Purpose:
The goal of this study is to ascertain the functional impact of RPE debridement. We have investigated the time-dependent correlation between histopathological appearance and mfERG results, after RPE removal in an animal model.
Methods:
All experiment was carried out in accordance with the ARVO Statement on the use of animals in ophthalmic and vision research, and approved by the Danish Animal Experiment Inspectorate. 10 female domestic pigs were anaesthetised, endotracheally intubated and artificially ventilated. Access to the subretinal space was achieved by a central and posterior three-port vitrectomy followed by fluid injection into the subretinal space causing a retinal detachment bleb. Hereafter was the RPE debrided gently by brushing Bruch's membrane with a soft-tip silicone catheter. The impact of the RPE debridement was evaluated immediately after surgery and after two and six weeks by; 1) MfERG (VERIS Science 5.0.1) (first examination was performed at baseline, none immediately after surgery), 2) fundus photographs, 3) fluorescein angiograms and 4) histopathological examination.
Results:
The mean P1 amplitude, calculated with a one-way ANOVA, was at baseline 1,995 mV/dg2, it decreased to 1,278 mV/dg2 one week after surgery and 1,388 mV/dg2 two weeks after surgery. Six weeks after surgery it had increased to 2,169 mV/dg2 .Multivariate analysis for the three endpoints showed no significant difference between one and two weeks after surgery. The mfERG P1 amplitude one and two weeks after surgery is significantly decreased compared to baseline and six weeks after surgery. The mean P1 amplitude at six weeks is not significantly different from baseline.
Conclusions:
This is the first study to show that regeneration of RPE, in an animal model of RPE debridement, restores the retinal function. In our porcine model, when RPE migrates to the debrided area, the mfERG normalizes. Thus, the function of the photoreceptors in the healed area is restored.
Keywords: retinal pigment epithelium • electroretinography: clinical • regeneration