Abstract
Purpose :
Ferrets are well-developed experimental animals with small bodies. They are commonly used in visual system research, but there are few reports using ferrets about the research for ocular disease such as glaucoma. We consider that ferrets could be suitable novel experimental animals for ophthalmological research. In this study, we investigated the IOP (intraocular pressure) lowering reactions to anti-glaucomatous drugs, latanoprost (LAT) which acts on uveoscleral outflow, or ripasdil (RIP) which acts on trabecular outflow, and the histological morphology of iridocorneal angle associated with IOP regulation, using ferrets.
Methods :
15-16 week-old normal male ferrets were gradually acclimated to housing, handling, and IOP measurement over a week. 0.005% LAT or 0.4% RIP was topically administrated to one eye in ferrets. IOP was measured using rebound tonometer without anesthesia before, and at 2, 4, 6, 8, and 10 h after administration. For morphological investigation, hematoxylin-eosin stained sections of the iridocorneal angle of euthanized ferrets, rats, and monkeys were prepared.
Results :
Both anti-glaucomatous drugs reduced IOP in normal ferrets, and the effect of LAT was superior to that of RIP on lowering IOP. LAT significantly began reducing the IOP at 2 h after administration and the effect tended to last until 10 h. Moreover, initial hypertensive reaction following LAT administration was not observed in ferrets.
In morphological investigation, ferrets were similar to rodents in the structure of lamellar trabecular meshwork, while were more similar to primates than rodents in the location of Schlemm’s canal. The uveoscleral pathway would be observed, and ciliary muscle of ferrets was higher developed than that of rodents.
Conclusions :
On IOP lowering reactions to anti-glaucomatous drugs and the histological morphology of iridocorneal angle, ferrets were more similar to human than rodents. The results of the IOP lowering by LAT and RIP indicated the presence of both trabecular and uveoscleral outflow in ferrets. These suggest that ferrets might be useful for glaucoma research such as mechanistic analysis and screening for ocular hypotensive candidates.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.