Abstract
Purpose :
Changes in the corneal barrier function can be shown by measuring the corneal bioimpedance. We evaluated if we were able to charactericise the damage produced in an experimental model of anterior surface inflammation (ASI) using a tetrapolar impedance meter .
Methods :
ASI was produced in 14 female New Zealand white rabbits by two different methods. In the first one (n=4) 40ul of 3% croton oil diluted in 2-ethoxyethanol was administered into the fornix of one of the eyes from each animal while the vehicle was administered into the other one. In the second one (n=10) 20ul of 3% croton oil diluted in dimethyl sulfoxide (DMSO) were administered into the fornix of one of the eyes from each animal while the vehicle was administered into the other one. Bioimpedance measures, mucous secretion (MS), chemosis (CH), neovascularization (NV) and corneal staining (CS) were assessed at each time point evaluation (baseline, 6, 24, 48 and 148 hours after exposure). Corneal tissue was extracted at the endpoint, evaluated by light microscopy, and inmunostained for ZO-1 and ZO-2.
Results :
In the first group we show that MS, CH and CS were present in the 6, 24 and 48 hours evaluations in 3/4 of the cases while only MS and CS were present in the remaining case after 6 and 24 hours. In the second group we show MS in every animal after 6 hours and CH in 90% of the cases after 6 hours and 80% after 24 hours, CS is not present at any time point of the evaluation. Bioimpedance measures show low impedance values after 6 and 24 hours in the first group while there were no differences with the basal values at other times. In the second group higher impedance values were observed 6 and 24 hours after the administration in 70% of the cases while there were no differences at anyother time point.
Conclusions :
We had been able to reproduce a short time animal model of ASI and measure its bioimpedance at different time points. The combination of croton oil 3% in DMSO is the best way of the two methods to study the effect of inflammation over the ocular surface because it do not damage corneal epithelium integrity, even though it produces shorter time effects. The bioimpedance measures reflect damage in the corneal barrier function at the same times that corneal staining is observed.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.