreal saline injection evidently has a neuroprotective effect on the rat retina. The mechanism of action of this effect should be further elucidated and its clinical applicability tested.