Current eye research

Chronic ocular hypertensive rat model using microbead injection: comparison of polyurethane, polymethylmethacrylate, silica and polystyene microbeads.

PMID 24588104


To establish and assess an ocular hypertensive rat model using intracameral injection with various microbeads of different sizes and materials. Chronic elevation of intraocular pressure (IOP) was induced by the injection of various microbeads into the anterior chamber of Sprague-Dawley rat eyes. We compared the IOPs induced by the injection of different microbeads [7- and 17-µm polyurethane (PU), 7- and 15-µm polymethylmethacrylate (PMMA), 13-µm silica, and 15-µm polystyrene (PS)] and selected the appropriate microbeads for a chronic ocular hypertensive model in terms of IOP elevation and adverse events. IOP changes were observed for 4 weeks after microbead injections. Axonal degeneration was assessed with transmission electron microscopic photographs and RGC loss was assessed with retrograde labeling. Seventy-eight rats were included. Three days after a single injection of microbeads, IOPs were increased by 24.0% by 7-µm PU microbeads, 101.8% by 17-µm PU microbeads, 56.6% by 7-µm PMMA microbeads, 22.0% by 15-µm PMMA microbeads, 153.0% by 13-µm silica microbeads, and 34.7% by 15-µm PS microbeads. 17-µm PU microbeads produced constant IOP elevation with good reproducibility (standard deviation of <6.5 mmHg). Silica injected eyes showed severe inflammation. Sustained IOP elevation by two injections of 17-µm PU microbeads resulted in a 42% axon loss and 36.5% RGC loss (p < 0.05, Mann-Whitney U test). PU microbead injections offer an applicable and versatile model for a chronic ocular hypertensive model in rats. Among several biomaterials, PU microbeads produced a more stable IOP elevation without adverse events.

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Proparacaine hydrochloride, analytical standard
C16H26N2O3 · HCl