Yasushi Wada1,2, Tomomi Higashide1, Kimikazu Sakaguchi1, Atsushi Nagata2, Kazuyuki Hirooka3, Kazuhisa Sugiyama1. 1. Department of Ophthalmology, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan. 2. Ophthalmology, National Hospital Organization Kanazawa Medical Center, Kanazawa, Japan. 3. Ophthalmology and Visual Science, Graduate School of Biomedical Science, Hiroshima University, Hiroshima, Japan.
Abstract
PURPOSE: To investigate the optic nerve head (ONH) blood flow, retinal vessel diameters, and retinal ganglion cell (RGC) loss after systemic administration of aldosterone in rats. METHODS: Aldosterone (80 µg/kg/day) or vehicle was administered using an osmotic minipump in Brown Norway rats. The mean blur rate in the vessel (MV) and tissue (MT) regions and retinal vessel diameters in the ONH were measured by laser speckle flowgraphy before and 1, 2, and 4 weeks after administration of aldosterone or vehicle. Intraocular pressure (IOP), blood pressure, and heart rate were recorded. The retrogradely labeled RGCs were counted in the retinal flatmounts prepared 5 weeks after treatment. RESULTS: The MV and MT in the aldosterone group significantly decreased at 2 and 4 weeks (MV: 2 weeks, p = 0.001, 4 weeks, p < 0.001; MT: 2 weeks, p = 0.02, 4 weeks, p = 0.03). The artery and vein diameters significantly decreased at 1, 2, and 4 weeks in the aldosterone group (all p < 0.001). The MV, MT, and vessel diameters remained unchanged in the vehicle group. Other parameters did not change over time in either group. RGC counts were significantly lower in the aldosterone group than in the vehicle group (p < 0.001). CONCLUSIONS: ONH blood flow decreased following retinal vessel constriction without changes in IOP or blood pressure in a possible rat model of RGC loss by systemic administration of aldosterone.
PURPOSE: To investigate the optic nerve head (ONH) blood flow, retinal vessel diameters, and retinal ganglion cell (RGC) loss after systemic administration of aldosterone in rats. METHODS: Aldosterone (80 µg/kg/day) or vehicle was administered using an osmotic minipump in Brown Norway rats. The mean blur rate in the vessel (MV) and tissue (MT) regions and retinal vessel diameters in the ONH were measured by laser speckle flowgraphy before and 1, 2, and 4 weeks after administration of aldosterone or vehicle. Intraocular pressure (IOP), blood pressure, and heart rate were recorded. The retrogradely labeled RGCs were counted in the retinal flatmounts prepared 5 weeks after treatment. RESULTS: The MV and MT in the aldosterone group significantly decreased at 2 and 4 weeks (MV: 2 weeks, p = 0.001, 4 weeks, p < 0.001; MT: 2 weeks, p = 0.02, 4 weeks, p = 0.03). The artery and vein diameters significantly decreased at 1, 2, and 4 weeks in the aldosterone group (all p < 0.001). The MV, MT, and vessel diameters remained unchanged in the vehicle group. Other parameters did not change over time in either group. RGC counts were significantly lower in the aldosterone group than in the vehicle group (p < 0.001). CONCLUSIONS: ONH blood flow decreased following retinal vessel constriction without changes in IOP or blood pressure in a possible rat model of RGC loss by systemic administration of aldosterone.