Abstract
Purpose :
Dry eye syndrome, or keratoconjunctivitis sicca (KCS), affects millions of people worldwide. Complementary animal models of KCS including rodents, rabbits, and dogs were developed to evaluate new therapies. The utilization of environmental parameters was evaluated to assess and accelerate the KCS condition.
Methods :
CD-1 mice were housed under arid conditions (~20% humidity) in either a standard rodent cage or an airflow chamber (cage fitted modified airflow system) and administered 50µL of 1% atropine topically into both eyes every other day for 8 days (N=5/group). A control group (N=2) was housed under standard conditions. Tear production and corneal damage were assessed using modified Schirmer tear tests and fluorescein staining on Days 0, 3, 5, and 8.
Female New Zealand White rabbits (N=10) were housed at ~20% humidity with increased airflow and administered 50µL of 1% atropine topically into both eyes 3x daily for 43 days. Starting on Day 21, animals received 50µL of either RESTASIS® (N=5) or vehicle (N=5) topically into both eyes twice daily (BID). Tear production was assessed using Schirmer tear tests and fluorescein tear break-up tests once weekly.
Female Beagle dogs were housed at ~20% humidity with increased airflow and administered 50µL of either 1% atropine (N=5) or 0.4% benzalkonium chloride (BAC) (N=5) topically into both eyes 4x daily for the duration of the study. Upon confirmation of KCS, animals received 50 µL RESTASIS® (N=3/group) or vehicle (N=2/group) topically into both eyes BID. Tear production and corneal damage were assessed using Schirmer tear tests and fluorescein staining once weekly.
Results :
Topical ocular atropine or BAC with the addition of environmental conditions (increased airflow, decreased humidity) enhanced symptoms including reduced tear production, fluorescein staining, and/or faster tear film break-up in all tested animals. These symptoms were not observed in the untreated animals. Treatment with RESTASIS® was observed to increase tear production and slow tear film break-up compared to vehicle-treated groups.
Conclusions :
Environmental parameters can be used to enhance the KCS condition compared with the use of topical agents alone. This enables the development of sensitive preclinical models to test the efficacy of novel treatment therapies.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.