Abstract
Purpose :
Zebrafish have served as a robust model for studying human ocular abnormalities due to their similarities in eye development. There are many studies examining Zebrafish larvae to measure visual function with the electroretinogram (ERG), however there is limited research for adult zebrafish. Our goal in this study was to develop a reliable methodology of attaining ERG results in adult fish that is accurate and reproducible. We compared our ERG results to a behavior acuity test (OKR) to compare the results from the ERG to test the consistency of our testing setup.
Methods :
Zebrafish were maintained under standard conditions. The ERG set-up consisted of a 3D printed stand hold the fish in place and to support the stimulating LED, neutral density filters, and electrodes. A separate drip system provided an anesthetic solution between flash sequences. A bio amplifier sent the signals to a iDAQ data acquisition system that was connected to a PC. A silver electrode was placed across the fish cornea with appropriate reference electrodes. Flash paradigms and sequences were controlled using an ardruino microcontroller, connected to the same PC as the iDAQ. Because the initial goal was to capture photopic recordings to correlate with OKR data, fish were kept in their normal lighting for the ERG recordings. Flashes were generally done at 200ms durations, which elicited reproducible a and b-waves. OKR analysis was done as described previously. Correlations were made between ERG responses and calculated visual acuities.
Results :
We were able to identify peak amplitudes and latencies for both A and B waves that were consistent with previously published data and appropriate for the light stimuli provided. The results were consistent between fish and also in repeated measurements on the same animals. Interestingly a negative correlation was observed in the b-wave with fish acuity, even after accounting for age. The a-wave had a slight negative correlation but was not significant.
Conclusions :
Our set-up for full-field ERG produced repeatable and accurate measurements of visual function in adult zebrafish. The system is modular and easy to setup and allowed for an easy transition from ERG to OKR for additional visual testing. The ability to reliably test both retina function and assess overall visual acuity and other OKR parameters will enable robust studies of fish vision and the development of therapeutic interventions with the fish and an animal model for human vision.
This is a 2020 ARVO Annual Meeting abstract.