Alternative method in experimental ERG for retinal toxicity

We aimed to define a cost-effective and alternative method for experimental electroretinography (ERG) in rabbits. The trigger input port of data acquisition device was connected to output port of an unemployed EEG device. The exposure area of photic stimulator was firmly covered by Wratten neutral density filters with variable optical densities(ODs). Different optical transmissions were obtained by putting more than one filter over the other one. The illumination of the area at the level of rabbit eye was measured by a luminometer in photic stimulations. ERG was performed to the both eyes of three albino rabbits in scotopic and photopic conditions at the baseline. Intravitreal saline injections were performed in right eyes of the rabbits. ERG and ophthalmologic examination were repeated one week later. ERG responses were obtained by short-duration light stimuli with different strengths in scotopic (-2.69; -1.69; 0.00; 0.30; 0.69; 0.90; 1.10; 1.30; 1.69; 2.00 log stimulus energy (log cd.s/m²)) and in photopic conditions (1.3; 1.69; 2.0; 2.10; 2.30 log stimulus energy (log cd.s/m²)). Although minimal decays in amplitudes of a- and b- waves were detected after saline injection, there was no significant difference between baseline and after injection for the stimulus-response time of a- and b- waves (p>0.05). An unemployed EEG device can be effectively used for photic stimulation in experimental ERG in the studies of retinal toxicity.

[1]  A. Sacaan,et al.  Application of electroretinography (ERG) in early drug development for assessing retinal toxicity in rats. , 2015, Toxicology and applied pharmacology.

[2]  I. Perlman Testing retinal toxicity of drugs in animal models using electrophysiological and morphological techniques , 2009, Documenta Ophthalmologica.

[3]  B. Kolomiets,et al.  Retinal electrophysiology for toxicology studies: applications and limits of ERG in animals and ex vivo recordings. , 2008, Experimental and toxicologic pathology : official journal of the Gesellschaft fur Toxikologische Pathologie.

[4]  D. Hood,et al.  Assessing abnormal rod photoreceptor activity with the a-wave of the electroretinogram: Applications and methods , 1996, Documenta Ophthalmologica.

[5]  M. Brigell,et al.  Recommendations for a Toxicological Screening ERG Procedure in Laboratory Animals , 2005, Documenta Ophthalmologica.

[6]  R. Melendez,et al.  Retinal Function Assessed by ERG Before and After Induction of Ocular Aspergillosis and Treatment by the Anti-fungal, Micafungin, in Rabbits , 2005, Documenta Ophthalmologica.

[7]  L. Frishman,et al.  Photopic ERGs in patients with optic neuropathies: comparison with primate ERGs after pharmacologic blockade of inner retina. , 2004, Investigative ophthalmology & visual science.

[8]  S. Joly,et al.  Comparing the photopic ERG i-wave in different species. , 2004, Veterinary ophthalmology.

[9]  Y. Tazawa,et al.  Selective loss of the photopic negative response in patients with optic nerve atrophy. , 2004, Archives of ophthalmology.

[10]  L. Wachtmeister,et al.  Basic research and clinical aspects of the oscillatory potentials of the electroretinogram , 1987, Documenta Ophthalmologica.

[11]  J. Robson,et al.  The photopic negative response of the flash electroretinogram in primary open angle glaucoma. , 2001, Investigative ophthalmology & visual science.

[12]  G. Harding,et al.  Clinical Significance of EEG Abnormalities During Photic Stimulation in Patients with Photosensitive Epilepsy , 1999, Epilepsia.

[13]  M. McKerral,et al.  The i-wave: bridging flash and pattern electroretinography. , 1996, Electroencephalography and clinical neurophysiology. Supplement.

[14]  D. Norren,et al.  Origin of the oscillatory potentials in the primate retina , 1985, Vision Research.

[15]  G. Trick,et al.  Improved electrode for electroretinography. , 1979, Investigative ophthalmology & visual science.