Rat Model of Normotensive IOP

The measurement of intraocular pressure (IOP) in laboratory animals is a common endpoint in ocular toxicology studies. However, when IOP is the main endpoint of interest, it is important to ensure the selected test system is appropriate for use.

For our validation study, we compared Brown Norway and Wistar rats for IOP and their response to topical ocular treatment with Latanoprost® (Xalatan®), a commercially available Prostaglandin F2α Analogue known for its IOP lowering effect.

Intravitreal Hypertonic Saline Model of Hypertensive IOP in Rabbits

The intravitreal hypertonic saline model of hypertensive intraocular pressure (IOP) may be used for IOP-lowering therapeutic agents when there is a desire to characterize efficacy in a system with elevated IOP.

To validate this model, a 5% hypertonic saline is injected into the vitreous of New Zealand White rabbits to produce an osmotic imbalance resulting in water entry into the eye and subsequent elevation in IOP. The effect is rapid and substantial, with an ~100-150% increase in IOP within 30 minutes of hypertonic saline administration. The elevation in IOP normalizes naturally within approximately 3 hours, and animals can be re-challenged on a weekly basis.

chart of intraocular pressure (IOP) values for rabbit eyes intravitreally injected with various treatments